Generalized Geologic Map of the Upper Animas River Watershed and Vicinity, Silverton, Colorado

Online link https://geo-nsdi.er.usgs.gov/metadata/map-mf/2377/metadata.faq.html
Description This dataset represents geology compiled for the upper Animas River Watershed near Silverton, Colorado. The source data used are derived from 1:24,000, 1:20,000, 1:48,000 and 1:250,000-scale geologic maps by geologists who have worked in this area since
Originators Yager, Douglas B. and Bove, Dana J.
Publication U.S. Geological Survey Miscellaneous Field Studies Map MF-2377

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Overview of attributes

The data are supplied in ARC/INFO export format and in ArcView shapefile
format.
DATABASE STRUCTURE--The database structure of the map consists of seven coverages.
GEO coverage--Contains all contact lines and label points for each polygon.  The GEO.PAT INFO file has attribute fields for INFO ITEMS POLY-ID, NAME, COLOR, LITH, and AGE.  POLY-ID corresponds to a unique numeric polygon identifier that relates to each formation type; NAME corresponds to the formation name; COLOR corresponds to the ARC INFO colornames.shd symbolset number used for color shading; LITH corresponds to the unit litology, or rock type; AGE corresponds to the geologic age.
The GEO.AAT attributes are described below.
FAULTS coverage--Contains all lines, which represent faults and or combined fault and vein structures.  Some faults correspond with geologic contacts in the GEO coverage.  The FAULTS coverage has the attribute items LINE_ID and TYPE.  The attribute item in the ARC INFO file FAULTS.AAT contains the LINE_ID attribute, which has a number that corresponds with fault type, that is, concealed, inferred, and so forth; the TYPE field contains the fault type description.
VEINS coverage--Contains arcs for mineralized, altered veins and fissures.  The attribute item in the INFO file VEINS.AAT contains an ARC INFO ITEM fields LINE_ID and TYPE.  The LINE_ID contains a number that corresponds with vein type, that is, concealed vein, mineral fissure, and so forth; the TYPE field contains a description of the vein type.
A_DIKE coverage--Contains lines for dikes of andesitic(?) (52-68 percent SiO2) composition.
D_DIKE coverage--Contains lines for dikes of dacitic (63-68 percent SiO2) composition.
R_DIKE coverage--Contains lines for dikes of rhyolitic (>68 percent SiO2) composition.
SJCALD coverage--Contains lines that define the topographic margin of the San Juan caldera; the SJCALD.AAT attributes are described below.
The following detailed overview discusses all of the non common attributes included in each of the seven coverages that constitute the geologic map.
The GEO coverage includes the INFO files GEO.PAT and GEO.AAT.
The INFO file GEO.PAT has populated attribute fields for items POLY-ID, NAME, COLOR, LITH, and AGE.  POLY-ID is the unique numeric polygon code that corresponds to each formation type.  NAME is the formation name.  COLOR is the ARC INFO colornames.shd symbolset number used for color shading.  LITH is the unit lithology.  (Note--abbreviations are used for some unit LITH descriptions and they are as follows-siltst = siltstone, dol. = dolomite, sandst. = sandstone, calc. = calcareous, limest. = limestone, congl. = conglomerate, and mudst. = mudstone.)  AGE is the geologic age.
Attribute codes for all geologic units are defined in order of (POLY-ID,NAME,COLOR,LITH,AGE) as follows-
>(1,Tsp,60,rhyolite ash flow tuff,Miocene)
>(3,Qb,1,N.A.,Quaternary)
>(4,lake,21,N.A.,Quaternary)
>(7,Tcl,74,rhyolite ash flow tuff,Oligocene)
>(8,Ti,96,intrusions of unknown composition,Tertiary),
>(9,Qu,16,undifferentiated surficial deposits,Quaternary)
>(10,Qtg,17,talus,glacial till and rock glacier deposits,Quaternary)
>(11,Qal,6,unconsolidated fluvial deposits including alluvial fans, Quaternary)
>(12,Qcl,95,landslide and colluvium deposits,Quaternary)
>(19,Tir,118,rhyolite dikes and plugs,Miocene)
>(20,Tid,109,dacite intrusions,Oligocene to Miocene)
>(22,Tse,71,rhyolitic to dacitic ash flow tuff,Oligocene)
>(24,Ts,71,rhyolitic ash flow tuff,Oligocene)
>(25,Td,69,rhyolitic ash flow tuff,Oligocene)
>(27,Tb,68,rhyolitic ash flow tuff,Oligocene)
>(28,Tur,70,dacitic ash flow tuff,Oligocene)
>(29,Tig,25,monzonite to granodiorite stock,Oligocene)
>(30,Tsv,12,mostly intermediate comp. lava flows,volcaniclastics, Oligocene)
>(32,Tip,84,andesite to dacite ash flow tuff and breccia,Oligocene)
>(34,Tsj,24,mostly intermediate comp. volcaniclastics,lavas,Oligocene)
>(35,Tt,127,conglomerate and sandstone,Eocene)
>(36,Kg,113,granodiorite,Cretaceous)
>(37,Jm,65,sandstone and calcareous mudstone,Jurassic)
>(38,Je,58,sandstone,Jurassic)
>(39,Trd,49,siltst.,sandst., with limest.&congl. interbeds,Triassic)
>(40,Pc,36,shale,sandst.,&congl., locally calcareous,Permian)
>(41,Ph,23,sandst., with shale,sandst.,&congl.interbeds,Pennsylvanian)
>(42,Phm,30,shale, sandstone, and conglomerate,Pennsylvanian)
>(43,Pm,48,calcareous shale, sandstone, and conglomerate,Pennsylvanian)
>(44,Ml,36,limestone w. chert/shale interbeds (top),Mississippian)
>(45,Mdu,128,altered limestone,Mississippian)
>(45,Mdu?,128,altered limestone,Mississippian)
>(46,De,129,dol. limest., w. calc. shale & sandst. interbeds,Devonian)
>(48,Ci,52,quartzite,Cambrian)
>(49,pCu,121,schist,quartzite,and gneiss,Precambrian)
>(50,Do,93,dolomite and limestone,Devonian)
>(51,Jw,63,calc. mudst.&siltst., w. limest. sandst. interbeds,Jurassic)
>(52,Km,19,shale,Cretaceous)
>(53,Kd,20,sandst. w. siltst. & calc. shale interbeds,Cretaceous)
>(59,Tf,59,dacite ash flow tuff,Oligocene)
>(60,UM,2,Not mapped)
The INFO file GEO.AAT contains the attribute field LINE_ID, which in all cases is equal to "1" and which represents a solid contact.
The FAULTS coverage is comprised of the INFO file FAULTS.AAT.  FAULTS.AAT contains the attribute items LINE_ID and TYPE.  LINE_ID contains a number, which corresponds to a fault type; TYPE contains the description of the fault type. The LINE_ID = TYPE are described as follows--LINE_ID = 2, TYPE "Fault", LINE_ID = 8, TYPE "concealed or inferred fault".
The VEINS coverage is comprised of the INFO file VEINS.AAT.  VEINS.AAT contains the attribute items LINE_ID and TYPE.  LINE_ID contains a number,which corresponds to the vein type; TYPE contains the description of the vein type.  The LINE_ID = TYPE are described as follows--LINE_ID = 22, TYPE "Vein", LINE_ID = 23, TYPE "Mineral fissure", LINE_ID = 24, TYPE = "Concealed vein or fault".
The coverage A_DIKE (andesite dikes) includes the INFO FILE A_DIKE.AAT that has an attribute field LINE_ID; the LINE_ID = 5 in all instances.
The coverage D_DIKE (dacite dike) includes the INFO FILE D_DIKE.AAT that has an attribute field LINE_ID; the LINE_ID = 6 in all instances.
The coverage R_DIKE (rhyolite dike) includes the INFO FILE R_DIKE.AAT that has an attribute field LINE_ID; the LINE_ID = 4 in all instances.
The coverage SJCALD (San Juan caldera topographic margin) includes the INFO FILE SJCALD.AAT that has attribute fields LINE_ID and Type.  LINE_ID contains a number that corresponds to the topographic margin type.  The LINE_ID = TYPE are described as follows--LINE_ID = 14 indicates the topographic margin and LINE_ID = 15 is the concealed or approximately located topographic margin.

http://pubs.usgs.gov/mf/2002/mf-2377/mf-2377_508.pdf