定量再造湖泊古生产力的尝试

根据海洋学计算古生产力的方法，利用云南现代陆相断陷湖盆的沉积学和生物学资料，推导出了湖泊中用有机碳法计算古生产力的公式：R＝C×ρ×（1－Φ）／（0．00421×S^0.0826），并比较了用此公式和海洋中计算古生产力的公式计算出的山东济阳坳陷沙三段沉积时期的古生产力。结果表明，湖泊古生产力大多高于海洋古生产力，推导出来的计算湖泊古生产力大多的公式，对定量计算新生代古湖泊，尤其是类似于渤海湾盆地的断陷湖泊的古生产力有着重要的实际意义。

An Attempt on Quantitative Calculation of Lake Palaeoproductivity

palaeoproductivitity is defined as the rate of energy absorbed by organism during the course of circulation of energy，that is，the quantity of organic matter per unit time and per unit area．The method of calculating palasoproductlvity in the ocean was studied by Müiller and Suess(1979)and the formula：R=C x×ρs×(1-φ)／(0．0030×s0.30)was obtained．This formulais deduced on the basis of surface sediments from Pacific Ocean，Atlantic Ocean, and Baltic Sea regions， and the majority of its sedimentary organic matter is of marine origin. Therefore，this for mula can only be used for sea regions where the nonmarine organic matters are basically absent．In our country most Mesozoic and Cenozoic basins containing oi1 and gas are nonmarine lakas．The organism transported to the lakes from the land occupies a large proportion．It has obvious difference from the organism deposited in ocean. Consequently，the relation(formula)between palaeoproductivity and organic carbon in the nonmarine 1akes should be rededuced．Based on the method of calculating palaeoproductivity in the ocean and using related sedimentologica l and biological data of modern nonmarine downfaulted basins in Yunnan Province，we obtained a formula for calculating palaeoproductivity using the method of organic carbon in the lake：R =C × ρs×(1-φ )／(0.00421 × S0.0826) Furthermore，we compared the palaeoproductivity values calculated by this formula with those calculated by the ocean formula for the Third Member of the Shahejie Formation of the Jiyang Depression．Shadong Province The results show that the productivity of the lakes is much higher than that of the ocean．This new formula is of significance in quantitative calculation of pa1aeoproductivity for the Cenozoic lakes，such as the Bohai Bay Basin which is a dovnafaulted basin．