海相油气地质2018，Vol.23Issue(1)：29-36,8.DOI:10.3969/j.issn.1672-9854.2018.01.004
桑托斯盆地白垩系盐下Barra Velha组叠层石灰岩沉积环境探讨
Depositional Environment of Stromatolitic Limestone of Pre-salt Barra Velha Formation in Santos Basin,Brazil
摘要
Abstract
By using lithological and geochemical methods, the depositional environment of stromatolitic limestone of pre-salt Barra Velha Formation in Santos Basin, offshore Brazil, was analyzed. It is concluded that the dominating fabric of stromatolitic limestone consist of shrub, finger-like and spherulitic stromatolites, which relate to depositional environment evolutionarily. From a macroscopic view, many stromatolites occur in aggregation with overlaid and adjacent pattern. The main consitution of stromatolite are made of sparry calcite precipitated directly from lake water and microbial-mediated micrite. The stromatolites, although not produced by microorganism directly, are influenced significantly by microorganism.That the high contents of magnesium and silicon, and the positive depletion in carbon and oxygen isotopes, which have been measured from stromatolitic samples, indicate a saline environment with intensive evaporation, mirroring a closed lacustrine system. Stromatolite aggregates with several centimeters in height are widespread, which implies the depth of water favored stromatolite growth did not last long, perhaps on a millennium scale or even shorter, and that stromatolites grown with different and alternate height vertically shows that the frequent fluctuation in water depth was common during that period.关键词
桑托斯盆地/白垩系/BarraVelha组/叠层石灰岩/微生物/沉积环境Key words
Stromatolite/Depositional environment/Microorganism/Barra Velha Formation/Cretaceous/Santos Basin分类
能源科技引用本文复制引用
康洪全,吕杰,程涛..桑托斯盆地白垩系盐下Barra Velha组叠层石灰岩沉积环境探讨[J].海相油气地质,2018,23(1):29-36,8.基金项目
本文受国家科技重大专项"西非—南美海域重点区油气地质评价及关键技术研究"(编号:2017ZX05032-001)资助 （编号:2017ZX05032-001）
