<?xml version="1.0" encoding="UTF-8" standalone="no"?><metadata>
	<idinfo>
		<citation>
			<citeinfo>
				<origin>G. R. Robinson, Jr.</origin>
				<origin>K. E. Kapo</origin>
				<pubdate>2003</pubdate>
				<title Sync="TRUE">GISDATA.BEDROCKLITHOLOGY_POLY</title>
				<geoform Sync="TRUE">vector digital data</geoform>
				<serinfo>
					<sername>U.S. Geological Survey Open-File Report</sername>
					<issue>03-225</issue>
				</serinfo>
				<pubinfo>
					<pubplace>Reston, VA</pubplace>
					<publish>U.S. Geological Survey</publish>
				</pubinfo>
				<onlink Sync="FALSE">withheld</onlink>
				<ftname Sync="TRUE">GISDATA.BEDROCKLITHOLOGY_POLY</ftname>
</citeinfo>
		</citation>
		<descript>
			<abstract>
This geographic information system (GIS) data layer shows the
dominant lithology and geochemical, termed lithogeochemical,
character of near-surface bedrock in the New England region
covering the states of Connecticut, Maine, Massachusetts, New
Hampshire, Rhode Island, and Vermont. The bedrock units in the
map are generalized into groups based on their lithological
composition and, for granites, geochemistry.  Geologic provinces
are defined as time-stratigraphic groups that share common features
of age of formation, geologic setting, tectonic history, and lithology.

This data set incorporates data from digital maps of two NAWQA
study areas, the New England Coastal Basin (NECB) and the
Connecticut, Housatonic, and Thames River Basins (CONN) areas and
extends data to cover the states of Connecticut, Maine,
Massachusetts, New Hampshire, Rhode Island, and Vermont.
The result is a regional dataset for the lithogeochemical
characterization of New England (the layer named NE_LITH).
Polygons in the final coverage are attributed according
to state, drainage area, geologic province, general rock type,
lithogeochemical characteristics, and specific bedrock map unit.
</abstract>
			<purpose>
This geologic characterization provides a framework to interpret
regional geochemistry and habitat characteristics in relation to
bedrock lithology and geologic provinces that share common
features.  The lithogeochemical data layer combines and extends
data previously compiled for the U.S. Geological Survey National
Water Quality Assessment Program (NAWQA) study areas of the New
England Coastal Basin (NECB), and the Connecticut, Housatonic,
and Thames River Basins (CONN).  The coverage provides digital
geologic information that may be applied to the analysis of
water-quality characteristics of surface water and shallow ground
water, and soil and stream sediment characteristics based on
bedrock lithogeochemistry.

The geologic characterization provided in this classification is
intended to portray significant bedrock geologic features that
influence stream sediment and soil chemistry and water quality.

"Near-surface bedrock" in this report refers to lithified
materials covered by no more than about 60 feet of overlying
unconsolidated surficial materials.  The thickness of Quaternary
sediments overlying bedrock is generally less than 60 feet in
the New England states (Soller, 1993).

The bedrock units shown on the source maps were grouped and
generalized for this compilation.  Consequently this map
will show fewer geologic units and less detail than the
state geologic maps from which the information was drawn.

A few areas have been modified from those shown on the state
maps, for example, additional units portrayed by Smoot (1991) are
shown in the Hartford Basin area of Connecticut and Massachusetts
and mismatched contacts have been adjusted along state borders.

Based on the geologic map compilation scales, mismatches of some
unit contacts across state boundaries, and the positioneal
uncertainty of the source digital files relative to the published
geologic maps, the spatial accuracy of this compilation is
estimated as 1.5 km.

To the degree that surficial materials are related to their
proximal bedrock source, the variations in bedrock geology also
provide guidelines to the expected variation in the properties
and chemistry of surficial materials and surface waters. In
glaciated areas, such as New England, the mineralogy of tills and
some stratified drift is related to adjacent bedrock units, and
bedrock geology has been used to help define their chemical
character (Bailey and Hornbeck, 1992).  A lithogeochemical
framework similar to that provided in this report has been used
to define correlations between groundwater chemistry and bedrock
geology (Grady and Mullaney, 1988; Ayotte and others, 1999).
Groundwater chemistry for alkalinity, pH, Ca, Mg, Na, silica, and
radon in surficial aquifers sampled from wells up to 60 feet in
depth in surficial aquifers have been shown to correlate with
groups of lithology of the underlying bedrock (Grady and
Mullaney, 1988). Groundwater chemistry for pH, iron, manganese,
and arsenic in fractured crystalline bedrock aquifers sampled
from wells up to 500 feet in depth differ by bedrock lithology
groups (Ayotte and others, 1999; Ayotte and others, 2003).

The lithogeochemical characterization in these data have been
put to use analyzing water-quality characteristics in studies
by Grady and Mullaney (1998) and Ayotte and others (2003).
</purpose>
			<supplinf>
The lithogeochemical classification scheme for the New England
Lithology data set was first developed as part of the USGS's
study of the CONN area (Robinson and others, 1999). The
classification scheme is based on geochemical principles,
previous studies of the relations among water-quality and
ecosystem characteristics and rock type, and regional geology
(Robinson, 1997 and references cited within).  The classification
scheme and data set are intended to provide a general, flexible
framework to portray the lithologic character of mapped bedrock
units in New England in relation to regional geochemical and
water-quality data.

The data set is a lithologic map that has been coded to reflect
the potential influence of bedrock geology on water quality and
sediment chemistry. Information on the map unit identities
portrayed on the source bedrock geologic maps for each state
are retained in this digital dataset.

The bedrock units in New England have been mapped by time-
stratigraphic and other geologic criteria that may not be
directly relevant to variation in regional geochemistry and water
quality. Bedrock units depicted on the state geologic maps are
inconsistent across state boundaries in some areas.  Thus, a
regional coding scheme was developed to reclassify the geologic
map units according to mineralogical and chemical characteristics
that are relevant for analysis of regional variation in geochemistry
and water-quality.

To provide a framework for geochemical investigations, the
bedrock units were classified according to the chemical
composition (based upon the geologic maps used in the creation of
this data set) and the relative susceptibility to
weathering of their constituent minerals.  Although weathering
rates may vary, the relative stability of different minerals
during weathering in moist climates is generally consistent
(Robinson, 1997).  However, the degree to which a rock weathers
reflects the proportions of its constituent mineral as well as
many other factors such as degree of induration and relative
amount of mineral surfaces exposed to water through primary and
secondary porosity (Robinson, 1997 and references cited within).
Thus, although largely based on the relative stability of rock
constituent minerals, the classification scheme to group bedrock
units according to effects on soil and sediment chemistry and
water quality is more complex than mineral-stability sequences.
Most common rock-forming minerals are only sparingly soluble, so
small amounts of highly reactive minerals can have large
effects on water quality (Robinson, 1997; Grady and Mullaney,
1998).  For example, rocks containing significant amounts of
carbonate minerals are more rapidly weathered and tend to produce
higher solute concentrations in natural waters than many other
rock types.  In contrast, rock types such as granite, schist and
quartzite are rich in quartz, muscovite, and alkali-feldspars;
these minerals tend to produce low solute concentrations because
they react to a lesser degree and at slower rates than other mineral
types in humid temperate climates (Robinson, 1997).  Further
description of the lithogeochemical classification scheme and
the expected water-quality and ecosystem characteristics associated
with each lithogeochemical unit is explained in Robinson (1997).

The lithogeochemical classification scheme used in this data set
incorporates mineralogical information derived from published
descriptions of the bedrock geology map units with other
information on geologic features, such as metamorphic grade and
geologic setting. The attributes of lithology code ("Litho_code")
and modifier code ("Lith_mod") are used to express this
lithogeochemical coding of bedrock units.  Thirty-seven
lithogeochemical units (combinations of lithology and modifier
codes) are defined for the New England study region based on the
mineral and textural properties of the bedrock unit's constituent
minerals, presence of carbonate and sulfide minerals,
depositional setting (such as restricted deposition within fault
bounded sedimentary basins of Mississipian or younger age), and
for some of the granitic units, mineralogy and magma chemistry.
The classification scheme used descriptions from state and
regional geologic maps (Doll and others, 1961; Osberg and others,
1985; Lyons and others, 1997; Zen and others, 1983; Hermes and
others, 1994; and Rogers, 1985; Smoot, 1991). For Rhode Island
and Maine, source materials of the state geologic maps were
available as digital data layers (Osberg and others, 1985, Maine;
Hermes and others, 1994, 1:100,000 scale, Rhode Island).

Information from these sources included descriptions of the
lithology, mineralogy, and weathering characteristics of the
bedrock units.  For example, "rusty-weathering" serves as an
indicator of sulfidic-bearing bedrock units (Robinson, 1997).
Carbonate and sulfide minerals predominate in the classification
scheme because these highly reactive minerals have a
disproportionately large effect on water chemistry compared to
other minerals commonly found in the rocks of this region
(Robinson, 1997). In the Maine data set, information about
metamorphic grade was also used to classify bedrock units.  A
digital data layer of generalized regional metamorphic zones
(Guidotti, 1985, shown in Osberg and others, 1985, was obtained
from the Maine Geological Survey.  This layer was intersected
with the digital bedrock geology to determine the regional
metamorphic grade of each polygon in the bedrock geology data
layer.  Polygons lying within two metamorphic zones were split at
the metamorphic-zone boundary. Metamorphic grade and geochemical
composition of the protolith (pre-metamorphism source rock) were
used to classify polygons into lithogeochemical units.  For
example, bedrock units with protoliths of "limestone and (or)
dolostone" were classified as "limestone, dolomite, and
carbonate-rich clastic sediments" (lithogeochemical unit "11u")
in areas of little or no regional metamorphism and as "marble,
may include some calc-silicate rock" (lithogeochemical unit
"12u") in areas of greenschist facies or high-grade metamorphism.

Bibliographic References:

Ayotte, J.P., Nielsen, M.G., Robinson, G.R., Jr., Moore, R,B., 1999, Relation of arsenic, iron, and manganese in ground water to aquifer type, bedrock lithogeochemistry, and land use in the New England Coastal Basins, U. S. Geological Survey Water-Resources Investigative Report 99-4162, 61 p.

Ayotte, J.D., Montgomery, D.L., Flanagan, S.M., and Robinson, K.W., 2003, Arsenic in ground water in eastern New England: Occurrence, controls, and human health implications: Environmental Science and Technology, v. 37, no.10, p.2075-2083.

Bailey, S.W. and Hornbeck, J.W., 1992, Lithologic composition and rock weathering potential of forested, glacial-till soils, Research paper NE-662, Radnor PA: United States Department of Agriculture, Forest Service, Northeastern Forest Experimental Station, 7 p.

Doll, C.G., Cady, W.M., and Thompson, J.B., Jr., and Billings, M.P., eds. and compilers, 1961, Centennial Geology Map of Vermont: Montpelier, VT, U.S. Geological Survey, 1:250,000, 1 sheet. (transverse mercator projection, based on best available information).

Grady, S.J. and Mullaney, J.R., 1998, Natural and human factors affecting shallow water quality in surficial aquifers in the Connecticut, Housatonic, and Thames River Basins: U.S. Geological Survey Water-Resources Investigations Report 98-4042, 81 p.

Guidotti, C.V., 1985, Generalized map of regional metamorphic zones:in Osberg, P.H., and others: Augusta, Maine, Maine Geological Survey, 1 map sheet, 1:1,600,000.

Hermes, O.D., Gromet, L.P., Murray, D.P., 1994, Bedrock geologic map of Rhode Island: Kingston, R.I., Office of the Rhode Island State Geologist, Rhode Island Map Series No 1, 1 map sheet, 1:100,000.

Lyons, J.B., Bothner, W.A., Moench, R.H., and Thompson, J.B., Jr., 1997, Bedrock geologic map of New Hampshire:  Reston, Va., U.S. Geological Survey Special Map, 2 map sheets, 1:250,000.

McHone, J.G., and Butler, J.R. 1984. Mesozoic igneous provinces of New England and the opening of the North Atlantic Ocean: Geological Society of America Bulletin v.95, p. 757-765.

Osberg, P.H., Hussey, A.M. II, and Boone, G.M., 1985, Bedrock geologic map of Maine:  Augusta, Maine, Maine Geological Survey, 1 map sheet, 1:500,000.

Robinson, G.R., Jr., 1997, Portraying chemical properties of bedrock for water quality and ecosystem analysis: an approach for the New England Region: U.S. Geological Survey Open-File Report 97-154, 17 p.

Robinson, G.R., Jr., Peper, J.D., Steeves, P.A., and DeSimone, L.A., 1999, Lithogeochemical character of near-surface bedrock in the Connecticut, Housatonic, and Thames River Basins: U.S. Geological Survey, Water-Resources Investigations Report 99-4000 digital.

Robinson, G.R., Jr., Ayotte, J.P., Montgomery, D.C., and DeSimone, L.A. 2002, Lithogeochemical Character of Near-Surface Bedrock in the New England Coastal Basins: U.S. Geological Survey Open-File Report, 02-00 digital.

Rogers, John (compiler), 1985, Bedrock geological map of Connecticut: Connecticut Geologic and Natural History Survey, Natural Resource Atlas Map Series, 2 map sheets, 1:125,000.

Soller, D.R., 1993, Map showing the thickness and character of Quaternary sediments in the glaciated United States east of the Rocky Mountains - Northeastern states, the Great Lakes, and parts of southern Ontario and the Atlantic offshore area (east of 80o 31' west longitude): U.S. Geological Survey Miscellaneous Invistigations Series Map I-1970-A.

Smoot, J.P., 1991, Sedimentary facies and depositional environments of early Mesozoic Newark Supergroup basins, eastern North America: Paleogeography, Paleoclimatology, Paleoecology, v. 84, p. 369-423.

Zen, E-an, Goldsmith, G.R., Ratcliffe, N.L., Robinson, P., and Stanley, R.S., 1983, Bedrock geologic map of Massachusetts: U.S. Geological Survey, Monograph Series, 3 map sheets, 1:250,000.
</supplinf>
			<langdata Sync="TRUE">en</langdata>
</descript>
		<timeperd>
			<timeinfo>
				<sngdate>
					<caldate>2003</caldate>
				</sngdate>
			</timeinfo>
			<current>publication date</current>
		</timeperd>
		<status>
			<progress>Complete</progress>
			<update>None Planned</update>
		</status>
		<spdom>
			<bounding>
				<westbc Sync="TRUE">-73.524114</westbc>
				<eastbc Sync="TRUE">-69.898558</eastbc>
				<northbc Sync="TRUE">42.888349</northbc>
				<southbc Sync="TRUE">41.231479</southbc>
			</bounding>
			<lboundng>
<leftbc Sync="TRUE">34616.204799</leftbc>
<rightbc Sync="TRUE">330839.494799</rightbc>
<bottombc Sync="TRUE">777623.230214</bottombc>
<topbc Sync="TRUE">959747.440214</topbc>
</lboundng>
</spdom>
		<keywords>
			<theme>
				<themekt>None</themekt>
				<themekey>Lithogeochemical</themekey>
				<themekey>Bedrock</themekey>
				<themekey>Geology</themekey>
				<themekey>Geochemistry</themekey>
				<themekey>Stream sediment chemistry</themekey>
				<themekey>Lithology</themekey>
				<themekey>Mineral</themekey>
				<themekey>Water chemistry</themekey>
			</theme>
			<place>
				<placekt>None</placekt>
				<placekey>NECB NAWQA study unit</placekey>
				<placekey>CONN NAWQA study unit</placekey>
				<placekey>New England</placekey>
				<placekey>Maine</placekey>
				<placekey>Rhode Island</placekey>
				<placekey>Connecticut</placekey>
				<placekey>Massachusetts</placekey>
				<placekey>New Hampshire</placekey>
				<placekey>Vermont</placekey>
			</place>
		</keywords>
		<accconst>none</accconst>
		<useconst>none</useconst>
		<ptcontac>
			<cntinfo>
				<cntperp>
					<cntper>Gilpin R Robinson</cntper>
					<cntorg>U.S. Geological Survey, ER</cntorg>
				</cntperp>
				<cntaddr>
					<addrtype>mailing address</addrtype>
					<address>
Mail Stop 954
12201 Sunrise Valley Drive
</address>
					<city>Reston</city>
					<state>VA</state>
					<postal>20192</postal>
					<country>USA</country>
				</cntaddr>
				<cntvoice>703-648-6113</cntvoice>
				<cntfax>703-648-6383</cntfax>
				<cntemail>grobinso@usgs.gov</cntemail>
			</cntinfo>
		</ptcontac>
		<browse>
			<browsen>http://pubs.usgs.gov/of/2003/of03-225/Fig_1.jpg</browsen>
			<browsed>The drainage basins covered by this dataset, 745x548 pixels, 34k bytes.</browsed>
			<browset>JPEG</browset>
		</browse>
		<browse>
			<browsen>http://pubs.usgs.gov/of/2003/of03-225/Fig_2.jpg</browsen>
			<browsed>The geologic provinces of New England, 745x567 pixels, 47k bytes.</browsed>
			<browset>JPEG</browset>
		</browse>
		<browse>
			<browsen>http://pubs.usgs.gov/of/2003/of03-225/Fig_3.jpg</browsen>
			<browsed>General lithology distribution in New England (symbolized with attribute Rock_GpA), 745x551 pixels, 66k bytes.</browsed>
			<browset>JPEG</browset>
		</browse>
		<browse>
			<browsen>http://pubs.usgs.gov/of/2003/of03-225/Fig_4.jpg</browsen>
			<browsed>More specific lithology distribution in New England (symbolized with attribute Rock_GpB), 745x601 pixels, 71k bytes.</browsed>
			<browset>JPEG</browset>
		</browse>
		<datacred>
Individuals involved in the creation of the final New England Lithology (NE_LITH), CONN, and NECB coverages are listed as follows:

New England Lithology (final Coverage NE_LITH):

Gilpin R. Robinson, Jr.: U.S. Geological Survey, Reston, Va.
Primary  developer of the classification scheme. Preparation of source materials and information for combining the coverages into a general representation of New England Lithology.

Katherine E. Kapo: U.S. Geological Survey, Reston, Virginia. Assisted  in editing the coverage linework and attributes, creation of the final "New England Lithology" version, and compilation of the final metadata.

Joseph D. Ayotte: U.S. Geological Survey, Pembroke, New Hampshire. New England Coastal Basin NAWQA ground-water specialist; reviewed the construction of the combined coverage.

Laura Hayes: U.S. Geological Survey, Pembroke, New Hampshire. Reviewed the finalized coverage and metadata and provided corrections for the metadata and attribute table.

CONN Coverage:

Gilpin R. Robinson, Jr: Preparation of source materials and compilation of lithogeochemical units for Connecticut and Massachusetts regions; primary development of lithogeochemical classification scheme.

John D. Peper: Preparation of source materials and compilation
of lithogeochemical units for Vermont and New Hampshire regions;
additional development of lithogeochemical classification scheme.

Peter A. Steeves: Construction, revision, quality-assurance, and
documentation of the digital data layer and publication of the data layer as a digital map product.

Leslie A. DeSimone: Quality assurance, revision, and documentation
of the data layer and publication of the data layer as a digital
map product.

Stephen P. Garabedian: Connecticut River NAWQA chief; coordinating  personnel and funding, planning, oversight, and  review of the data layer

Stephen J. Grady: Connecticut River NAWQA ground-water specialist;
primary user of the resulting data; planning and definition of
water quality issues of the NAWQA study unit for use in development of the data layer and oversight of the initial data-layer construction phases.

Robert Sava, Jr: Digitizing and coding contributions in NH, MA, and VT

Shanon Wappel: Digitizing and coding contributions in CT

NECB Coverage:

Gilpin R. Robinson, Jr.: U.S. Geological Survey, Reston, VA.
Primary  developer of the classification scheme. Preparation of source materials and compilation of lithogeochemical units for Maine, Massachusetts, and Rhode Island.

John D. Peper: U.S. Geological Survey, Reston, VA. Preparation of source materials and compilation of lithogeochemical units for New Hampshire; secondary developer of the lithogeochemical classification scheme.

John C. Rader: U.S. Geological Survey, Marlboro, Massachusetts. Construction, revision, quality-assurance, and documentation of the original digital data layer.

Keith W. Robinson: U.S. Geological Survey, Pembroke, New Hampshire. New England Coastal Basin NAWQA Chief; Coordination of personnel and funding, planning, oversight, and review of the data layer.

Joseph D. Ayotte: U.S. Geological Survey, Pembroke, New Hampshire. New England Coastal Basin NAWQA ground-water specialist; primary user of the resulting data; planning and definition of the water-quality issues of the NAWQA study unit for use in development of the data layer and oversight of the data layer construction phases.

Leslie A. DeSimone: U.S. Geological Survey, Marlboro, Massachusetts.   Technical reviewer of original digital data layer.

Walt Bawiec: U.S. Geological Survey, Reston, Virginia. Colleague reviewer who performed technical reviews of the completed digital data set and metadata document.

Curtis Price: U.S. Geological Survey, Rapid City, South Dakota. Colleague reviewer who performed technical reviews of the completed digital data set and metadata document.

Sarah M. Flanagan: U.S. Geological Survey, Pembroke, New Hampshire. Edited the coverage and assisted in compilation and editing the metadata.

Laura Hayes: U.S. Geological Survey, Pembroke, New Hampshire. Created plots of the CONN lithogeochemical coverage and the NECB lithogeochemical coverage so that consistency along the study-unit border could be checked. Corrected the shift in the Massachusetts portion of the coverage. Assisted in compilation and editing of the NECB metadata.
</datacred>
		<native Sync="FALSE">ESRI ArcCatalog 8.3.0.800</native>
		<natvform Sync="FALSE">Feature Class</natvform>
</idinfo>
	<dataqual>
		<attracc>
			<attraccr>
Potential errors associated with the polygon labels and line
junctions were checked using the LABELERRORS and NODEERRORS
command in ARC/INFO. The ARC/INFO FREQUENCY command was used to
compare the assignments of the lithology code and modifier code
attributes to the state bedrock codes. After the CONN and NECB
data sets were combined, the lithological patterns and bedrock
designations were checked using reference state geologic maps
mentioned in the reference section, and corrections were made as
needed to the digital data sets for the final combined data set.

The scientific content of this digital data set underwent
technical review by two USGS scientists who have  knowledge of
the regional geology, and GIS and spatial-data production. The
data set was evaluated on positional accuracy, contextual
accuracy, attribute accuracy, and topological consistency.
</attraccr>
		</attracc>
		<logic>
Every polygon has a single label point and all polygons are closed.
The same lithologic unit may extend across a state line but have
different formation names in different states.

Discrepancies at state borders.  Compilation of the lithogeochemical
data layer using state geologic maps also resulted in some
discontinuities at state borders. The lithogeochemical unit
assigned to a bedrock unit was based primarily on its description
on the appropriate state geologic map. Because the information
contained on the individual state maps was interpreted and
assembled by different groups of geologists, the compiled data set
is not always internally consistent. In addition, the state map
descriptions have generalized the chemical and mineral-assemblage
characteristics of the bedrock units and formations across the
different states; thus, regional trends in lithology or metamorphic
grade may have resulted in different generalized descriptions of
the same geologic unit in adjacent states. Discrepancies across
state borders in the lithogeochemical data layer reflect these and
other inconsistencies among the state geologic maps that could not
be resolved with the existing information. However, the
lithogeochemical coding of geologic units is consistent in each
state.

Discrepancies at the Study Unit boundary:  The classification
scheme was first developed as part of the U.S. Geological Survey's
NAWQA study of the Connecticut, Housatonic, and Thames River
Basins (Robinson and others, 1999).  When the CONN and NECB
lithogeochemical data sets are plotted together, there are
discrepancies along the study unit boundaries between bedrock
lines, lithogeochemical units and major groups.  These
discrepancies are attributed to modifications in the
lithogeochemical classfication scheme since the publication of
Robinson and others (1999), specifically the granitic bedrock
units, which were subdivided into additional lithogeochemical units
with modifying attributes to indicate relative age.  In addition,
there are differences in digital source materials for the bedrock
data layers in New Hampshire and Massachusetts and difference in
the presence/occurrence of bedrock units between the different
study areas.  These discrepancies are more frequent when the data
set is viewed with the lithogeochemical units showing, and less
frequent when the data set is viewed with the major groups showing.
Overall, the bedrock units within the two study units were
classified in a consistent manner to create a regional product that
can be used to evaluate bedrock geology affect on water-quality
characteristics.

Where surficial deposits are derived from the local bedrock, the
data layer might also be used to describe the lithogeochemical
character of these materials. However, chemical characteristics of
natural waters associated with surficial deposits may differ from
that suggested by the lithogeochemical character of the bedrock
units to the extent that the surficial deposits consist of, or are
mixed with, materials transported from source areas with differing
lithogeochemical characteristics.
</logic>
		<complete>
This data set contains bedrock unit boundaries, lithogeochemical
boundaries, and rock group boundaries for the New England study
area, which combines the CONN and NECB study units. The CONN NAWQA
study unit includes most of Connecticut, western Massachusetts,
eastern Vermont, western New Hampshire and small parts of Rhode
Island, New York, and Quebec, Canada. The NECB NAWQA study area
encompasses 23,000 square miles in western and central Maine,
eastern Massachusetts, most of Rhode Island, and a small part of
eastern Connecticut. Included in the NECB study area are the
Kennebec, Androscogginn, Saco, Merrimack, Charles, and Blackstone
River Basins as well as all of Cape Cod.
</complete>
		<posacc>
			<horizpa>
				<horizpar>
The spatial accuracy of the geologic source information varies.
The source geologic map scales range from 1:100,000 to 1:500,000.
In addition, analysis near state boundaries may be limited
by the geologic map interpretation differences across state
boundaries. This New England Lithology coverage is limited by
variances related to these differences in source materials used
and interpretation of geologic information between the CONN and
NECB lithochemical mapping.

The spatial component of this data layer was compiled from five
different digital sources and, therefore, incorporates any
limitations associated with those individual state geologic
data layers as well as their source paper maps. The digital
sources were provided with minimal documentation, so it is
unknown how or with what accuracy they were digitized. The
scales of the original state bedrock maps range from 1:100,000
to 1:500,000. Based on the geologic map compilation scales,
mismatches of some unit contacts across state boundaries, and
the positioneal uncertainty of the source digital files
relative to the published geologic maps, the spatial accuracy
of this New England Lithology compilation is estimated as 1.5 km.
</horizpar>
			</horizpa>
		</posacc>
		<lineage>
			<srcinfo>
				<srccite>
					<citeinfo>
						<origin>John B. Lyons</origin>
						<origin>Wallace A. Bothner</origin>
						<origin>Robert H. Moench</origin>
						<origin>James B. Thompson Jr.</origin>
						<pubdate>(unpublished)</pubdate>
						<title>Digital bedrock geologic map of New Hampshire</title>
						<geoform>map</geoform>
					</citeinfo>
				</srccite>
				<srcscale>250000</srcscale>
				<srctime>
					<timeinfo>
						<sngdate>
							<caldate>1997</caldate>
						</sngdate>
					</timeinfo>
					<srccurr>date data were provided</srccurr>
				</srctime>
				<srccitea>NHBedrock</srccitea>
				<srccontr>
Provided internal line work and initial polygon attribute data for New Hampshire.

Digitizing was performed at the Complex Systems Research Center, University of New Hampshire, from the Bedrock geologic map of New Hampshire (Lyons and others, 1997).
</srccontr>
			</srcinfo>
			<srcinfo>
				<srccite>
					<citeinfo>
						<origin>Osberg, P.H.</origin>
						<origin>Hussey, A.M. II</origin>
						<origin>Boone, G.M.</origin>
						<pubdate>1985</pubdate>
						<title>Bedrock geologic map of Maine</title>
						<geoform>map</geoform>
						<pubinfo>
							<pubplace>Augusta, Maine</pubplace>
							<publish>Maine Geological Survey</publish>
						</pubinfo>
					</citeinfo>
				</srccite>
				<srcscale>500000</srcscale>
				<srccitea>MEBedrock</srccitea>
				<srccontr>
Provided internal line work and initial polygon attribute data for Maine.

Digitized from the Bedrock Geologic Map of Maine (Osberg and others, 1985). This coverage contains statewide bedrock geology map units and major faults as mapped by the Maine Geologic Survey (MGS).
</srccontr>
			</srcinfo>
			<srcinfo>
				<srccite>
					<citeinfo>
						<origin>Osberg, P.H.</origin>
						<origin>Hussey, A.M. II</origin>
						<origin>Boone, G.M.</origin>
						<pubdate>1985</pubdate>
						<title>Bedrock geologic map of Maine: Generalized regional metamorphic zones</title>
						<geoform>map</geoform>
						<pubinfo>
							<pubplace>Augusta, Maine</pubplace>
							<publish>Maine Geological Survey</publish>
						</pubinfo>
					</citeinfo>
				</srccite>
				<srcscale>1600000</srcscale>
				<srccitea>Maine metamorphic data</srccitea>
				<srccontr>
Provided internal line work and initial polygon attribute data for metamorphic zones in Maine.

Digitized from the Bedrock Geologic Map of Maine (Osberg and others, 1985). This coverage contains generalized regional metamorphic zones as mapped by the Maine Geologic Survey (MGS).
</srccontr>
			</srcinfo>
			<srcinfo>
				<srccite>
					<citeinfo>
						<origin>Rogers, John (compiler)</origin>
						<pubdate>1985</pubdate>
						<title>Bedrock geological map of Connecticut</title>
						<geoform>map</geoform>
						<serinfo>
							<sername>Natural Resource Atlas Map Series</sername>
						</serinfo>
						<pubinfo>
							<publish>Connecticut Geologic and Natural History Survey</publish>
						</pubinfo>
					</citeinfo>
				</srccite>
				<srcscale>125000</srcscale>
				<typesrc>paper</typesrc>
				<srctime>
					<timeinfo>
						<sngdate>
							<caldate>1985</caldate>
						</sngdate>
					</timeinfo>
					<srccurr>publication date</srccurr>
				</srctime>
				<srccitea>CTBedrock</srccitea>
				<srccontr>Provided internal line work and initial polygon attribute data for Connecticut.</srccontr>
			</srcinfo>
			<srcinfo>
				<srccite>
					<citeinfo>
						<origin>Zen, E-an</origin>
						<origin>Goldsmith, G. Richard</origin>
						<origin>Ratcliffe, N.L.</origin>
						<origin>Robinson, Peter</origin>
						<origin>Stanley, R.S.</origin>
						<origin>Hatch, N.L.</origin>
						<origin>Shride, A.F.</origin>
						<origin>Weed, E.G.A.</origin>
						<origin>Wones, D.R.</origin>
						<pubdate>1983</pubdate>
						<title>Bedrock geologic map of Massachusetts</title>
						<pubinfo>
							<pubplace>Reston, VA</pubplace>
							<publish>U.S. Geological Survey</publish>
						</pubinfo>
					</citeinfo>
				</srccite>
				<srcscale>250000</srcscale>
				<typesrc>paper</typesrc>
				<srctime>
					<timeinfo>
						<sngdate>
							<caldate>1983</caldate>
						</sngdate>
					</timeinfo>
					<srccurr>publication date</srccurr>
				</srctime>
				<srccitea>MABedrock</srccitea>
				<srccontr>
Provided internal line work and initial polygon attribute data.

Rudolph Hon digitized from the Bedrock geologic map of Massachusetts (Zen and others, 1983) under the direction of Rudolph Hon (Department of Geology, Boston College) as part of a project funded by the Massachusetts Highway Department.

Rudolph Hon provided reference to correct registration problems in the bedrock polygon lines in MABedrock.
</srccontr>
			</srcinfo>
			<srcinfo>
				<srccite>
					<citeinfo>
						<origin>Hermes, O.D.</origin>
						<origin>Gromet, L.P.</origin>
						<origin>Murray, D.P</origin>
						<origin>N.A. Hamidzada</origin>
						<origin>J.W. Skehan</origin>
						<origin>S. Mosher</origin>
						<pubdate>1994</pubdate>
						<title>Bedrock geologic map of Rhode Island</title>
						<geoform>map</geoform>
						<serinfo>
							<sername>Rhode Island map series</sername>
							<issue>1</issue>
						</serinfo>
						<pubinfo>
							<pubplace>Kingston, Rhode Island</pubplace>
							<publish>University of Rhode Island</publish>
						</pubinfo>
					</citeinfo>
				</srccite>
				<srcscale>100000</srcscale>
				<typesrc>paper</typesrc>
				<srctime>
					<timeinfo>
						<sngdate>
							<caldate>1994</caldate>
						</sngdate>
					</timeinfo>
					<srccurr>publication date</srccurr>
				</srctime>
				<srccitea>RIBedrock</srccitea>
				<srccontr>Provided internal linework and initial polygon attribute data for Rhode Island.</srccontr>
			</srcinfo>
			<srcinfo>
				<srccite>
					<citeinfo>
						<origin>Doll, G.C. (editor and compiler)</origin>
						<origin>Cady, W.M. (editor and compiler)</origin>
						<origin>Thompson, J.B. Jr. (editor and compiler)</origin>
						<origin>Billings, M.P. (editor and compiler)</origin>
						<title>Centennial geologic map of Vermont</title>
						<geoform>map</geoform>
						<pubinfo>
							<pubplace>Montpelier, VT</pubplace>
						</pubinfo>
					</citeinfo>
				</srccite>
				<srcscale>250000</srcscale>
				<typesrc>paper</typesrc>
				<srccitea>VTBedrock</srccitea>
				<srccontr>Information about Vermont</srccontr>
			</srcinfo>
			<procstep>
				<procdesc>
Digital versions of the state geologic maps were obtained from
the originators or authors for Maine (Marc Loiselle, Maine
Geological Survey, Augusta, ME), New Hampshire (U.S. Geological
Survey), Rhode Island (N. Hamidzeda, University of Rhode
Island, Department of Geology, Kingston, RI), and
Massachusetts, (Rudolph Hon, Department of Geology, Boston
College). The bedrock polylines of Connecticut were pieced
together from two digital sources; the Bedrock Geologic map of
Rhode Island (which shows a buffer of the adjacent state
bedrock units) and the Bedrock Geologic map of Connecticut.
Hence some of the bedrock line work and geologic names in
Connecticut are from the Bedrock Geologic map of Rhode Island.
</procdesc>
				<procdate>1997</procdate>
			</procstep>
			<procstep>
				<procdesc>
The original digital state bedrock data layers were combined
into one study-unit wide data layer using the ARC/INFO MAPJOIN
command. The individual coverages did not match perfectly at
the state borders, so the resulting sliver polygons had to be
deleted.
</procdesc>
				<procdate>1997-2001</procdate>
			</procstep>
			<procstep>
				<procdesc>
A lithogeochemical unit, lithology code, modifier code, major
group code, and state abbreviation were added as attributes to
each bedrock polygon present in the digital state geologic
maps. The statewide data layers were then clipped and mapjoined
to create a data layer for the NECB study unit.  State
boundaries were maintained in the combined data layer.
</procdesc>
				<procdate>1997-2001</procdate>
			</procstep>
			<procstep>
				<procdesc>
The original source data (MABedrock) for the Massachusetts
portion of this data layer contained some georeferencing
problems, which caused the arcs to display generally southwest
of their true locations, although the direction and distance of
the shift was not uniform across the state. Rudolph Hon
developed a method of re-registering the scanned image of the
paper map (Zen and others, 1983) based on thousands of control
points from USGS topographic maps, and digitized the bedrock
polygons again. This updated digital version of the
Massachusetts bedrock was obtained from the Eastern Mineral
Resources Team (USGS - Reston, Virginia) and showed improved
horizontal accuracy. Arcs from this updated bedrock coverage
were used as locational reference for the Massachusetts
linework in the NECB lithogeochemical coverage and the original
lithogeochemical label points with attributes were retained and
shifted to match the newly located polygons. Arcs near the
state and study unit boundaries were edited exactly to meet the
borders, and other minor corrections to linework and labels
were made.
</procdesc>
				<procdate>2001</procdate>
			</procstep>
			<procstep>
				<procdesc>
NECB metadata created using FGDCMETA.AML ver. 1.35 08/02/2000
on ARC/INFO data set.
</procdesc>
				<procdate>2000-2001</procdate>
			</procstep>
			<procstep>
				<procdesc>
The CONN and NECB data sets were combined using mapjoin
functions in ARC/INFO. Attributes for the NECB coverage were
edited to create a uniform attribute table (the CONN attribute
format was edited to follow the NECB attribute format). The
NECB data set used in the join was an earlier version without
the corrected work done in Massachusetts, so the horizontal
accuracy of the coverage was in need of improvement again in a
section of Massachusetts.
</procdesc>
				<procdate>2000-2001</procdate>
			</procstep>
			<procstep>
				<procdesc>
The georeferencing issue of Massachusetts was addressed for the
combined CONN/NECB data set by replacing the shifted portion of
the Massachussetts linework with the re-registered linework
from the corrected NECB data set. Bedrock polygons of
Massachusetts starting at and to the east of the western border
of the Mesozoic Basin were deleted and replaced with the re-
registered polygons of the NECB data set, using ARC/INFO map
join and editing features. Original arcs that were shared
boundaries between Massachusetts and other states were saved in
the combined coverage.
</procdesc>
				<procdate>2002</procdate>
			</procstep>
			<procstep>
				<procdesc>
A small section of western Massachusetts and three small
missing portions of western Connecticut (along the northwest
border) that had been lost at some point in the combination of
the data sets were added from the original CONN data set using
ARC/INFO map join. Polygons located in Canada and New York were
removed from the data set to limit the New England coverage to
six states (Connecticut, Massachusetts, Maine, New Hampshire,
Rhode Island, and Vermont).
</procdesc>
				<procdate>2002</procdate>
			</procstep>
			<procstep>
				<procdesc>
Additional edits were made to the attributes of the New England
data set using the paper copies state geologic maps (those
mentioned above as references for all digital CONN and NECB
data sets) for lithological information. Additional
attributes (such as province groups) were added based on
research needs. All edits to attributes were reviewed by Gilpin
R. Robinson, Jr., an originator of the data set.
</procdesc>
				<procdate>2002-2003</procdate>
			</procstep>
			<procstep>
				<procdesc>
Metadata from the CONN and NECB data sets was combined and
revised in html and .pdf format.
</procdesc>
				<procdate>2002-2003</procdate>
			</procstep>
			<procstep>
				<procdesc>
State border polygon discrepancies that could be addressed were
edited by correcting cross-border line shifts with new
linework.
</procdesc>
				<procdate>2003</procdate>
			</procstep>
			<procstep>
				<procdesc>
The finalized coverage and metadata were reviewed by Laura
Hayes (U.S. Geological Survey, Pembroke, New Hampshire); small
edits to the metadata and attribute table were made.
</procdesc>
				<procdate>2003</procdate>
			</procstep>
			<procstep>
<procdesc Sync="TRUE">Metadata imported.</procdesc>
<srcused Sync="FALSE">withheld</srcused>
<date Sync="TRUE">20040113</date>
<time Sync="TRUE">13122700</time>
</procstep>
<procstep>
<procdesc Sync="TRUE">Dataset copied.</procdesc>
<srcused Sync="FALSE">withheld</srcused>
<date Sync="TRUE">20040113</date>
<time Sync="TRUE">13172100</time>
</procstep>
</lineage>
	</dataqual>
	<spdoinfo>
		<direct Sync="TRUE">Vector</direct>
		<ptvctinf>
<esriterm Name="GISDATA.BEDROCKLITHOLOGY_POLY">
<efeatyp Sync="TRUE">Simple</efeatyp>
<efeageom Sync="TRUE">Polygon</efeageom>
<esritopo Sync="TRUE">FALSE</esritopo>
<efeacnt Sync="TRUE">2886</efeacnt>
<spindex Sync="TRUE">TRUE</spindex>
<linrefer Sync="TRUE">FALSE</linrefer>
</esriterm>
<sdtsterm Name="GISDATA.BEDROCKLITHOLOGY_POLY">
<sdtstype Sync="TRUE">G-polygon</sdtstype>
<ptvctcnt Sync="TRUE">2886</ptvctcnt>
</sdtsterm>
</ptvctinf>
</spdoinfo>
	<spref>
		<horizsys>
			<geodetic>
				<horizdn Sync="TRUE">North American Datum of 1983</horizdn>
				<ellips Sync="TRUE">Geodetic Reference System 80</ellips>
				<semiaxis Sync="TRUE">6378137.000000</semiaxis>
				<denflat Sync="TRUE">298.257222</denflat>
			</geodetic>
			<cordsysn>
<geogcsn Sync="TRUE">GCS_North_American_1983</geogcsn>
<projcsn Sync="TRUE">NAD_1983_StatePlane_Massachusetts_Mainland_FIPS_2001</projcsn>
</cordsysn>
<planar>
<planci>
<plance Sync="TRUE">coordinate pair</plance>
<plandu Sync="TRUE">meters</plandu>
<coordrep>
<absres Sync="TRUE">0.010000</absres>
<ordres Sync="TRUE">0.010000</ordres>
</coordrep>
</planci>
<gridsys>
<gridsysn Sync="TRUE">State Plane Coordinate System 1983</gridsysn>
<spcs>
<spcszone Sync="TRUE">2001</spcszone>
<lambertc>
<stdparll Sync="TRUE">41.716667</stdparll>
<stdparll Sync="TRUE">42.683333</stdparll>
<longcm Sync="TRUE">-71.500000</longcm>
<latprjo Sync="TRUE">41.000000</latprjo>
<feast Sync="TRUE">200000.000000</feast>
<fnorth Sync="TRUE">750000.000000</fnorth>
</lambertc>
</spcs>
</gridsys>
</planar>
</horizsys>
		<vertdef>
<altsys>
<altenc Sync="TRUE">Explicit elevation coordinate included with horizontal coordinates</altenc>
<altres Sync="TRUE">1.000000</altres>
</altsys>
</vertdef>
</spref>
	<eainfo>
		<detailed Name="GISDATA.BEDROCKLITHOLOGY_POLY">
			<enttyp>
				<enttypl Sync="TRUE">GISDATA.BEDROCKLITHOLOGY_POLY</enttypl>
				<enttypd>
Polygonal map units define bedrock areas with similar lithologic
and geochemical properties.
</enttypd>
				<enttypt Sync="TRUE">Feature Class</enttypt>
<enttypc Sync="TRUE">2886</enttypc>
</enttyp>
			<attr>
				<attrlabl Sync="TRUE">OBJECTID</attrlabl>
				<attrdef Sync="TRUE">Internal feature number.</attrdef>
				<attrdomv>
					<edom>
						<edomv>CT</edomv>
						<edomvd>Connecticut</edomvd>
					</edom>
					<edom>
						<edomv>MA</edomv>
						<edomvd>Massachusetts</edomvd>
					</edom>
					<edom>
						<edomv>ME</edomv>
						<edomvd>Maine</edomvd>
					</edom>
					<edom>
						<edomv>NH</edomv>
						<edomvd>New Hampshire</edomvd>
					</edom>
					<edom>
						<edomv>RI</edomv>
						<edomvd>Rhode Island</edomvd>
					</edom>
					<edom>
						<edomv>VT</edomv>
						<edomvd>Vermont</edomvd>
					</edom>
					<udom Sync="TRUE">Sequential unique whole numbers that are automatically generated.</udom>
</attrdomv>
				<attalias Sync="TRUE">OBJECTID</attalias>
<attrtype Sync="TRUE">OID</attrtype>
<attwidth Sync="TRUE">4</attwidth>
<atprecis Sync="TRUE">10</atprecis>
<attscale Sync="TRUE">0</attscale>
<attrdefs Sync="TRUE">ESRI</attrdefs>
</attr>
			<attr>
				<attrlabl Sync="TRUE">STATE</attrlabl>
				<attrdef>
The coverage is divided by drainage basins based on the USGS
National Water Quality Assessment (NAWQA) study areas CONN and
NECB. NAWQA program information can be accessed at

http://water.usgs.gov/nawqa/studyu.html

For purposes of focusing on the area of New England in this
coverage, two new drainage areas have been added to the coverage:
Northern Maine (N_MAINE) and St. Lawrence/Hudson River (STL_HUD)
drainage areas. The N_MAINE drainage area covers the area in
Maine not included in the NECB study area. The STL_HUD drainage
area combines the small portion of the NAWQA Hudson River basin
included in this coverage, and the area of northern Vermont not
included in a NAWQA study area.
</attrdef>
				<attrdefs>National Water Quality Assessment Program</attrdefs>
				<attrdomv>
					<edom>
						<edomv>NECB</edomv>
						<edomvd>New England Coastal Basin</edomvd>
						<edomvds>U.S. Geological Survey</edomvds>
					</edom>
					<edom>
						<edomv>CONN</edomv>
						<edomvd>Connecticut, Housatonic, and Thames River Basins</edomvd>
						<edomvds>U.S. Geological Survey</edomvds>
					</edom>
					<edom>
						<edomv>STL_HUD</edomv>
						<edomvd>St. Lawrence-Hudson River Basins</edomvd>
						<edomvds>U.S. Geological Survey</edomvds>
					</edom>
					<edom>
						<edomv>N_MAINE</edomv>
						<edomvd>Northern Maine</edomvd>
						<edomvds>U.S. Geological Survey</edomvds>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">STATE</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">8</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">HYDRO_BSN</attrlabl>
				<attrdef>
The bedrock units shown on the individual state maps for the New
England study area have been grouped into 10 geologic provinces.
The map units in each province group share common features of
lithology, age of formation, geologic setting, and tectonic history.
The province groups generally occur as northeast-trending belts that
follow the structural fabric of the Appalachian foldbelt and faults
in New England.

The tectonic map features contained with the state-level
bedrock geologic maps and the grouping of bedrock map units
by geologic belts in the legends of the state-level bedrock
geologic maps were used to define province attributes.
</attrdef>
				<attrdomv>
					<edom>
						<edomv>Avalon Belt</edomv>
						<edomvd>
Avalon Belt terrane, Avalon Province

Localized in eastern Massachusetts, Rhode Island, and coastal Connecticut. Principally Precambrian Z granite and granitic gneiss and metasedimentary rocks of Precambrian Z to Ordovician age. Intruded by Ordovician to Devonian granites. Cretaceous sediments and thick areas of Quaternary glacial sediments occur in southern coastal areas.
</edomvd>
					</edom>
					<edom>
						<edomv>Bronson Hill Sequence</edomv>
						<edomvd>
Bronson Hill Sequence terrane

Triassic to Jurassic age sediments and basalt flows deposited in localized rift basins in from Connecticut to western New Hampshire and northern Maine. Principally Ordovician igneous and metavolcanic rocks overlain by Ordovician to Devonian metasedimentary rocks. Sulfidic schists and mafic rocks are common. Intruded by Devonian granites.
</edomvd>
					</edom>
					<edom>
						<edomv>Coastal Maine</edomv>
						<edomvd>
Coastal Maine terrane

Localized along northeastern coastal Maine. Principally PreCambrian Z to Silurian metasedimentary and metavolcanic rocks intruded by Devonian granites.
</edomvd>
					</edom>
					<edom>
						<edomv>Eugeosyncline Sequence</edomv>
						<edomvd>
Eugeosyncline Sequence terrane

Includes slates and pelitic metamorphic rocks in the Taconic Range and schists east of the Grenville Belt. Principally Cambrian to Ordovician pelitic metasedimentary rocks, including metavolcanic layers and lenses of ultramafic rocks.
</edomvd>
					</edom>
					<edom>
						<edomv>Grenville Belt</edomv>
						<edomvd>
Grenville Belt terrane

Includes areas of Grenville Basement (PreCambrian Y metamorphic rocks) in western Connecticut, Massachusetts, and Vermont. Principally granitic gneiss and metasedimentary rocks. Includes some Cambrian metasedimentary rocks deposited on Precambrian basement.
</edomvd>
					</edom>
					<edom>
						<edomv>Grenville Shelf Sequence</edomv>
						<edomvd>
Grenville Shelf Sequence terrane

Principally carbonate rocks and other metasedimentary rocks deposited in a carbonate  shelf sequence overlying Grenville basement in western Connecticut, Massachusetts, and Vermont.
</edomvd>
					</edom>
					<edom>
						<edomv>Mesozoic Basin</edomv>
						<edomvd>
Mesozoic Basin terrane

Triassic to Jurassic age sediments and basalt flows deposited in localized rift basins in central Connecticut and Massachusetts. Intruded by Jurassic diabase and basalt dikes.
</edomvd>
					</edom>
					<edom>
						<edomv>NH - Maine Sequence</edomv>
						<edomvd>
NH-ME terrane, New Hampshire-Maine Sequence

Covers eastern Connecticut, central Massachusetts, eastern New Hampshire, and central Maine. Principally Silurodevonian metasedimentary rocks and Silurodevonian and younger igneous rocks, principally granite.
</edomvd>
					</edom>
					<edom>
						<edomv>Narragansett Basin</edomv>
						<edomvd>
Narragansett basin terrane

Permian conglomerates and other sediments deposited in fault-bounded basins in Avalon province  rocks in southeastern Massachusetts and Rhode Island.
</edomvd>
					</edom>
					<edom>
						<edomv>Waits River-Gile Mt. S</edomv>
						<edomvd>
Waits River Gile Mt. Sequence terrane

Principally Devonian variably-calcareous metasedimentary rocks in eastern Vermont and the northern Connecticut valley in Massachusetts, intruded by Devonian granite.
</edomvd>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">HYDRO_BSN</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">25</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">G_PROVINCE</attrlabl>
				<attrdef>A one- or two-letter abbreviation for the geologic provinces.</attrdef>
				<attrdomv>
					<edom>
						<edomv>B</edomv>
						<edomvd>Bronson Hill Sequence</edomvd>
					</edom>
					<edom>
						<edomv>C</edomv>
						<edomvd>Waits River-Gile Mt. Sequence</edomvd>
					</edom>
					<edom>
						<edomv>CM</edomv>
						<edomvd>Coastal Maine</edomvd>
					</edom>
					<edom>
						<edomv>H</edomv>
						<edomvd>Eugeosyncline Sequence</edomvd>
					</edom>
					<edom>
						<edomv>M</edomv>
						<edomvd>NH - Maine Sequence</edomvd>
					</edom>
					<edom>
						<edomv>N</edomv>
						<edomvd>Mesozoic Basin</edomvd>
					</edom>
					<edom>
						<edomv>NB</edomv>
						<edomvd>Narragansett basin</edomvd>
					</edom>
					<edom>
						<edomv>S</edomv>
						<edomvd>Grenville Shelf Sequence</edomvd>
					</edom>
					<edom>
						<edomv>Y</edomv>
						<edomvd>Grenville Belt</edomvd>
					</edom>
					<edom>
						<edomv>Z</edomv>
						<edomvd>Avalon Province</edomvd>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">G_PROVINCE</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">25</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">G_PROV_ID</attrlabl>
				<attrdef>
A broad categorization of lithogeochemical units.  Each
category under these headings shares similarities in overall
geochemistry and lithology.
</attrdef>
				<attrdomv>
					<edom>
						<edomv>Basin Sedimentary</edomv>
						<edomvd>
Sediments deposited in fault-bounded basins of Permian
and younger age.
</edomvd>
					</edom>
					<edom>
						<edomv>Calcpelite</edomv>
						<edomvd>
Calcareous clastic and metaclastic rocks containing
approximately 15-45% carbonate minerals.
</edomvd>
					</edom>
					<edom>
						<edomv>Carbonate Rocks</edomv>
						<edomvd>
General rock composition carbonate rock, includes
limestone, dolomite, and marble with mixed calc-silicate
rocks.
</edomvd>
					</edom>
					<edom>
						<edomv>Granites</edomv>
						<edomvd>General rock composition granite.</edomvd>
					</edom>
					<edom>
						<edomv>Mafic Rocks</edomv>
						<edomvd>
General rock composition mafic igneous rocks and their
metamorphic equivalents.
</edomvd>
					</edom>
					<edom>
						<edomv>Metamorphic Rocks Undivi</edomv>
						<edomvd>
Metamorphic rocks other than carbonate rocks,
calcpelite, or mafic rocks.
</edomvd>
					</edom>
					<edom>
						<edomv>Unconsolidated Sediments</edomv>
						<edomvd>
Unconsolidated or poorly consolidated sediments of
tertiary and younger age.
</edomvd>
					</edom>
					<edom>
						<edomv>Water</edomv>
						<edomvd>Inland freshwater body</edomvd>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">G_PROV_ID</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">15</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">ROCK_GPA</attrlabl>
				<attrdef>
Further subdivides the broad categories of lithgeochemical
units defined by Rock_GpA.
</attrdef>
				<attrdomv>
					<edom>
						<edomv>Alkali Granite (White Mt)</edomv>
						<edomvd>
Alkali granites associated with the White Mountain
Plutonic-Volcanic suite (Lyons and others, 1997. Includes
granitic rocks in the New England-Quebec and White
Mountain igneous provinces of McHone and Butler (1984).
</edomvd>
					</edom>
					<edom>
						<edomv>Avalon Granite</edomv>
						<edomvd>Granite of Precambrian Z age in the Avalon province.</edomvd>
					</edom>
					<edom>
						<edomv>Basalts</edomv>
						<edomvd>Basalts.</edomvd>
					</edom>
					<edom>
						<edomv>Calcpelite</edomv>
						<edomvd>
Calcareous clastic and metaclastic rocks containing
Approximately 15-45% carbonate minerals.
</edomvd>
					</edom>
					<edom>
						<edomv>Calcgranofels</edomv>
						<edomvd>
Fine-grained calcareous clastic and metaclastic rocks
containing calc-silicate minerals. May contain a small
percentage of carbonate minerals.
</edomvd>
					</edom>
					<edom>
						<edomv>Carbonate rocks</edomv>
						<edomvd>
General rock composition carbonate rock, includes
limestone, dolomite, and marble with mixed calc-silicate
rocks.
</edomvd>
					</edom>
					<edom>
						<edomv>Felsic Volcanics</edomv>
						<edomvd>
Felsic volcanic rocks and mixed volcanic rocks where
felsic volcanics predominate.
</edomvd>
					</edom>
					<edom>
						<edomv>Granite, other</edomv>
						<edomvd>Granite, other than types listed below.</edomvd>
					</edom>
					<edom>
						<edomv>Grenville Granite</edomv>
						<edomvd>
Granite of the Precambrian Y age in Grenville basement
rocks.
</edomvd>
					</edom>
					<edom>
						<edomv>Mafic Rocks</edomv>
						<edomvd>Mafic igneous rocks and their metamorphic equivalents.</edomvd>
					</edom>
					<edom>
						<edomv>Mesozoic Basin Sediments</edomv>
						<edomvd>
Triassic-Jurassic continental sediments deposited in rift
basins of Mesozoic age.
</edomvd>
					</edom>
					<edom>
						<edomv>Metamorphic Rocks Undivi</edomv>
						<edomvd>
Metamorphic rocks other than carbonate rocks, calpelite,
calcgranofels, pelitic rocks, sulfidic schists, or mafic
rocks.
</edomvd>
					</edom>
					<edom>
						<edomv>Narragansett Basin Sediment</edomv>
						<edomvd>
Permian continental sediments deposited in fault-bounded
Permian basin.
</edomvd>
					</edom>
					<edom>
						<edomv>Pelitic Rocks</edomv>
						<edomvd>
Pelitic rocks and interbedded pelitic and sandy sediments
and their metamorphic equivalents.
</edomvd>
					</edom>
					<edom>
						<edomv>Peraluminous granite</edomv>
						<edomvd>
Granite types containing primary muscovite, of Late
Devonian to Carboniferous age.
</edomvd>
					</edom>
					<edom>
						<edomv>Sulfidic Schists</edomv>
						<edomvd>
Metamorphosed pelitic rocks containing sufficient pyrite
and(or) pyrrhotite to develop a rusty-weathering
characteristic.
</edomvd>
					</edom>
					<edom>
						<edomv>Ultramafic Rocks</edomv>
						<edomvd>Serpentine, dunite, and other ultramafic rocks.</edomvd>
					</edom>
					<edom>
						<edomv>Unconsolidated Sediments</edomv>
						<edomvd>
Unconsolidated and poorly consolidated sediments of
tertiary or younger age.
</edomvd>
					</edom>
					<edom>
						<edomv>Water</edomv>
						<edomvd>Inland bodies of fresh water.</edomvd>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">ROCK_GPA</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">24</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">ROCK_GPB</attrlabl>
				<attrdef>Numerical code for Rock_GpB values.</attrdef>
				<attrdomv>
					<edom>
						<edomv>0</edomv>
						<edomvd>Inland body of fresh water</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>1</edomv>
						<edomvd>Carbonate rocks</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>10</edomv>
						<edomvd>Calcpelite</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>11</edomv>
						<edomvd>Calcgranofels</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>20</edomv>
						<edomvd>Mesozoic basin sediments</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>21</edomv>
						<edomvd>Narragansett basin sediments</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>3</edomv>
						<edomvd>Metamorphic rocks, undivided</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>30</edomv>
						<edomvd>Pelitic rocks</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>31</edomv>
						<edomvd>Sulfidic schists</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>4</edomv>
						<edomvd>Mafic rocks</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>41</edomv>
						<edomvd>Basalts</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>5</edomv>
						<edomvd>Ultramafic rocks</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>6</edomv>
						<edomvd>Granite, other</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>60</edomv>
						<edomvd>Felsic volcanics</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>61</edomv>
						<edomvd>Grenville granites</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>62</edomv>
						<edomvd>Avalon granites</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>63</edomv>
						<edomvd>Peraluminous granites</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>64</edomv>
						<edomvd>Alkali granite (White Mt)</edomvd>
					</edom>
				</attrdomv>
				<attrdomv>
					<edom>
						<edomv>7</edomv>
						<edomvd>
Unconsolidated sediments

This includes both non-consolidated and poorly consolidated sediments, and encompasses areas in the south-coastal part of the New England study area where the bedrock is overlain by thick glacial sediments at the surface.  These surficial glacial deposits are the primary aquifer for these areas.
</edomvd>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">ROCK_GPB</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">24</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">R_GPB_ID</attrlabl>
				<attrdef>
Lithogeochemical classification code, developed for this data
set.  Field is defined as double (width 16, 3 digits to right
of the decimal) but all values are integer.
</attrdef>
				<attrdomv>
					<edom>
						<edomv>-9999</edomv>
						<edomvd>(surface water body)</edomvd>
					</edom>
					<edom>
						<edomv>11</edomv>
						<edomvd>limestone, dolomite, and carbonate-rich clastic rocks; may include fine-grained non-calcareous clastic rocks</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>12</edomv>
						<edomvd>marble; may include some calc-silicate rock</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>13</edomv>
						<edomvd>calcareous clastic and metaclastic rocks containing approximately 15 to 45% carbonate minerals</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>21</edomv>
						<edomvd>tan and red mudstone and shale; may include sandstone; locally contains minor carbonate or gypsum</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>22</edomv>
						<edomvd>interbedded mudstone, shale, and siltstone; may contain sandstone</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>23</edomv>
						<edomvd>sandstone and interbedded sandstone and conglomerate; may contain siltstone, shale, and mudstone</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>31</edomv>
						<edomvd>slate and graywacke</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>32</edomv>
						<edomvd>pelitic schist and phyllite, may include granofels</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>33</edomv>
						<edomvd>mixed schist, granofels; and gneiss</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>34</edomv>
						<edomvd>quartzose metasandstone, quartzite, quartz granofels, and quartzose gneiss</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>41</edomv>
						<edomvd>basalt</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>42</edomv>
						<edomvd>greenstone, lower greenschist facies metabasalt, and schistose mafic rock with minor dispersed carbonate (Mg-rich)</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>43</edomv>
						<edomvd>amphibolite and layered mafic gneiss; may be mixed with other lesser lithologies such as felsic volcanics and metaclastic rocks</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>44</edomv>
						<edomvd>massive mafic rocks; includes gabbro, diorite, monzodiorite, and diabase</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>45</edomv>
						<edomvd>mafic gneiss</edomvd>
					</edom>
					<edom>
						<edomv>50</edomv>
						<edomvd>ultramafic rocks; includes serpentinites, dunites, peridotites, and tremolite-talc schists associated with other ultramafic rocks</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>61</edomv>
						<edomvd>granitoid rocks; includes granite, quartz monzonite, granodiorite, trondhjemite, and equivalent gneiss</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>62</edomv>
						<edomvd>quartz-poor plutonic rocks; includes syenite, monzonite, quartz syenite, and anorthosite</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
					<edom>
						<edomv>70</edomv>
						<edomvd>nepheline syenite; includes feldspathoid-bearing syenitic rocks and volcanic rocks</edomvd>
						<edomvds>USGS Open-File Report 97-154</edomvds>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">R_GPB_ID</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">12</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">LITHO_CODE</attrlabl>
				<attrdef>
Lithogeochemical classification code, developed for this
data set that further subdivides the lithogeochemial groups
based on the presence of carbonate and(or) sulfide mineral
or on the relative age of the bedrock unit.
</attrdef>
				<attrdomv>
					<edom>
						<edomv>u</edomv>
						<edomvd>unit is undifferentiated</edomvd>
					</edom>
					<edom>
						<edomv>c</edomv>
						<edomvd>unit may contain small or variable amounts of carbonate minerals</edomvd>
					</edom>
					<edom>
						<edomv>cs</edomv>
						<edomvd>unit may contain small or variable amounts of carbonate minerals and minor amounts of pyrite, pyrrhotite, or both</edomvd>
					</edom>
					<edom>
						<edomv>g</edomv>
						<edomvd>unit contains variable amounts of graphite or organic materials</edomvd>
					</edom>
					<edom>
						<edomv>gc</edomv>
						<edomvd>unit may contain variable amounts of carbonate minerals and organic materials</edomvd>
					</edom>
					<edom>
						<edomv>gs</edomv>
						<edomvd>unit may contain minor amounts of pyrite, pyrrhotite, or organic materials, sufficient to cause a rusty-weathering characteristic.</edomvd>
					</edom>
					<edom>
						<edomv>s</edomv>
						<edomvd>unit may contain minor amounts of pyrite, pyrrhotite, or both</edomvd>
					</edom>
					<edom>
						<edomv>v</edomv>
						<edomvd>felsic volcanics associated within granite intrusions</edomvd>
					</edom>
					<edom>
						<edomv>n</edomv>
						<edomvd>nepheline-bearing syenite</edomvd>
					</edom>
				</attrdomv>
				<attalias Sync="TRUE">LITHO_CODE</attalias>
<attrtype Sync="TRUE">Double</attrtype>
<attwidth Sync="TRUE">8</attwidth>
<atprecis Sync="TRUE">18</atprecis>
<attscale Sync="TRUE">3</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">LITH_MOD</attrlabl>
				<attrdef>
Bedrock Unit label appearing on the state geologic map used as
the source for the lithogeochemical categorization.
</attrdef>
				<attrdomv>
					<codesetd>
						<codesetn>Lithologic units from state maps</codesetn>
						<codesets>File Bedrock.dbf in this data set</codesets>
					</codesetd>
				</attrdomv>
				<attalias Sync="TRUE">LITH_MOD</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">10</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">BEDROCK_1</attrlabl>
				<attrdef>
Bedrock unit codes characterized by state and including value for water bodies.
Except for surface waters, this field is the same as Bedrock_1.
</attrdef>
				<attrdomv>
					<edom>
						<edomv>Water</edomv>
						<edomvd>Inland freshwater body</edomvd>
					</edom>
					<codesetd>
						<codesetn>Lithologic units from state maps</codesetn>
						<codesets>File Bedrock.dbf in this data set</codesets>
					</codesetd>
				</attrdomv>
				<attalias Sync="TRUE">BEDROCK_1</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">30</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">BEDROCK_2</attrlabl>
				<attrdef>X coordinate of polygon label point in Albers projection</attrdef>
				<attrdomv>
					<rdom>
						<rdommin>-226338.73438</rdommin>
						<rdommax>317584.70835</rdommax>
						<attrunit>meters</attrunit>
					</rdom>
				</attrdomv>
				<attalias Sync="TRUE">BEDROCK_2</attalias>
<attrtype Sync="TRUE">String</attrtype>
<attwidth Sync="TRUE">30</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
			<attr>
				<attrlabl Sync="TRUE">SHAPE</attrlabl>
				<attrdef Sync="TRUE">Feature geometry.</attrdef>
				<attrdomv>
					<rdom>
						<rdommin>2002056.5</rdommin>
						<rdommax>2719492.875</rdommax>
						<attrunit>meters</attrunit>
					</rdom>
					<udom Sync="TRUE">Coordinates defining the features.</udom>
</attrdomv>
				<attalias Sync="TRUE">Shape</attalias>
<attrtype Sync="TRUE">Geometry</attrtype>
<attwidth Sync="TRUE">4</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
<attrdefs Sync="TRUE">ESRI</attrdefs>
</attr>
			<attr>
<attrlabl Sync="TRUE">SHAPE.AREA</attrlabl>
<attalias Sync="TRUE">SHAPE.AREA</attalias>
<attrtype Sync="TRUE">Double</attrtype>
<attwidth Sync="TRUE">0</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
<attr>
<attrlabl Sync="TRUE">SHAPE.LEN</attrlabl>
<attalias Sync="TRUE">SHAPE.LEN</attalias>
<attrtype Sync="TRUE">Double</attrtype>
<attwidth Sync="TRUE">0</attwidth>
<atprecis Sync="TRUE">0</atprecis>
<attscale Sync="TRUE">0</attscale>
</attr>
</detailed>
		<overview>
			<eaover>
The thirty-seven lithogeochemical units are defined for the New
England study region using an alpha-numeric identification: a
lithology code ("Litho_code", numeric) with a modifier code
("Lith_mod", alphabetic).

Example: Litho_code= "33" and Lith_mod= "cs"
Lithogeochemical unit is expressed as "33cs"

There are 20 lithology codes (including a code for water) that
represent rock type, metamorphic grade, and geologic setting.
Each bedrock unit is assigned one of 20 lithology codes based on
the description of the bedrock unit from the state bedrock
geologic maps.  Nine lithological modifier codes are used to
identify minor amounts of carbonate or sulfide minerals, and
subdivide granitic units into subgroups based on their chemical
and mineral characteristics.

The 37 lithogeochemical units are generalized into major rock
group categories (Rock_GpA and Rock_GpB).  Each category under
these headings shares similarities in overall geochemistry and
lithology. Rock Group A ("Rock_gpA") has 8 categories (including
one for freshwater).

Bedrock lithology information was obtained from
separate state source maps, and this results in some
discrepancies in rock group categories between polygons that meet
at state boundaries.  For example, a bedrock polygon that is
split into two polygons by a state border may be be categorized
as "Metamorphic Rocks Undivided" in one state and "Carbonate
Rocks" in the other state, based upon the different
characterization methods used by the originators of each of the
state geologic maps.  However, these discrepancies are relatively
few and do not interfere with the overall lithologic patterns of
the New England study area.

The eight major groups for Rock Group A are further divided into
Rock Group B. Rock Group B ("Rock_GpB") has 19 categories
(including one for freshwater). Each category has an ID code
("R_GpB_ID") that is used as a cross reference to other tabled
information.

Individual bedrock unit codes are designated by state from the
original state geologic maps used to create the digital
coverage (see references for source maps). Names and descriptions
for each bedrock code were gathered from source maps and are
provided in the associated file Bedrock.dbf. The "Bedrock_1"
attribute describes the alphanumeric code given to bedrock units
in the original state map sources (for example, "Trnh" or "Dw3A").
Some units have been combined (example "O-cr+O-cra") during the
digitizing process. "Bedrock_2" may further designate a polygon
as "water" if appropriate, but for  polygons not water bodies
"Bedrock_2" is the same as "Bedrock_1".

The bedrock units shown on the individual state maps for the New
England study region were classified according to a
lithogeochemical scheme modified from Robinson and others (1999).
Specifically, the modification included additional classification
into broad rock groups and the subdivision of granitic bedrock
units into subgroups based on age and magma chemistry, and the
addition of modifying attributes to indicate relative age.
However, this modification to the classification system is
evident in the lithogeochemical units.
</eaover>
			<eadetcit>
A detailed listing and descriptions of the 37 lithogeochemical
units is provided in
http://pubs.usgs.gov/of/2003/of03-225/unit-descriptions.html

Relationships among rock groups and between rock groups and
lithogeochemical units are shown in
http://pubs.usgs.gov/of/2003/of03-225/rock-groups.html

More detailed descriptions of each bedrock unit (grouped by the
state in which they occur) are provided in
http://pubs.usgs.gov/of/2003/of03-225/bedrock.dbf
</eadetcit>
		</overview>
	</eainfo>
	<distinfo>
		<distrib>
			<cntinfo>
				<cntperp>
					<cntper>Katherine E Kapo</cntper>
					<cntorg>U.S. Geological Survey, Eastern Minerals Resources Team</cntorg>
				</cntperp>
				<cntaddr>
					<addrtype>mailing address</addrtype>
					<address>
Mail Stop 954
12201 Sunrise Valley Drive
</address>
					<city>Reston</city>
					<state>VA</state>
					<postal>20192</postal>
					<country>USA</country>
				</cntaddr>
				<cntvoice>703 648-6103</cntvoice>
				<cntfax>703 648-6252</cntfax>
				<cntemail>kkapo@usgs.gov</cntemail>
			</cntinfo>
		</distrib>
		<resdesc>USGS Open-File Report 03-225</resdesc>
		<distliab>
Although these data have been used by the U.S. Department of the
Interior, U.S. Geological Survey, no warranty expressed or implied is
made by the U.S. Geological Survey as to the accuracy of the data.

The act of distribution shall not constitute any such warranty, and no
responsibility is assumed by the U.S. Geological Survey in the use of
this data, software, or related materials.  Any use of trade, product,
or firm names is for descriptive purposes only and does not imply
endorsement by the U.S. Government.
</distliab>
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					<cntper>Gilpin R Robinson</cntper>
					<cntorg>U.S. Geological Survey, ER</cntorg>
				</cntperp>
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Mail Stop 954
12201 Sunrise Valley Drive
</address>
					<city>Reston</city>
					<state>VA</state>
					<postal>20192</postal>
					<country>USA</country>
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<idCitation>
<resTitle Sync="TRUE">GISDATA.BEDROCKLITHOLOGY_POLY</resTitle>
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<idAbs>
This geographic information system (GIS) data layer shows the
dominant lithology and geochemical, termed lithogeochemical,
character of near-surface bedrock in the New England region
covering the states of Connecticut, Maine, Massachusetts, New
Hampshire, Rhode Island, and Vermont. The bedrock units in the
map are generalized into groups based on their lithological
composition and, for granites, geochemistry.  Geologic provinces
are defined as time-stratigraphic groups that share common features
of age of formation, geologic setting, tectonic history, and lithology.

This data set incorporates data from digital maps of two NAWQA
study areas, the New England Coastal Basin (NECB) and the
Connecticut, Housatonic, and Thames River Basins (CONN) areas and
extends data to cover the states of Connecticut, Maine,
Massachusetts, New Hampshire, Rhode Island, and Vermont.
The result is a regional dataset for the lithogeochemical
characterization of New England (the layer named NE_LITH).
Polygons in the final coverage are attributed according
to state, drainage area, geologic province, general rock type,
lithogeochemical characteristics, and specific bedrock map unit.
</idAbs><idPurp>
This geologic characterization provides a framework to interpret
regional geochemistry and habitat characteristics in relation to
bedrock lithology and geologic provinces that share common
features.  The lithogeochemical data layer combines and extends
data previously compiled for the U.S. Geological Survey National
Water Quality Assessment Program (NAWQA) study areas of the New
England Coastal Basin (NECB), and the Connecticut, Housatonic,
and Thames River Basins (CONN).  The coverage provides digital
geologic information that may be applied to the analysis of
water-quality characteristics of surface water and shallow ground
water, and soil and stream sediment characteristics based on
bedrock lithogeochemistry.

The geologic characterization provided in this classification is
intended to portray significant bedrock geologic features that
influence stream sediment and soil chemistry and water quality.

"Near-surface bedrock" in this report refers to lithified
materials covered by no more than about 60 feet of overlying
unconsolidated surficial materials.  The thickness of Quaternary
sediments overlying bedrock is generally less than 60 feet in
the New England states (Soller, 1993).

The bedrock units shown on the source maps were grouped and
generalized for this compilation.  Consequently this map
will show fewer geologic units and less detail than the
state geologic maps from which the information was drawn.

A few areas have been modified from those shown on the state
maps, for example, additional units portrayed by Smoot (1991) are
shown in the Hartford Basin area of Connecticut and Massachusetts
and mismatched contacts have been adjusted along state borders.

Based on the geologic map compilation scales, mismatches of some
unit contacts across state boundaries, and the positioneal
uncertainty of the source digital files relative to the published
geologic maps, the spatial accuracy of this compilation is
estimated as 1.5 km.

To the degree that surficial materials are related to their
proximal bedrock source, the variations in bedrock geology also
provide guidelines to the expected variation in the properties
and chemistry of surficial materials and surface waters. In
glaciated areas, such as New England, the mineralogy of tills and
some stratified drift is related to adjacent bedrock units, and
bedrock geology has been used to help define their chemical
character (Bailey and Hornbeck, 1992).  A lithogeochemical
framework similar to that provided in this report has been used
to define correlations between groundwater chemistry and bedrock
geology (Grady and Mullaney, 1988; Ayotte and others, 1999).
Groundwater chemistry for alkalinity, pH, Ca, Mg, Na, silica, and
radon in surficial aquifers sampled from wells up to 60 feet in
depth in surficial aquifers have been shown to correlate with
groups of lithology of the underlying bedrock (Grady and
Mullaney, 1988). Groundwater chemistry for pH, iron, manganese,
and arsenic in fractured crystalline bedrock aquifers sampled
from wells up to 500 feet in depth differ by bedrock lithology
groups (Ayotte and others, 1999; Ayotte and others, 2003).

The lithogeochemical characterization in these data have been
put to use analyzing water-quality characteristics in studies
by Grady and Mullaney (1998) and Ayotte and others (2003).
</idPurp><searchKeys><keyword>lithology</keyword></searchKeys></dataIdInfo>
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