Late Quaternary paleoenvironments of ancient Lake Mojave--reconstructing the history from stratigrap

来源 :“东亚欧环境变化过程-亚洲季风变化与高低纬气候相互作用”第八届国际研讨会 | 被引量 : 0次 | 上传用户:nfx0123
下载到本地 , 更方便阅读
声明 : 本文档内容版权归属内容提供方 , 如果您对本文有版权争议 , 可与客服联系进行内容授权或下架
论文部分内容阅读
  Late Quaternary fluctuations of pluvial Lake Mojave are recorded in subsurface, cored lake deposits and shoreline features in the terminal depositional basins (Silver Lake and Soda Lake) of the Mojave River.Lake Mojave was one of two large late Quaternary lakes sustained by the Mojave River with the other being the upstream Lake Manix.Silver Lake Depositional Basin (SiLDB) contains a high resolution stratigraphic sequence due to its shallowness and minimal relief across the pre-lake basin floor.Lake building in SiLDB began at ~22 ka with two major high and persistent lake stands occurring between ~18.4 ka and ~16.6 ka (LMⅠ) and ~13.7 ka and ~11.4 ka (LMⅡ).Overflow from Lake Manix sustained LMⅠ which stabilized at the A-shoreline (elevation 287~288 m).LMⅡ coincided with breaching and draining of Lake Manix, reducing the storage capacity of Lake Mojave, increasing its evaporative surface area, and enhancing overflow from Lake Mojave into Death Valley.This overflow downcut the Lake Mojave oudet spillway between 12 ka and 11 ka, ultimately stabilizing at an elevation of 285.5 m (B-shoreline).The majority of shoreline features currendy found around the margins of Silver Lake and Soda Lake date to LMⅡ/B-shoreline, as the shallow lake conditions resulted in erosion of older LMⅠ landforms.SiLDB also experienced alternating periods of intermittent lake conditions and periods of desiccation some during higher stands and more continuous Lake Mojave phases with a significant drying event occurring ~15.5 ka.Total drying of Lake Mojave occurred by ~8.7 ka, with playa conditions dominating the Holocene.Using the history of lake level elevations and a simplified, precipitationdischarge/evaporation model, we infer that the late Pleistocene hydrologic conditions resulting in Lake Mojave overflow at Spillway bay in Silver Lake lie between two sets of conditions: (1) a 50% increase in precipitation in the headwater catchment resulting in annual flood events reaching SiLDB with discharges three times that of the modern extreme flood; or (2) a 100% increase in catchment precipitation with a 50% decrease from modern evaporation combined with annual flood events reaching Afton Canyon with discharges two times that of the modern extreme floods.
其他文献
Lake Dood is a fresh water lake, remnant of a large glacial lake in the Darkhad basin.Northern Mongolia is located at the coordinate of 51°20′ N, 99°23′E, in 1538 m a.s.l..The length of the lake is 7.
会议
The tributary rivers Amu Darya and Syr Darya contribute major amounts of water to the hydrological budget of the endorheic Aral Sea.Processes controlling the flow of water into rivers in the headwater
会议
The paper presents new results in geochemistry and diatoms analyses of the short sediment cores, obtained in 2005 from the Lake Dood (Darhad Basin).The names, length and locations of cores are as foll
会议
Recent drilling in Lake Hovsgol, NW Mongolia, recovered a sedimentary sequence with a base age of 1 cal Ma from the second-largest lake in the Baikal Rift Zone.Because of the small catchment, Hovsgol
会议
Lake Hovsgol at 51°N in NW Mongolia is located in a rift basin with a small confined catchment.This lake serves as a sensitive "water gauge" in a region dominated by westerly atmospheric circulation i
会议
Xingkai Lake is situated at mid-high latitudes, where the climate is dry and cold in winter due to the regime of the Mongolia High; in summer, however, the climate is rainy and hot owing to the heat-a
会议
Lake Hovsgol is located in high-altitudinal (1660 m) northern Mongolia which is a southern part of the Baikal Rift Zone formed about 2.5~4 Ma.We collected 20 gravity cores in 2004 to 2006 and 4 box co
会议
The Asian monsoon evolution has been significantly influenced by the orbital forcings, especially by the insolation variations induced by precession.From 1980s, many observations and simulations, part
会议
We developed a composite oxygen isotopic record of cave calcite for the last 1860 a based on three stalagmites from the Huangye Cave in eastern Gansu Province, northern China.The 18O values reflect mo
会议
Abrupt climate changes such as Dansgaard-Oeschger (D-O) cycles and Heinrich events (HEs) are prevalent during the last glacial cycle and widely documented in Northern Hemisphere (NH) high latitudes.Ho