柴达木盆地昆特依盐湖的地球化学演化与古气候变化

１９９０年用铀系年代学及古地磁对昆特依盐湖沉积物进行年代测定，探讨该湖区地球化学演化与古气候变化关系。结果表明，该区最老的盐层形成于早更新世晚期（大于７３０ｋａ），大量的盐类沉积则始于３００ｋａ左右；盐湖沉积物中元素含量变化主要受古盐度、矿物、类质同象和吸附控制；沉积物水溶Ｆ／Ｃｌ比值与古盐度成反比关系；该湖２０００ｋａ以来的古环境演变：盐层形成于干冷、偏酸性的氧化环境，泥岩层形成于湿暖、偏碱性的

STUDY OF GEOCHEMICAL EVOLUTION AND PALAEOCLIMATIC F LUCTUATION OF KUNTEYI SALT LAKE IN THE QAIDAM BASIN, QINGHAI

In 1990 uranium series age, paleomagnetic and geochemical study of the sedi-ment from Kunteyi Salt Lake in the Qaidam Basin were carried out to approachthe relation between geochemical evolution and paleoclimatic evolution of the lake.The results show that the earliest salt layer was formed in the late of Lower Pleis-tocene (730 thousands years ago). Large scale halite precipitation began about 300thousand years ago.The elemental content variations are controlled by salinity, mi-neral-forming, isomophic replacement and adsorption. Water soluable F/Cl ratio isan new indicator of palaeosalinity, the former is inversely proportional to the lat-ter. Salt layers in the Kunteyi Salt Lake were formed in oxidation-subacid underdry-cold palaeoclimate, mud layers in reduction-subalkalinity under warm-moist pala-eoclimate. On the basis of element geochemistry, palaeosalinity and sedimentology,authors suggest there have been 8 large palaeoclimate fluctuations (from the warm-moist to cold-dry) during the last 730 ka in the region of Kunteyi Salt Lake.