| Table 4.
Stratigraphic and lithologic descriptions of monitoring
wells in Oasis Valley, Nevada [Stratigraphic unit: Qal, Quaternary alluvium; QTc, Quaternary and Tertiary colluvium; Tfc, Tuff of Cutoff Road, Tgs, Tertiary colluvial and alluvial gravel; Tma, Ammonia Tanks Tuff] |
Stratigraphic |
Depth interval |
Lithology |
Well ER-OV-01 |
||
"rhyolitic lavas of Colson Pond" |
0-68 |
Rhyolitic lava--bluish grey to grey brown; vitric |
do. |
68-90 |
Rhyolitic lava--grey; devitrified |
do. |
90-147 |
Rhyolitic lava and tuff--grey brown to red brown; moderately welded; pumiceous; devitrified(?); phenocrysts of quartz, plagioclase, and sanidine |
"tuff of Oasis Valley" |
147-180 |
Tuff--red brown to grey; moderately welded; pumiceous; hydrothermally altered; phenocrysts of plagioclase, quartz, sanidine, and biotite |
Well ER-OV-02 |
||
Qal |
0-52 |
Alluvium--thin (less than 1 foot) interbedded gravels, sands, and clays; well sorted; subrounded gravels |
QTc |
52-148 |
Colluvium--thick (greater than 2 feet) lenses of sandy, silty, and clayey gravels; angular to subangular, poorly sorted, moderately to well cemented gravels and cobbles |
Tgs |
148-200 |
Colluvium and alluvium--clay with rounded to angular fine gravel consisting of altered tuff(?) or rhyolitic lava(?); some Paleozoic clasts |
Well ER-OV-03a |
||
Qal |
0-35 |
Alluvium--sandy clayey gravels |
Tgs |
35-80 |
Colluvium and alluvium--thin (less than 1 foot) interbedded gravelly clays and sandy gravels; Paleozoic clasts |
Tfc |
80-130 |
Tuff--grey pink; densely welded |
Tma |
130-209 |
Tuff--grey pink; clayey; phenocrysts of quartz |
do. |
209-241 |
Tuff--grey pink; welded; phenocrysts of quartz |
do. |
241-251 |
Tuff--grey pink; clayey; phenocrysts of quartz |
Wells ER-OV-03a2 and ER-OV-03a3 |
||
Qal |
0-23 |
Alluvium--sandy clayey gravels |
Tfc |
23-75 |
Tuff--pink grey; phenocrysts of quartz; densely welded |
Tma |
75-133 |
Tuff--pink grey; moderately to densely welded; phenocrysts of quartz, biotite, and feldspars |
do. |
133-201 |
Tuff--pink grey to brown; moderately welded; phenocrysts of quartz, biotite, and feldspars; native sulfur crystals; highly fractured zone |
do. |
201-259 |
Tuff--pink grey; altered to clay; phenocrysts of quartz, biotite, and feldspars |
do. |
259-266 |
Fault gouge--brown clay; grey-pink tuff fragments |
do. |
266-310 |
Tuff--pink grey to pink brown; altered to clay; pink-grey tuff fragments; phenocrysts of quartz, biotite, and feldspars |
do. |
310-321 |
Fault gouge--red-brown clay |
do. |
321-821 |
Tuff--white, orange, tan, green, grey pink, and red; altered to clay; pumiceous; tuff fragments; basalt lithics; phenocrysts of quartz, biotite, sanidine, feldspars, and clinopyroxene |
Well ER-OV-03b |
||
Qal |
0-56 |
Alluvium--thin, unconsolidated, silty, sandy, and clayey gravels |
do. |
56-60 |
Playa deposits--evaporites interbedded with clay and very fine-grained silts and sands |
do. |
60-70 |
Alluvium--thin, unconsolidated, silty, sandy, and clayey gravels |
Tgs |
70-179 |
Colluvium and alluvium--clayey, sandy, very coarse gravels with scattered cobbles and boulders |
do. |
179-269 |
Alluvium--sandy, clayey gravels |
do. |
269-400 |
Alluvium--silty, clayey, coarse sand |
Well ER-OV-03c |
||
Qal |
0-32 |
Alluvium--thin, unconsolidated, clayey, sandy gravels |
Tma |
32-56 |
Tuff--orange to red clay; hydrothermally altered; fragments of unaltered tuff |
do. |
56-85 |
Tuff--red clay; hydrothermally altered |
do. |
85-520 |
Tuff--grey pink to grey; non to moderately welded; lithic fragments; ashy; vitrified; phenocrysts of quartz and feldspars |
do. |
520-542 |
Tuff--medium gray purple; densely welded; phenocrysts of quartz, feldspars, biotite, clinopyroxene |
Well ER-OV-03c2 |
||
Qal |
0-30 |
Alluviu--thin, unconsolidated, clayey, sandy gravels |
Tma |
30-87 |
Tuff--red clay; hydrothermally altered; fragments of unaltered tuff |
do. |
87-321 |
Tuff--grey pink to grey; non to moderately welded; lithic fragments; ashy; vitric; phenocrysts of quartz and feldspars |
Well ER-OV-04a |
||
Qal |
0-11 |
Alluvium--thin, unconsolidated, clayey, sandy gravels |
do. |
11-34 |
Alluvium--sandy gravels; moderately to well cemented |
do. |
34-151 |
Alluvium--silty, sandy gravels; non to moderately cemented; clay lenses |
Well ER-OV-05 |
||
Qal |
0-80 |
Alluvium--unconsolidated, silty, sandy gravels |
do. |
80-200 |
Alluvium--coarse gravels interbedded with silty, sandy clay |
Well ER-OV-06a |
||
"rhyolitic lavas of Colson Pond" |
0-325 |
Rhyolitic lava--bluish grey to grey brown; poorly to moderately welded; scattered hydrothermally altered stringers |
"tuff of Oasis Valley" |
325-431 |
Tuff--red brown to grey banded; poorly to moderately welded; pumiceous; hydro thermally altered; phenocrysts of plagioclase, quartz, and sanidine |
do. |
431-536 |
Tuff--tan to brown; moderately to densely welded; lithics |
Well ER-OV-06a2 |
||
"rhyolitic lavas of Colson Pond" |
0-71 |
Rhyolitic lava--bluish grey to grey brown; contains hydrothermally altered stringers |
