STABLE ISOTOPE GEOCHEMISTRY OF DEEP-SEA CHERTS
STABLE ISOTOPE GEOCHEMISTRY OF DEEP-SEA CHERTS
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DOI：
10.1016/0016-7037(76)90155-1
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发表时间：
1976-01-01
影响因子：
5
通讯作者：
EPSTEIN, S
中科院分区：
文献类型：
--
作者：
KOLODNY, Y;EPSTEIN, S
DSDP在不同地点回收了74个侏罗纪至中新世的燧石样品，并分析了27个陆地暴露燧石样品的氧和氢同位素组成。这些研究伴随着矿物学分析和共存碳酸盐的一些同位素分析。燧石的δ18Oof值在27% ~ 39%之间。相对于SMOW，δ18Oof的瓷质-在30 - 42%之间。18o瓷质岩中蛋白石- ct相对于燧石中共存的微晶石英一致富集，可能是两相成岩温度（深度）不同的反映。深海燧石的δ 18oin通常随着年龄的增加而减少，这表明在过去150万年中，海底整体变冷。将这一趋势与底栖有孔虫记录的趋势进行比较（DouglasandSavin, 1975）表明，深海燧石的δ 18oin可能直到沉积后几千万年才被冻结。任何年龄的燧石δ 18o值都有分布，成岩作用的增强反映在δ 18o值的降低上。德鲁西石英的δ 18o值最低。陆地上暴露的燧石在18o年持续耗竭，与深海时间相当的燧石相比。从深海燧石中提取的水在0.5至1.4 wt %之间。该水的δD在- 78 ~ - 95%之间。并不是燧石δ 18o（或它们形成时的温度）的函数。
Seventy four samples of DSDP recovered cherts of Jurassic to Miocene age from varying locations, and 27 samples of on-land exposed cherts were analyzed for the isotopic composition of their oxygen and hydrogen. These studies were accompanied by mineralogical analyses and some isotopic analyses of the coexisting carbonates.δ18Oof chert ranges between 27 and 39%. relative to SMOW,δ18Oof porcellanite—between 30 and 42%.. The consistent enrichment of opal-CT in porcellanites in18O with respect to coexisting microcrystalline quartz in chert is probably a reflection of a different temperature (depth) of diagenesis of the two phases.δ18Oof deep sea cherts generally decrease with increasing age, indicating an overall cpoling of the ocean bottom during the last 150 m.y. A comparison of this trend with that recorded by benthonic foraminifera (DouglasandSavin, 1975) indicates the possibility ofδ18Oin deep sea cherts not being frozen in until several tens of millions of years after deposition. Cherts of any Age show a spread ofδ18Ovalues, increasing diagenesis being reflected in a lowering ofδ18O. Drusy quartz has the lowestδ18Ovalues.On-land exposed cherts are consistently depleted in18O in comparison to their deep sea time equivalent cherts.Water extracted from deep sea cherts ranges between 0.5 and 1.4 wt %. δD of this water ranges between −78 and −95%. and is not a function ofδ18Oof the cherts (or the temperature of their formation).