Bedrock Geology of Pennsylvania


Identification_Information:
Citation:
Citation_Information:
Originator: Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources
Publication_Date:2001
Title:
Bedrock Geology of Pennsylvania
Edition:1.0
Geospatial_Data_Presentation_Form:vector digital data
Publication_Information:
Publication_Place:Harrisburg, Pennsylvania
Publisher:Pennsylvania Bureau of Topographic and Geologic Survey
Online_Linkage: http://www.dcnr.state.pa.us/topogeo/map1/bedmap.aspx#entirestate
Description:
Abstract:
Two digital data sets, one for geologic units and faults and the other for dikes, have been
prepared for Pennsylvania. The data sets were digitized primarily from the artwork used
for the 1980 "Geologic Map of Pennsylvania" (Berg, T. M., Edmunds, W. E., Geyer,
A. R., and others, compilers, 1980, Geologic map of Pennsylvania: Pennsylvania
Geological Survey, 4th ser., Map 1, scale 1:250,000) and from source materials used for
that map. Many of the source materials had been published as page-sized maps and were
digitized from this published paper copy (Berg, T. M., and Dodge, C. M., 1981, Atlas of
preliminary geologic quadrangle maps of Pennsylvania: Pennsylvania Geological Survey,
4th ser., Map 61, scale approx. 1:62,500). The other source materials consist of
unpublished and published maps at various scales. It was beyond the scope of the project
to incorporate revisions that had been made to the geologic units since the 1980 map was
compiled; however, some updates to formational contacts, faults, and dikes, as well as to
geologic nomenclature and ages, were incorporated where the revisions could be easily
made.

The 1980 Pennsylvania state geologic map (Berg and others, 1980) shows the areal
distribution of 194 bedrock geologic units. The units range in geologic age from
Quaternary to Precambrian and encompass a wide variety of lithologies. The map was
compiled and published in a transverse mercator projection at 1:250,000 scale. The two
digital data sets include 195 geologic units, which, for the most part, closely correspond to
those shown on the 1980 map. The data sets were prepared using ArcInfo software and
are provided in a geographic coordinate system (units in decimal degrees). Although it is
possible to portray digital data at any scale, the geologic formational contacts, faults, and
dikes represented in these data sets are not intended to be used at any scale finer than
1:250,000.

The polygon attributes in the data set for geologic contacts and faults include unit number, map symbol, name, age, and three lithology categories that represent the general lithologic makeup of each geologic unit. Each arc (line) in the data set is attributed as one or more of the three general categories of contact, fault, or border. Contact lines are attributed according to the type of contact shown on the 1980 map (solid, dashed, queried, or arbitrary). Fault lines are similarly attributed (solid, dashed, or queried). Borders are attributed as either state boundaries, quadrangle boundaries, or the shoreline of Lake Erie. The data set for dikes consists of arcs attributed with unit number, map symbol, name, age, lithology, and type of dike (solid or dashed).

It is anticipated that the digital data sets will be used for a variety of regional or statewide geographic-information-system applications, including water-resource and environmental studies, conservation and ecosystem management, mineral exploration, and regional land use planning and development.

Purpose:
The hard-copy "Geologic Map of Pennsylvania" (Berg and others, 1980) is the most current, available source showing the bedrock geology of the entire state and has had widespread use for regional studies. The Pennsylvania Bureau of Topographic and Geologic Survey (PaGS), responding to numerous requests from federal and state government agencies and the private sector, has converted the geology represented on the 1980 map to a digital format. The purpose is to make the geology of the state available as a "seamless" coverage for use in regional spatial analyses and other digital applications.
Supplemental_Information:
The data sets are not intended to be used for detailed or site-specific analyses, nor are
they intended to be used at any scale finer than 1:250,000 (for example, use at
1:24,000 scale is inappropriate).
Time_Period_of_Content:
Time_Period_Information:
Single_Date/Time:
Calendar_Date:2001
Currentness_Reference:
Compilation or publication date of the source materials (see
separate file entitled <A HREF="credits.pdf">credits.pdf</A>)
Status:
Progress:Complete
Maintenance_and_Update_Frequency:Unknown
Spatial_Domain:
Bounding_Coordinates:
West_Bounding_Coordinate:-80.5196
East_Bounding_Coordinate:-74.6899
North_Bounding_Coordinate:42.2698
South_Bounding_Coordinate:39.7196
Keywords:
Theme:
Theme_Keyword_Thesaurus:ISO 19115 Topic Categories
Theme_Keyword:Geology
Theme_Keyword:Geologic map
Theme_Keyword:Bedrock geology
Theme_Keyword:Areal geology
Theme_Keyword:Surface geology
Theme_Keyword:Geologic units
Theme_Keyword:Formations
Theme_Keyword:Formational contacts
Theme_Keyword:Faults
Theme_Keyword:Dikes
Theme_Keyword:Lithologies
Theme_Keyword:Rock types
Theme_Keyword:Quaternary
Theme_Keyword:Tertiary
Theme_Keyword:Cretaceous
Theme_Keyword:Jurassic
Theme_Keyword:Triassic
Theme_Keyword:Permian
Theme_Keyword:Pennsylvanian
Theme_Keyword:Mississippian
Theme_Keyword:Devonian
Theme_Keyword:Silurian
Theme_Keyword:Ordovician
Theme_Keyword:Cambrian
Theme_Keyword:Lower Paleozoic
Theme_Keyword:Precambrian
Theme_Keyword:geoscientificinformation
Theme_Keyword:geoscientificinformation
Place:
Place_Keyword_Thesaurus:None
Place_Keyword:Pennsylvania
Place_Keyword:Allentown 30- by 60-minute quadrangle
Place_Keyword:Ashtabula 30- by 60-minute quadrangle
Place_Keyword:Bradford 30- by 60-minute quadrangle
Place_Keyword:Carlisle 30- by 60-minute quadrangle
Place_Keyword:Clearfield 30- by 60-minute quadrangle
Place_Keyword:Cumberland 30- by 60-minute quadrangle
Place_Keyword:East Liverpool 30- by 60-minute quadrangle
Place_Keyword:Erie 30- by 60-minute quadrangle
Place_Keyword:Hagerstown 30- by 60-minute quadrangle
Place_Keyword:Harrisburg 30- by 60-minute quadrangle
Place_Keyword:Honesdale 30- by 60-minute quadrangle
Place_Keyword:Indiana 30- by 60-minute quadrangle
Place_Keyword:Jamestown 30- by 60-minute quadrangle
Place_Keyword:Johnstown 30- by 60-minute quadrangle
Place_Keyword:Middletown 30- by 60-minute quadrangle
Place_Keyword:Monticello 30- by 60-minute quadrangle
Place_Keyword:Morgantown 30- by 60-minute quadrangle
Place_Keyword:Moundsville 30- by 60-minute quadrangle
Place_Keyword:Oil City 30- by 60-minute quadrangle
Place_Keyword:Pittsburgh East 30- by 60-minute quadrangle
Place_Keyword:Pittsburgh West 30- by 60-minute quadrangle
Place_Keyword:Reading 30- by 60-minute quadrangle
Place_Keyword:Scranton 30- by 60-minute quadrangle
Place_Keyword:State College 30- by 60-minute quadrangle
Place_Keyword:Sunbury 30- by 60-minute quadrangle
Place_Keyword:Towanda 30- by 60-minute quadrangle
Place_Keyword:Trenton 30- by 60-minute quadrangle
Place_Keyword:Tyrone 30- by 60-minute quadrangle
Place_Keyword:Warren 30- by 60-minute quadrangle
Place_Keyword:Wellsboro 30- by 60-minute quadrangle
Place_Keyword:Williamsport East 30- by 60-minute quadrangle
Place_Keyword:Williamsport West 30- by 60-minute quadrangle
Place_Keyword:Wilmington 30- by 60-minute quadrangle
Place_Keyword:York 30- by 60-minute quadrangle
Place_Keyword:Youngstown 30- by 60-minute quadrangle
Access_Constraints:None
Use_Constraints:
The data for the geologic units, faults, and dikes may be used provided that credit for the
original (unaltered) data sets is given to the Pennsylvania Bureau of Topographic and
Geologic Survey, Department of Conservation and Natural Resources. Users shall clearly
indicate the source of the data. Users who modify the data in any way are obligated to
describe the types of modifications they have made, including modifications to hard-copy
maps. Users are not to misrepresent Pennsylvania Bureau of Topographic and Geologic
Survey (PaGS) data sets, nor to imply that changes they (users) have made were approved
by the PaGS.<P>

These data sets are not designed for use as a primary regulatory tool in permitting and siting
decisions. This is public information and, as such, it may be used a reference source and
may be interpreted by organizations, agencies, units of government, or others based on
needs; however, each user is responsible for the appropriate application of the data.
Federal, state, or local regulatory bodies are not to reassign to the Bureau of Topographic
and Geologic Survey any authority for the decisions they make using these data sets.
<P>
The geologic units depicted on the published map are, in many cases, taken from source
maps that were based on aerial photograph interpretation and limited, or no, field checking.
Users are cautioned that, because of the nature and scale of the compilation and the source
materials used, the geologic contacts, faults, and dikes may be off their true locations by
several hundred feet locally. Users are also cautioned that, because the lithologies of many
geologic units vary widely both laterally and vertically, the representation of the lithology of
the geologic units based only on the dominant lithology (LITH1 in the polygon attribute
table) is in many cases inappropriate, even at a regional scale.
<P>
The data sets are not meant for site-specific analysis or for use at finer (i.e., larger, more
detailed) scales. Users are not to misrepresent the data sets by presenting them at scales for
which they are not intended, nor to imply that presentation at such scales is approved by the
PaGS.
<P>
The data sets are not to be redistributed for profit.
Please refer to the section on <A HREF="#Distribution_Liability">Distribution_Liability</A> for additional constraints.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person:Christine E. Miles
Contact_Organization: Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources
Contact_Address:
Address_Type:Mailing address
Address:
Bureau of Topographic and Geologic Survey, P. O. Box 8453
City:Harrisburg
State_or_Province:Pennsylvania
Postal_Code:17105-8453
Country:USA
Contact_Voice_Telephone:717-783-5812
Contact_TDD/TTY_Telephone:1-800-654-5984 (TDD) Pa. AT&amp;T relay service
Contact_Facsimile_Telephone:717-783-7267
Contact_Electronic_Mail_Address:miles.christine@dcnr.state.pa.us
Hours_of_Service:8:00 a.m.-5:00 p.m., Monday-Friday
Data_Set_Credit:
Geologic contacts, faults, and dikes are primarily from Berg and others (1980) and Berg
and Dodge (1981); however, several other sources were also used, which cannot be
efficiently documented in this format. Users are referred to <A HREF="credits.pdf">credits.pdf</A> for a list, by 7.5-
minute quadrangle, of sources of geologic maps used to prepare the data sets and
credits for the geologic work; to <A HREF="references.pdf">references.pdf</A> for complete bibliographic citations for
the sources; and to <A HREF="changes.pdf">changes.pdf</A> for an explanation of the global revisions that were
made to the geologic units, ages, and nomenclature from those shown on the 1980
map.
<P>
Lithology designations are modified from Berg and others (1980), based on reviews
by Rodger T. Faill and other staff geologists of the Bureau of Topographic and Geologic
Survey (PaGS) in 1998 and 2000.
<P>
Data sets of geologic units prepared from the 1980 map in the late 1980's and early 1990's
by the U.S. Geological Survey, Water Resources Division, were initially used by the PaGS
but were extensively revised and, in many places, completely redigitized during the course
of the project.
<P>
The assistance of Robert C. Smith, II, and Rodger T. Faill, both of the PaGS, in resolving
several geologic questions and problems that arose during the digital work is acknowledged
with appreciation.
<P>
Specific digital work (scanning, georeferencing, digitizing, attributing, and proofing) is
documented by 7.5-minute quadrangle in <A HREF="credits.pdf">credits.pdf</A>. General digital work (i.e., not
specific to quadrangles) is as follows. Elizabeth M. Stone, Jason M. Taylor, and
Rebecca A. Fox (student interns) assisted with general scanning, georeferencing, and
digitizing tasks in the early part of the project. Color tables for the map units in the
data set were prepared by Thomas G. Whitfield, Elizabeth M. Stone, and Christine E.
Miles. Annotation (labeling) of the map units was done by John G. Kuchinski. Most
final proofing of the data sets was by Christine E. Miles, with some assistance by
Thomas G. Whitfield and Darren A. Szuch (student intern). Macros for polygons
were prepared by Christine E, Miles and Thomas G. Whitfield, with assistance from
Jason M. Taylor, Erika M. Ballerstein, and Darren A Szuch (student interns); macros
for arcs were prepared by Christine E. Miles. Metadata (this document) and some
accompanying files (<A HREF="changes.pdf">changes.pdf</A> and <A HREF="polyattrib.pdf">polyattrib.pdf</A>) are by Christine E. Miles. Credits
and the associated reference list (<A HREF="credits.pdf">credits.pdf</A>, and <A HREF="references.pdf">references.pdf</A>) are by Christine E.
Miles and Thomas G. Whitfield. The map explanation (<A HREF="explanation.pdf">explanation.pdf</A>) was compiled
by Christine E. Miles. Web data files ad descriptions were prepared by Christine E. Miles.
Native_Data_Set_Environment:
Dell OptiPlex GXpro 200 workstation, Dell Workstation 400, and Dell Precision 410 workstation running Windows NT version 4.0 and NT ArcInfo versions 7.1.2 and 8.0.2; and Sun SPARCstation IPX workstations running SunOS version 5.5.1 (Solaris Open Windows version 3.5.1) and UNIX ArcInfo version 7.1.2, Patch 1.
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Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
The published geologic map (Berg and others, 1980) and source materials used for that
map (Berg and Dodge, 1981, and others listed in <A HREF="credits.pdf">credits.pdf</A> and <A HREF="references.pdf">references.pdf</A>) were the
basis for the polygon and arc attributes, except as follows: (1) lithology attributes of some
units were modified in the data sets from the lithologies listed in the explanation of the
1980 map, based on reviews in 1998 and 2000 by R. T. Faill and other geologists in the
Geologic Mapping Division of the Bureau of Topographic and Geologic Survey (PaGS);
(2) nomenclatural and age changes were made to some units, as described in <A HREF="changes.pdf">changes.pdf</A>;
and (3) revisions were made to some geologic units, based on more recent (post-1979)
mapping and/or current usage of the PaGS, as described in the "Updates" column in
<A HREF="credits.pdf">credits.pdf</A>. Such updates were done only where revisions could be easily made; systematic
and comprehensive updates were beyond the scope of the project.
<P>
Attributes were reviewed by staff of the PaGS by (1) comparing check plots with the
source maps; (2) visually checking attributes on a display of the map data on a computer
workstation; (3) checking printouts of the attributes; and (4) running a macro to ensure
correctness and consistency of polygon attributes. Based on these reviews, the attributes
are believed to be accurate.
Logical_Consistency_Report:
Complete chain-node topology is present. The data sets were checked for polygon closure,
erroneous or duplicate arcs, incorrect intersections, overshoots and undershoots, label
errors, node errors, and appropriate fuzzy tolerances.
Completeness_Report:
The data sets represent the regional bedrock geology of Pennsylvania. The bedrock geology
maps from which the contacts, faults, and dikes in these data sets were derived show the
rock units that crop out at the surface or that are present beneath the soil or beneath
relatively thin surficial deposits. The contacts of the soils themselves, or of surficial deposits
such as alluvium and colluvium, are not included in the source materials, nor are they
included in these data sets. There are, however, four geologic units on the 1980 map and in
the data set that are not lithified: the Quaternary sands of Presque Isle (Qs) and Trenton
Gravel (Qt); and the Tertiary Pensauken and Bridgeton Formations, undifferentiated (Tpb),
and Bryn Mawr Formation (Tbm).
<P>
Because the data sets represent regional geology, some of the bedrock geologic units are
(1) generalized, (2) combined with other units, or (3) slightly exaggerated in areal extent so
that they may be represented at 1:250,000 scale (the scale of the 1980 map and the scale of
accuracy of the data sets).
<P>
The faults and dikes are also generalized. As in the source maps from which they were
digitized, the faults show offsets of map units as well as the regional structural grain, but
they are not identified by name or by type (e.g., thrust, normal, or strike-slip).
<P>
The data sets do not include all of the information shown on the 1980 geologic map. For
example, the data sets do not contain inset maps, marginal type, cross sections, and the base
information, such as roads, streams, and political boundaries, shown on that map.
<P>
The lithologies in the polygon attribute table in the data set for geologic units and faults
(items LITH1, LITH2, and LITH3) were modified from the geologic descriptions of the
units in the map explanation of the 1980 map, based on reviews in 1998 and 2000 by
PaGS staff geologists. The scope of the 1980 map did not include the mapping of
lithologies, but rather the mapping of geologic formations which, in most cases, consist of
more than one lithology. The lithologic designations in the explanation of the 1980 map are
generalized and are not based on detailed field mapping or statistical analyses. Moreover,
the lithologies of many geologic units vary considerably both laterally and vertically.
Therefore, the dominant lithology (volumetrically) assigned to a given unit in the data set
may constitute only a minor part of that unit in local areas. Additionally, the lithologies
designated for each unit are generalized based on the areal extent of the unit within the
entire state. In cases where a geologic unit contains members and other subunits that are
present in only one region of the state, the lithologies for those subunits and members are
applied to all polygons designated as that unit, regardless of the region in which the
lithology occurs. For example, the Trimmers Rock Formation (Dtr) includes black shale of
the Harrell Formation at its base in the Susquehanna Valley, so black shale is included as a
lithology in the LITH3 category for all polygons in the state designated as Trimmers Rock
Formation, even though the Harrell Formation is not present in the northeast.
Positional_Accuracy:
Horizontal_Positional_Accuracy:
Horizontal_Positional_Accuracy_Report:
The horizontal positional accuracy of the data is that of the 1980 "Geologic Map of
Pennsylvania," which was compiled and published at 1:250,000 scale. The base map
on which the 1980 map was compiled is derived from U.S. Geological Survey 1- by 2-
degree quadrangles, which meet National Map Accuracy Standards for their scale of
1:250,000. The difference in positional accuracy between the locations of the geologic
contacts, faults, and dikes in the field and their digitized map locations is not known;
however, because of the nature of the compilation and the source materials used, the
digitized locations may be off the true field locations by several hundred feet locally.
Lineage:
Process_Step:
Process_Description:
Stable-base blackline mylar prints were prepared of the geologic contact and fault lines
from artwork that was used to publish the 1980 state geologic map (Berg and others,
1980). Latitude/longitude crosshairs were manually placed on the mylar prints at 15-
minute intervals using the latitude/longitude ticks from the base map of the 1980 geologic
map as a guide for positioning. The latter base map had been mosaicked in two sheets,
each having two overlays (drainage features and cultural features), from stable-base mylar
prints of the U.S. Geological Survey (USGS) standard series 1:250,000-scale 1- by 2-
degree quadrangle maps.
<P>
The blackline mylar prints were scanned, converted to grids using ArcInfo software, and
georeferenced. In an attempt to match as closely as possible the projection of the USGS
1- by 2-degree quadrangle maps that were used as the base for the 1980 map, the
georeferenced grid was projected to transverse mercator using the following parameters:
Projection: Transverse
Units: meters
Spheroid: Clarke1866
Parameters:
1.00000/*scale factor at central meridian
-77 45 0.000/*longitude of central meridian
40 52 30.000/*latitude of origin
0.00000/*false easting (meters)
0.00000/*false northing (meters)
<P>
The scanned image was compared on screen with vector files for roads and streams
imported from USGS standard 1:100,000-scale digital-line-graph (DLG) files. This
comparison, as well as subsequent check plots, revealed that there were inherent
problems and inconsistencies in the 1:250,000-scale base map used for the 1980 geologic
map that made it difficult to obtain proper alignment of geologic contacts with streams
and roads in the georeferenced digital data set. To obtain additional control, the source
maps drawn by the compilers of the 1980 map were examined. These source maps
contained the same geologic units shown on the 1980 map, but were drawn on paper 7.5-
minute or 15-minute quadrangle base maps, many of which had been transcribed and
published at page size in Berg and Dodge (1981). The page-sized 7.5-minute quadrangle
maps were scanned, converted to grids, and georeferenced using the latitude and
longitude at the four corners of each quadrangle for control. Following projection to
transverse mercator, the roads and streams on the images of the page-sized source maps
were compared on screen to the roads and streams from the USGS 1:100,000-scale DLG
files. Most roads and streams from the DLG files fit those shown on the scanned images
of the source maps to within 60 meters; thus, the page-sized source maps were considered
to be good control for determining the placement of the geologic contacts at 1:250,000
scale.
<P>
Other source materials, including some containing updates and changes to the geology
shown on the 1980 map, were similarly scanned and georeferenced (see <A HREF="credits.pdf">credits.pdf</A> for a
list of sources scanned for each quadrangle).
Process_Date:1997-2000
Process_Step:
Process_Description:
Using the projected grids described in the step above as background images, the data set
for geologic contacts prepared by the USGS-WRD in the late 1980's and early 1990's
was edited on screen so that the polygons fit the locations shown on the scanned image.
This process, as well as subsequent processes described below, required editing or
redigitizing every arc and polygon in the data set. Label points were also moved where
necessary so that they remained inside the appropriate polygons following editing of the
arcs. Fault lines were added to the data set. The state boundary of the USGS-WRD data
set was deleted and replaced with a state boundary compiled from the USGS standard
1:100,000-scale DLG files for boundaries.
<P>
The separate data set for dikes was prepared entirely by the PaGS using the scanned,
georeferenced images from Berg and Dodge (1981) and other sources cited in <A HREF="credits.pdf">credits.pdf</A>.
The arcs in the coverage were attributed with unit number, map symbol, name, age, and a
lithology designation.
<P>
To conform to the regional scale of the compilation (1:250,000), tightly curved contacts on
the source maps were generalized in the data set and units of small areal extent were
exaggerated, but the generalization on the whole is less than that on the 1980 map. The
degree of exaggeration that was employed by the compilers of the 1980 map in regard to
the 1:250,000-scale base features (e.g., moving contacts away from roads and streams)
was, in most places, ignored when contacts were digitized from the source maps.
<P>
Five attributes (UNITNO, AGE, LITH1, LITH2, and LITH3) were added to the polygon attribute
table for geologic units and faults (pageo.pat), and the two polygon attributes
(FM and NAME) that had been included in the USGS-WRD data set were redefined
(MAP_SYMBOL and NAME). Six attributes (CONTACT, FAULT, BORDER,
CONTACTLINE, FAULTLINE, and BORDERLINE) were added to the arc attribute
table (pageo.aat), and the attribute values were assigned to the arcs as part of the editing
process.
Process_Date:1998-2000
Process_Step:
Process_Description:
Following the extensive editing, redigitizing, and attributing of the polygons and arcs,
various check plots were prepared and proofread in order to verify the locational
accuracy of the lines and to check for errors in arc attributes and in labels of geologic
units. Additional checks for label and attribute errors were made on the computer
workstation.
<P>
A script was prepared in Arc Macro Language (AML) to ensure correctness and
consistency of polygon attributes. Using the script, the item "MAP_SYMBOL" was
selected for each polygon, and the correct attributes for UNITNO, NAME, AGE, LITH1,
LITH2, and LITH3 were calculated based on the map symbol.
<P>
After all corrections were made, the data sets were projected to new data sets in
a geographic coordinate system (units in decimal degrees). The latter data sets were
exported as ArcInfo export files (pageo.e00 and padike.e00) and were converted to
polygon and arc shapefiles (pagpoly.shp, pagarc.shp, padike.shp) using ArcView
software.
Process_Date: 1998-2000
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Spatial_Data_Organization_Information:
Direct_Spatial_Reference_Method:Vector
Point_and_Vector_Object_Information:
SDTS_Terms_Description:
Point_and_Vector_Object_Count: 26,909 STDS_Point_and_Vector_Object_Type: Node (data set for dikes)
Point_and_Vector_Object_Count:1,234
SDTS_Terms_Description:
Point_and_Vector_Object_Count: 36,699 STDS_Point_and_Vector_Object_Type: Complete chain (data set for dikes)
Point_and_Vector_Object_Count:649
SDTS_Terms_Description:
Point_and_Vector_Object_Count: 14,479
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Spatial_Reference_Information:
Horizontal_Coordinate_System_Definition:
Geographic:
Latitude_Resolution:Unknown
Longitude_Resolution:Unknown
Geographic_Coordinate_Units:Decimal degrees
Geodetic_Model:
Horizontal_Datum_Name:North American Datum of 1927
Ellipsoid_Name:Clarke 1866
Semi-major_Axis:6378206.4
Denominator_of_Flattening_Ratio: 294.98
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Entity_and_Attribute_Information:
Overview_Description:
Entity_and_Attribute_Overview:
In the data set for geologic units and faults, the entity type is a geologic unit as shown on
the 1980 state geologic map (Berg and others, 1980). Each geologic unit consists of a
sequence, group, formation, or member. The units are distinguished from each other by
geologic characteristics such as rock type, color, and texture, and are mappable at the scale
of 1:250,000. Units shown on the 1980 map are intended to be rock-stratigraphic (i.e.,
correlations shown or implied are rock correlations and may transgress time boundaries).

The polygon and line (arc) attribute items for the entity type of geologic unit are in
typical ArcInfo feature class format. Polygon attribute items (in table pageo.pat) are
as follows:

COLUMN  ITEM NAME     WIDTH     OUTPUT   TYPE    N. DEC.    INDEXED?

1     AREA             8        18       F         5         --
9     PERIMETER        8        18       F         5         --
17     PAGEO#           4         5       B        --         --
21     PAGEO-ID         4         5       B        --         --
25     UNITNO           4         4       I        --         --
29     MAP_SYMBOL      10        10       C        --         --
39     NAME           100       100       C        --         --
139     AGE             50        50       C        --         --
189     LITH1           35        35       C        --         --
224     LITH2           35        35       C        --         --
259     LITH3           85        85       C        --         --

Please note that the shapefile for polygons (pagpoly.shp) has the same items, but the "#"
symbol is changed to "_" in the conversion from the ArcInfo file.

Definitions of user-defined polygon attribute labels are as follows. Please refer to
<A HREF="polyattrib.pdf">polyattrib.pdf</A> for a complete list of attribute domain values for each item, and to
<A HREF="changes.pdf">changes.pdf</A> for a list of changes and updates made in the data sets to map symbols,
names, and ages from those shown on the 1980 state geologic map (Berg and others,
1980).

UNITNO: A unique number assigned to each map unit in the data set. The number,
which is not derived from the 1980 map, places the units approximately, but not
completely, in a sequence ranging from those having the youngest ages (lower
numbers) to those having the oldest ages (higher numbers). In the data set for geologic
units and faults, there are 193 unique unit numbers ranging from 1 to 195 (unit number
6, kimberlite, and unit number 15, Quarryville Diabase, occur only in the data set for
dikes).

MAP_SYMBOL: The symbol used to label the unit on the 1980 state geologic map,
except where modified as indicated in <A HREF="changes.pdf">changes.pdf</A>. Please note that the "double-bar
P" shown on the 1980 map to indicate units of Pennsylvanian age has been changed
to "P," the special character for Triassic units (capital "T" joined to small capital "R")
has been changed to "Tr,"and the special character for units of Cambrian age ("C"
with horizontal bar) has been changed to "C" in the attribute table.

NAME: The name of the geologic unit in the explanation of the 1980 state geologic
map (Berg and others, 1980), except where modified as indicated in <A HREF="changes.pdf">changes.pdf</A>.

AGE: The age of the geologic unit as shown on the 1980 state geologic map (Berg and
others, 1980), except where modified as indicated in <A HREF="changes.pdf">changes.pdf</A>. Ages are at the level
of a geologic period.

LITH1: The dominant lithology, volumetrically, in the rock unit. Lithologies were
modified from the geologic description in the map explanation of the 1980 state
geologic map (Berg and others, 1980), based on reviews by PaGS staff geologists in
1998 and 2000. The lithologies are assigned based on the entire areal extent of the
geologic unit within Pennsylvania; thus, all lithologies listed (particularly in the
LITH3 item) may not be present in local areas.

LITH2: The secondmost dominant lithology, volumetrically, in the map unit. See
LITH1 above for source.

LITH3: Other major lithologies, volumetrically, in the rock unit. See LITH1 above
for source.

The arc attribute items (in table pageo.aat) are as follows:

COLUMN  ITEM NAME     WIDTH     OUTPUT   TYPE    N. DEC.    INDEXED?

1     FNODE#           4         5       B        --         --
5     TNODE#           4         5       B        --         --
9     LPOLY#           4         5       B        --         --
13     RPOLY#           4         5       B        --         --
17     LENGTH           8        18       F         5         --
25     PAGEO#           4         5       B        --         --
29     PAGEO-ID         4         5       B        --         --
33     CONTACT          5         5       C        --         --
38     FAULT            5         5       C        --         --
43     BORDER           5         5       C        --         --
48     CONTACTLINE     30        30       C        --         --
78     FAULTLINE       30        30       C        --         --
108     BORDERLINE      15        15       C        --         --

Please note that the shapefile for arcs (pagarc.shp) has the same items, but the "#" symbol
is changed to "_" and "CONTACTLINE" has been truncated to "CONTACTLIN" in the
conversion from the ArcInfo file.

Definitions of user-defined arc attribute labels and attribute domain values are as follows:

CONTACT: Indicates whether the line is a contact (y, yes; n, no).

FAULT: Indicates whether the line is a fault (y, yes; n, no).

BORDER: Indicates whether the line forms the border of the data set (y, yes; n, no).

CONTACTLINE: The type of contact line between geologic units shown on the 1980
state geologic map. The types of contact lines (i.e., the attribute values) in the data set
for geologic units are as follows:

Solid: A contact line between two geologic units that is shown as a solid line on the
1980 map. Quantitative locational accuracy values are not known.

Dashed: A contact line between two geologic units that is shown as a dashed line on
the 1980 map. The location of a dashed contact line is more approximate than that
of a solid contact line. Quantitative locational accuracy values are not known.

Arbitrary: A contact line between geologic units that is shown as a color break only
(i.e., no line is shown) on the 1980 map. This type of contact typically occurs where
two or more geologic units are mapped separately on one side of the contact line and
are grouped together as one unit on the other side of the contact line. The units are
grouped either because (1) their individual unit areas are too small to be shown at the
scale of 1:250,000; or (2) the geology of the area has not been mapped in sufficient
detail to allow the units to be distinguished separately. An arbitrary contact line may
also represent a facies change (i.e., a lateral variation between sedimentary rocks that
were deposited during the same time period but in different sedimentary
environments). In such cases, the approximate area of the change from one unit to the
other is indicated by the arbitrary line. An arbitrary contact line is also used to bound
the Valentine Member of the Benner Formation, which is generalized on the 1980
map as a line of uniform width, and which is included in the data set as a polygon of
uniform width.

Queried: A contact line between two geologic units that is shown as a queried line
on the 1980 map or source materials used for that map. A queried line indicates that
the location of the contact is uncertain or questionable.

FAULTLINE: The type of fault line shown on the 1980 state geologic map. The types
of fault lines (i.e., attribute values) in the data set are as follows:

Solid: A fault line that is shown as a solid line on the 1980 map. Quantitative
locational accuracy values are not known.

Dashed: A fault line that is shown as a dashed line on the 1980 map. The location
of a dashed fault line is more approximate than that of a solid fault line. Quantitative
locational accuracy values are not known.

Queried: A fault line that is shown as a queried line on the 1980 map or source
materials used for that map. A queried line indicates uncertainty about the
existence of the fault.

BORDERLINE: A term used to define the type of line that generally forms the outer
boundary of the data set. The types of border lines (i.e., attribute values) in the data
set are as follows:

State: The Pennsylvania state boundary.

Quad: The boundary of a 30-by 60-minute quadrangle within Pennsylvania.
Lake Erie: The shoreline of Lake Erie.

In the data set for dikes, the entity type is a dike as shown on the 1980 state geologic map
(Berg and others, 1980). Although dikes are tabular features, because of the scale, they are
shown as lines on the 1980 map and have been digitized as lines (arcs) in the data set. The
arc attribute items (in table padike.aat) are as follows:

COLUMN  ITEM NAME     WIDTH     OUTPUT   TYPE    N. DEC.    INDEXED?

1     FNODE#           4         5       B        --         --
5     TNODE#           4         5       B        --         --
9     LPOLY#           4         5       B        --         --
13     RPOLY#           4         5       B        --         --
17     LENGTH           8        18       F         5         --
25     PADIKE#          4         5       B        --         --
29     PADIKE-ID        4         5       B        --         --
33     UNITNO           4         4       I        --         --
37     MAP_SYMBOL      10        10       C        --         --
47     NAME           100       100       C        --         --
147     AGE             50        50       C        --         --
197     DIKELINE        15        15       C        --         --
212     LITH1           35        35       C        --         --

Please note that the shapefile for arcs (padike.shp) has the same items, but the "#"
symbol is changed to "_" in the conversion from the ArcInfo file.

Definitions of user-defined dike attribute labels are as follows. Please refer to
<A HREF="dikeattrib.pdf">dikeattrib.pdf</A> for a complete list of attribute domain values for each item, and to
<A HREF="changes.pdf">changes.pdf</A> for a list of changes and updates made in the data sets to map symbols, names,
and ages from those shown on the 1980 state geologic map (Berg and others, 1980).

UNITNO: See definition of "UNITNO" in polygon attributes for the data set for
geologic units and faults above.

MAP_SYMBOL: The symbol used to label the dike on the 1980 state geologic map
(Berg and others, 1980), except where modified as indicated in <A HREF="changes.pdf">changes.pdf</A>.

NAME: The name of the geologic unit in the explanation of the 1980 state geologic
map (Berg and others, 1980), except where modified as indicated in <A HREF="changes.pdf">changes.pdf</A>.

AGE: The age of the geologic unit as shown on the 1980 state geologic map (Berg and
others, 1980), except where modified as indicated in <A HREF="changes.pdf">changes.pdf</A>.

DIKELINE: The type of line symbol used for the dike on the 1980 state geologic map.
The types of dike lines (i.e., attribute values) in the data set are as follows:

Solid: A dike line that is shown as a solid line on the 1980 map. Quantitative
locational accuracy values are not known.

Dashed: A dike line that is shown as a dashed line on the 1980 map. The location
of a dashed dike line is more approximate than that of a solid dike line. Quantitative
locational accuracy values are not known.

LITH1: The dominant lithology, volumetrically, in the rock unit. See source for
lithologies in definition of "LITH1" in the polygon attributes for the data set for
geologic units and faults above.
Entity_and_Attribute_Detail_Citation:
Berg and others (1980)
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Distribution_Information:
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Person_Primary:
Contact_Person:Christine E. Miles
Contact_Organization: Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources
Contact_Address:
Address_Type:Mailing address
Address:
Bureau of Topographic and Geologic Survey, P. O. Box 8453
City:Harrisburg
State_or_Province:Pennsylvania
Postal_Code:17105-8453
Country:USA
Contact_Voice_Telephone:717-783-5812
Contact_TDD/TTY_Telephone:1-800-654-5984 (TDD) Pa. AT&amp;T relay service
Contact_Facsimile_Telephone:717-783-7267
Contact_Electronic_Mail_Address:miles.christine@dcnr.state.pa.us
Hours_of_Service:8:00 a.m.-5:00 p.m., Monday-Friday
Distribution_Liability:
These data files and documentation are provided "as is," and the user assumes the entire
risk as to their quality and performance.
<P>
The Commonwealth of Pennsylvania makes no guarantee or warranty concerning the
accuracy of information contained in the geographic data or accompanying documentation.
The Commonwealth of Pennsylvania further makes no warrantees, either expressed or
implied, as to any other matter whatsoever, including, without limitation, the completeness
or condition of the product, or its fitness for any particular purpose. The burden for
determining fitness for use lies entirely with the user.
<P>
Although these data have been processed successfully on a computer system at the Bureau
of Topographic and Geologic Survey, the Commonwealth of Pennsylvania makes no
warranty, expressed or implied, regarding the use of the data files or accompanying
documentation on any other computer system, nor does the act of distribution constitute any
such warranty.
<P>
The user shall save the Commonwealth of Pennsylvania harmless from any suits, claims, or
actions arising out of the use of or any defect in the data files or accompanying
documentation.
<P>
The Commonwealth of Pennsylvania assumes no legal liability for the accuracy,
completeness, or usefulness of the data files and accompanying documentation. In no event
shall the Commonwealth of Pennsylvania have any liability whatsoever for payment of
any consequential, incidental, indirect, special, or tort damages of any kind, including, but
not limited to, any loss of profits arising out of use of or reliance on the geographic data.
<P>
Not for commercial resale.
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name:ArcInfo Export
Format_Name:Shapefiles for polygons and arcs, prepared using ArcView software
Format_Version_Number:8.0.2 (ArcInfo)
Format_Version_Number:3.2a (ArcView)
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name: http://www.dcnr.state.pa.us/topogeo/map1/bedmap.htm
Fees:Free
Ordering_Instructions:
Please refer to the instructions for downloading the files at the
site listed above. All users should download both the data and the metadata files.
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Metadata_Reference_Information:
Metadata_Date:20001222
Metadata_Review_Date:20001223
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person:Christine E. Miles
Contact_Organization: Pennsylvania Bureau of Topographic and Geologic Survey, Department of Conservation and Natural Resources
Contact_Address:
Address_Type:Mailing address
Address:
Bureau of Topographic and Geologic Survey, P. O. Box 8453
City:Harrisburg
State_or_Province:Pennsylvania
Postal_Code:17105-8453
Country:USA
Contact_Voice_Telephone:717-783-5812
Contact_TDD/TTY_Telephone:1-800-654-5984 (TDD) Pa. AT&amp;T relay service
Contact_Facsimile_Telephone:717-783-7267
Contact_Electronic_Mail_Address:miles.christine@dcnr.state.pa.us
Hours_of_Service:8:00 a.m.-5:00 p.m., Monday-Friday
Metadata_Standard_Name:Content Standard for Digital Geospatial Metadata
Metadata_Standard_Version:FGDC-STD-001-1998
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