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Paleohydrologic record of spring deposits in and around Pleistocene pluvial Lake Tecopa, southeastern California

GSA Bulletin

By:
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DOI: 10.1130/0016-7606(2001)113<0659:PROSDI>2.0.CO;2

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Abstract

Tufa (spring) deposits in the Tecopa basin, California, reflect the response of arid groundwater regimes to wet climate episodes. Two types of tufa are represented, informally defined as (1) an easily disaggregated, fine-grained mixture of calcite and quartz (friable tufa) in the southwest Tecopa Valley, and (2) hard, vuggy micrite, laminated carbonate, and carbonate-cemented sands and gravels (indurated tufa) along the eastern margin of Lake Tecopa. High δ18OVSMOW (Vienna standard mean ocean water) water values, field relations, and the texture of friable tufa suggest rapid nucleation of calcite as subaqueous, fault- controlled groundwater discharge mixed with high-pH, hypersaline lake water. Variations between δ18OVSMOW and δ13CPDB (Peedee belemnite) values relative to other closed basin lakes such as the Great Salt Lake and Lake Lahontan suggest similarities in climatic and hydrologic settings. Indurated tufa, also fault controlled, formed mounds and associated feeder systems as well as stratabound carbonate-cemented ledges. Both deposits represent discharge of deeply circulated, high total dissolved solids, and high pCO2 regional groundwater with kinetic enrichments of as much as several per mil for δ18OVSMOW values. Field relations show that indurated tufa represents episodic discharge, and U-series ages imply that discharge was correlated with cold, wet climate episodes. In response to both the breaching of the Tecopa basin and a modern arid climate, most discharge has changed from fault-controlled locations near basin margins to topographic lows of the Amargosa River drainage at elevations 30–130 m lower. Because of episodic climate change, spring flows may have relocated from basin margin to basin center multiple times.

Geospatial Extents

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Paleohydrologic record of spring deposits in and around Pleistocene pluvial Lake Tecopa, southeastern California
Series title:
GSA Bulletin
DOI:
10.1130/0016-7606(2001)113<0659:PROSDI>2.0.CO;2
Volume
113
Issue:
5
Year Published:
2001
Language:
English
Publisher:
Geological Society of America
Contributing office(s):
Denver Federal Center
Description:
12 p.
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
GSA Bulletin
First page:
659
Last page:
670
Number of Pages:
12
Country:
United States
State:
California
City:
Tecopa
Other Geospatial:
Lake Tecopa