柴达木盆地盐湖有孔虫的发现及其地质意义

DISCOVERY OF FORAMINIFERA IN THE SALT LAKE,CHAIDAMU BASIN AND ITS GEOLOGICAL SIGNIFICANCE

青海省柴达木盆地小柴旦盐湖第四纪晚期沉积内发现海相世系的有孔虫化石希望虫Elphidium sp.,而且与典型盐湖介形类肥胖真星介Eucypris inflata共生,这是罕见的发现。该湖海拔3172m,距最近的海1700km,迄今为止,是地球上发现有孔虫距海遥远且海拔最高的盐湖。根据柴达木盆地地理和沉积、生物演化史分析,难以用海侵或残留海观点解说该有孔虫的来源。这一发现说明内陆盐湖存在少量海相世系生物是个事实。论文讨论了空中通道是一个可能的生物传布途径。将今论古,如果在含盐岩系中出现少量广盐性有孔虫或其他海相世系生物化石,需要作具体分析,不一定全都是海侵或残留海的证据。

Marine foraminifera fossils Elphidium sp. have been found and are associated with typi-cal salt lake ostracoda-Eucypris inrlata fossils in late Quaternay in Xiao Chaidan salt lake in Chaidamu Basin, Qinghai Province, This is a very seldom phenomenon. This lake, with an al-titude of 3172m, is located at a distance of 1700km from the nearest ocean. It is a highest and most distant salt lake from ocean in the earth in which foraminifera fossils have been found,until now. Based on an analysis of the geography and sedimentation as well as an evolution of organisms, the source of marine foraminifera can hardly be explained either through a point of view of sea transgression or a remnant sea. This discovery demonstrates a fact that there are small amount of marine organisms in an inland salt lake. This paper suggests that air pathway is a possible route for organism transmission. It is postulated from present events that small amount of euryhaline foraminifera or other marine organisms in saline formations connbe analyzed further in detail.