Late quaternary climate and hydrology of tropical South America inferred from an isotopic and chemical model of Lake Titicaca, Bolivia and Peru

被引:67
作者
Cross, SL
Baker, PA
Seltzer, GO
Fritz, SC
Dunbar, RB
机构
[1] Duke Univ, Div Earth & Ocean Sci, Durham, NC 27708 USA
[2] Syracuse Univ, Dept Geol, Syracuse, NY 13244 USA
[3] Univ Nebraska, Dept Geosci, Lincoln, NE 68588 USA
[4] Stanford Univ, Dept Geol & Environm Sci, Stanford, CA 94305 USA
基金
美国国家科学基金会;
关键词
Lake Titicaca; Altiplano; lake level; paleohydrology; isotope chemistry;
D O I
10.1006/qres.2001.2244
中图分类号
P9 [自然地理学];
学科分类号
0705 ; 070501 ;
摘要
A simple mass balance model provides insight into the hydrologic, isotopic, and chemical responses of Lake Titicaca to past climatic changes. Latest Pleistocene climate of the Altiplano is assumed to have been 20% wetter and 5 degreesC colder than today, based on previous modeling. Our simulation of lacustrine change since 15,000 cal yr B.P. is forced by these modeled climate changes. The latest Pleistocene Lake Titicaca was deep, fresh, and overflowing. The latest Pleistocene riverine discharge from the lake was about 8 times greater than the modern average, sufficient to allow the expansion of the great paleolake Tauca on the central Altiplano. The lake delta O-18 value averaged about -13 parts per thousand SMOW (the modern value is about -4.2 parts per thousand). The early Holocene decrease in precipitation caused Lake Titicaca to fall below its outlet and contributed to a rapid desiccation of paleolake Tauca. Continued evaporation caused the 100-m drop in lake level, but only a slight(1-2 parts per thousand) increase (relative to modern) in delta O-18 Of early Holocene lake waters. This Holocene lowstand level of nearly 100 m was most likely produced by a precipitation decrease, relative to modern, of about 40%, The lake was saline as recently as 2000 cal yr B.P. The timing of these hydrologic changes is in general agreement with calculated changes of insolation forcing of the South American summer monsoon, (C) 2001 University of Washington.
引用
收藏
页码:1 / 9
页数:9
相关论文
共 49 条
[1]   A 3500 C-14 yr high-resolution record of water-level changes in Lake Titicaca, Bolivia/Peru [J].
Abbott, MB ;
Binford, MW ;
Brenner, M ;
Kelts, KR .
QUATERNARY RESEARCH, 1997, 47 (02) :169-180
[2]  
[Anonymous], CLIMATES CENTRAL S A
[3]  
[Anonymous], LAKE TITICACA
[4]  
[Anonymous], 1976, CLIMATE BRAZIL CLIMA
[5]   The history of South American tropical precipitation for the past 25,000 years [J].
Baker, PA ;
Seltzer, GO ;
Fritz, SC ;
Dunbar, RB ;
Grove, MJ ;
Tapia, PM ;
Cross, SL ;
Rowe, HD ;
Broda, JP .
SCIENCE, 2001, 291 (5504) :640-643
[6]  
BAKER PA, 1999, EOS T AM GEOPHYS UN, V80, pF531
[7]   Climate and lake-level history of the northern Altiplano Bolivia, as recorded in Holocene sediments of the Rio Desaguadero [J].
Baucom, PC ;
Rigsby, CA .
JOURNAL OF SEDIMENTARY RESEARCH, 1999, 69 (03) :597-611
[8]   HYDRO-ISOSTATIC DEFLECTION AND TECTONIC TILTING IN THE CENTRAL ANDES - INITIAL RESULTS OF A GPS SURVEY OF LAKE MINCHIN SHORELINES [J].
BILLS, BG ;
DESILVA, SL ;
CURREY, DR ;
EMENGER, RS ;
LILLQUIST, KD ;
DONNELLAN, A ;
WORDEN, B .
GEOPHYSICAL RESEARCH LETTERS, 1994, 21 (04) :293-296
[9]   Climate variation and the rise and fall of an Andean civilization [J].
Binford, MW ;
Kolata, AL ;
Brenner, M ;
Janusek, JW ;
Seddon, MT ;
Abbott, M ;
Curtis, JH .
QUATERNARY RESEARCH, 1997, 47 (02) :235-248
[10]  
Blodgett T.A., 1997, EARTH INTERACTIONS, V1