<URL:http://water.usgs.gov/nawqa-only/gw.html>
This data set consists of surficial geology types for NAWQA sampling sites. The surficial geology data is from OFR 99-77. The sampling sites are from the NAWQA data warehouse.
This is one of the ancillary GIS data layers developed to characterize NAWQA sampling sites for national synthesis of water-quality data.
This data set excludes Alaska and Hawaii.
Intersected sampling points with Quaternary sediments attributes using IDENTITY. (March 2002 version of NAWQAPT.)
Intersected sampling points with Quaternary sediments attributes using IDENTITY. (July 2002 version of NAWQAPT.)
Intersected sampling points with Quaternary sediments attributes using IDENTITY. (July 2003 version of NAWQAPT.)
Intersected sampling points with Quaternary sediments attributes using IDENTITY. (March 2004 version of NAWQAPT.)
Intersected sampling points with Quaternary sediments attributes for thickness and character using IDENTITY. (May 2004 version of NAWQAPT.)
The data set is organized by STAID (station id).
The fields are:
STAID Station id GEOUNIT Surficial geology geounit GEOCODE Surficial geology geounit codeThe explanations for GEOCODE:
GEO GEOUNIT EXPLANATION
CODE
0 Null polygon
1 si Sea islands
2 cr Coral
3 bm Backshore deposits
4 pW Pre-Wisconsinan drift
5 tg Till, or ground moraine
6 ts Ice-laid deposits, like tg but mostly sand and silt
7 ts/K,T Thin ice-laid deposits, like ts but thin and discontinuous.
Extensive exposure of underlying Cretaceous- and
Tertiary-age formations
8 mg Deposits of mountain glaciers
9 w Gravel, sand and clay deposited by glacial streams adjacent to
or downstream from temporary ice fronts
10 al Floodplain and alluvium gravel terraces
11 fg Fan gravels
12 fs Fan sands
13 osg Pliocene-age and older stream deposits on the Great Plains
14 l Lake deposits
15 s Sand sheets, mostly with dunes or sand mounds at surface
16 s/osg Sand sheets on sandy and gravelly Ogallala Formation in
southern Great Plains
17 wl Wisconsinan loess
18 es Deeply weathered loess
19 b Basalt
20 br Bedrock
21 rsh Micaceous residuum without much quartz; clay,
mostly kaolinite
22 rgr Residuum with abundant quartz; much less mica than rsh, but
equal to clay
23 rga Clay residuum with little mica or quartz; mostly massive
kaolinitic clay
24 rls Red clay, massive clay that is generally kaolinitic
25 rlc Cherty red clay; similar to rls, but with chert from the
parent rock
26 rtr Residuum on Triassic-age formations; depths less than most
other saprolite, reddish color, largely inherited from
from parent rock
27 rs Sandy residuum, derived by intensive weathering of sandstone
formations. Sand locally is in dunes
28 rc Clay residuum that swells when wet; developed by weathering
of poorly consolidated shale, containing the clay mineral
montmorillonite, generally less than 10 feet
29 rl Loam; texture variable, ranging from sand to clay, mostly
non-swelling clay mineral, kaolinite; otherwise similar to rc
30 rg Intensively weathered upper Tertiary- and Quaternary-age
gravels; thickness generally less than 30 feet,
distribution not completely known
31 rph Phosphatic clay; poorly sorted clay and phosphate pebbles or
nodules in sandy matrix. Thickness 10 to 50 feet, commonly
overlain by loose sand. Major source of phosphate fertilizer
32 rsi Sandy or silty residuum; probably includes loess. Depth
generally less than 10 feet
33 ls Silt on limestone; probably includes considerable loess;
extensive bare rock
34 ss Sandy ground; mostly on poorly consolidated sandstone
formations
35 sh Shaley or sandy ground; on mixed sandstone and shale
formations; where shaley, contains considerable swelling clay
36 gyp Sandy gypsiferous ground; many sinks, local dunes; vegetation
scanty or lacking where there is much gypsum or other salt
37 c Clayey ground on weathered Permian- and/or Triassic-age
red beds
38 m Marshes, swamps, peat deposits; only locally thicker than 12
feet
39 gp Sandy coastal ground with organic layer over a shallow water
table, ground water podsols
40 co/ss,sh Sandy and stony colluvium derived mostly from sandstone and
shale
41 co/ls Stony colluvium on limestone; considerable admixed silt,
possibly of loess origin
42 co/m Stony colluvium on metamorphic rocks; less silt and clay than
in co/ls
43 co/v Colluvium on volcanic rocks
44 co/gr Bouldery and sandy colluvium on granitic rocks
45 co/c Clayey and loamy colluvium; on poorly consolidated rocks on
lee sides of Pacific Coast Ranges
kjhitt@usgs.gov
kjhitt@usgs.gov