denvpoly: polygon coverage containing geologic unit contacts and labels. denvline: arc coverage containing faults. geol_sfo.lin: This lineset file defines geologic line types in the geologically themed coverages. geoscamp2.mrk: This markerset file defines the geologic markers in the geologically themed coverages. color524.shd: This shadeset file defines the cmyk values of colors assigned to polygons in the geologically themed coverages.
DENVPOLY.PAT: COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 AREA 8 18 F 5 9 PERIMETER 8 18 F 5 17 DENVPOLY# 4 5 B - 21 DENVPOLY-ID 4 5 B - 25 SOURCE 4 4 I - 29 LABEL 10 10 C - 39 DESC 123 123 C - 162 SYMBOL 3 3 I - DENVPOLY.AAT: COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 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 DENVPOLY# 4 5 B - 29 DENVPOLY-ID 4 5 B - 33 NAME 30 30 C - 63 SOURCE 4 4 I - 67 SYMBOL 3 3 I - DENVPOLY.REF: COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 SOURCE 4 4 I - 5 SCALE 8 8 I - 13 AUTHORS 200 200 C - 213 YEAR 4 4 I - 217 REFERENCE 250 250 C - Unique values of NAME in DENVPOLY.AAT: contact, neat, waterdenvline coverage: contains faults. In the denvline.aat INFO file the NAME item indicates the name given to the structural feature.
DENVLINE.AAT: COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 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 DENVLINE# 4 5 B - 29 DENVLINE-ID 4 5 B - 33 NAME 30 30 C - 63 SOURCE 4 4 I - 67 SYMBOL 3 3 I - DENVLINE.REF: COLUMN ITEM NAME WIDTH OUTPUT TYPE N.DEC ALTERNATE NAME 1 SOURCE 4 4 I - 5 SCALE 8 8 I - 13 AUTHORS 200 200 C - 213 YEAR 4 4 I - 217 REFERENCE 250 250 C - Unique values of NAME in DENVLINE.AAT: High-angle reverse fault Database root name: denv LABEL AND DESCRIPTION FOR GEOLOGIC UNITS MAPPED LABEL DESC afa Alluvial-fan deposit cac Arkosic loamy colluvium and sheetwash alluvium cacb Bouldery phase of arkosic loamy colluvium xch Clayey, calcareous disintegration residuum dba Crystalline-clast deposits dbd Mixed-lithology-clast deposits asa Alluvial sand, silt, clay, and gravel (post-Piney Creek alluvium, Piney Creek Alluvium,and pre-Piney Creek alluvium ed Stabilized dune sand es Eolian sand jea Slump-block, earthflow, and mudflow landslide deposits ccd Calcareous clayey colluvium ccm Andesitic clayey colluvium caa Andesitic loamy colluvium clx Clay loam colluvium csk Grus, crystalline-clast colluvium, rock outcrop, and alluvium csm Tuffaceous colluvium cgc Gneiss- and granite-clast gravelly colluvium cgh Arkose-clast loamy colluvium cbh Blocky sedimentary-rock colluvium cbm Carbonate-clast loamy colluvium cbs Rhyolite- and andesite-clast colluvium cbu Mixed-lithology blocky colluvium xlu Feldspathic loamy disintegration residuum xlv Loamy disintegration residuum, eolian sand, and sheetwash alluvium xsa Feldspathic quartz-sand disintegration residuum xgb Latite-clast disintegration residuum jbc Bouldery crystalline-rock landslide deposit xsg Feldspathic quartz-sand disintegration residuum elb Loess (Peoria Formation) tbg Crystalline-clast bouldery till tbj Mixed-lithology-clast bouldery till ggq Outwash sand and gravel (outwash of Bull Lake, Pinedale, and post-Pinedale ages) ags Alluvial sand, silt, clay and gravel (Louviers and Slocum Alluviums, undivided; late middle Pleistocene) tbk Bouldery till (till of pre-Bull Lake glaciations) gge Outwash sand and gravel (outwash of pre-Bull Lake glaciations) agm Alluvium gravel and sand (Verdos and Rocky Flats Alluviums, undivided; early middle Pleistocene and early Pleistocene) pga Pediment gravel cra Hogback and rangefront colluvium, alluvium, and rock outcrop complex QTdd Diamicton R Bedrock w Open water
In 1978, Lucille A. Piety hand drafted a map of surficial geologic units for the Denver quadrangle. She accomplished this by generalizing linework from the published Geologic Map of the Denver 1°x2° quadrangle, north-central Colorado (Bruce Bryant, L.W. McGrew, and R.A. Wobus, 1981, USGS Miscellaneous Investigations Series Map I- 1163). This linework was intended to be reduced as partial input for a more extensive 1:1,000,000-scale map. We digitized these lines initially, edited them to obtain more detail and accuracy, and added data appropriate for a 1:250,000-scale published map. Piety also classified the surficial units. However, because this system was designed for a 1:1,000,000-scale map (less detailed map), we had to make a more detailed classification to replace it.
The map and descriptions offer information that may be used for: land-use planning (e.g. selecting land fill sites, greenbelts, avoiding geologic hazards), for finding aggregate resources (crushed rock, sand, and gravel), for study of geomorphology and Quaternary geology. Geologic hazards (e.g., landslides, swelling soils, heaving bedrock, and flooding) known to be located in, or characteristic of some mapped units, were identified.
Surficial deposits in the quadrangle partially record depositional events of the Quaternary Period (the most recent 1.8 million years). Some events such as floods are familiar to persons living in the area, while other recorded events are pre-historical. The latter include glaciation, probable large earthquakes, protracted drought, and widespread deposition of sand and silt by wind. At least twice in the past 200,000 years (most recently about 30,000 to 12,000 years ago) global cooling caused glaciers to form along the Continental Divide. The glaciers advanced down valleys in the Front Range, deeply eroded the bedrock, and deposited moraines (map units tbg, tbj) and outwash (ggq, gge). On the plains (east part of map), eolian sand (es), stabilized dune sand (ed), and loess (elb) are present and in places contain buried paleosols. These deposits indicate that periods of sand dune deposition alternated with periods of stabilized dunes and soil formation.
Are there legal restrictions on access or use of the data?
Use_Constraints:none. Acknowledgment of the U.S. Geological Survey would be appreciated in products derived from these data.
Any use of trade names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Although this digital spatial data has been subjected to rigorous review and is substantially complete, it is released on the condition that neither the USGS nor the United States Government may be held liable for any damages resulting from its authorized or unauthorized use.
|Data format:||Surficial geologic units in format ARCE (version 7.2.1) Size: 0.9|
|Data format:||Surficial geologic units in format Shapefile (version 1.0) Size: 0.9|