Digital Geologic Map of the Penokean Continental Margin, Northern Michigan and Wisconsin

Online link https://geo-nsdi.er.usgs.gov/metadata/open-file/99-547/metadata.faq.html
Description The data on this CD consist of geographic information system (GIS) coverages and tabular data on the geology of Early Proterozoic and Archean rocks in part of the Early Proterozoic Penokean orogeny. The map emphasizes metasedimentary and metavolcanic rock
Originators Cannon, William F.
Publication U.S. Geological Survey Open-File Report 99-547

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pcmgeolg.pat

Polygon attribute table for pcgeo polygon coverage. The table contains attributes that address the following four catagories: 1.) STRATIGRAPHIC INFORMATION classifying geologic units according to stratigraphic position,2.) LITHOLOGIC INFORMATION providing three levels of detail (rock type, subtype, and lithology) to allow classification of rock types in both general and specific detail. The classification used is a draft classification scheme being developed by the USGS for digital portrayal of lithologic information. Information is provided for both the major lithologic type for each unit and as many as two additional significant lithologies, 3.) TECTONIC INFORMATION providing information on various aspects of the formation and deformation of units, and 4.) Fault type which classifies faults by type and age.

Label Definition
UNIT_NAME Name of the geologic units represented as polygons. Stratigraphic name for rock units. For layered rocks, generally corresponds to formation name.
MAP_SYMBOL A unique alphabetic symbol identifying each geologic unit as defined under the attribute "UNIT_NAME".
EXPLANATION A combination of Unit_name and Map_symbol
ERA The geologic era in which the rock unit formed. Not earned run average.
PERIOD The geological period in which the rock unit formed.
SUBPERIOD The geological subperiod in which the rock unit formed.
SUPERGROUP The stratigraphic supergroup to which a rock unit is assigned.
GROUP The stratigraphic group to which a rock unit has been assigned.
FORMATION/PLUTON The stratigraphic formation and igneous pluton to which a rock unit has been assigned.
MEMBER The geologic member to which a rock unit has been assigned
AGE Radiometric age or age range. Shown only for well constrained units.
MAJOR_ROCKTYPE The general lithologic classification for the most abundant rock type in a unit.
MAJOR_SUBTYPE The lithologic subtype for the most abundant rock type in a unit.
MAJOR_LITHOLOGY A specific lithologic name for the most abundant rock type in a unit.
MINOR_1_RK_TYPE The general lithologic classification for a less abundant rock type in a unit.
MINOR_1_SUBTYPE The lithologic subtype for a less abundant rock type in a unit.
MINOR_1_LITH A specific lithologic name for a less abundant rock type in a unit.
MINOR_2_RK_TYPE A specific lithologic name for a less abundant rock type in a unit
MINOR_2_SUBTYPE The lithologic subtype for a less abundant rock type in a unit.
MINOR_2_LITH A specific lithologic name for a less abundant rock type in a unit.
PROVINCE The geologic province to which a rock unit has been assigned.
TERRANE The geologic terrane to which a rock unit has been assigned.
SUBTERRANE The geologic subterrane to which a rock unit has been assigned.
PROVINCE_AGE Geologic age of province in which rock unit formed.
ORIGINAL_PROV Tectonic province in which older rocks were originally formed. Applied mostly to Archean rocks that were modified during Penokean orogeny.
ORIGINAL_SUBPROV Tectonic subprovince in which older rocks were originally formed. Applied mostly to Archean rocks that were modified during Penokean orogeny.
ORIG_PROV_AGE Original age of older rocks that have been modified during the Penokean orogeny.
ENVIRONMENT The physical environment in which the rock units were formed.
TECTONIC_SETTING The tectonic setting in which rock units were formed.
FAULT_TYPE A classification of faults by type and age. Penokean thrust- Major thrust faults formed during the Penokean orogeny. Most are boundaries between terranes or subterranes. All of the Penokean Thrust faults are north thrusting. Secondary Penokean thrust- thrust faults formed during the Penokean orogeny. Generally occur within a single subterrane. The Secondary Penokean Thrust Faults are variable in direction. Keweenawan thrust- thrust faults of Middle Proterozoic age related to the Midcontinent rift.The Keweenawan thrust faults are south thrusting. Faults with some Keweenawan displacement- faults with unclassified type of motion but which offset Keweenawan rocks as well as Early Proterozoic units. Some may be reactivated Penokean faults. Unclassified- faults for which information is insufficient to determine age or relative motion. Linear_ftrs- structure based on geophysical interpretation of buried terranes.