BACKGROUND On Late Cretaceous Tethyan upwelling sediments from the Mishash/Ghareb Formation (Negev, Israel), bulk geochemical and biomarker analyses were performed to explain the high proportion of phosphates in the lower part and of organic matter (OM) preserved in upper parts of the studied section. The profile is composed of three facies types; the underlying Phosphate Member (PM), the Oil Shale Member (OSM) and the overlying Marl Member (MM). RESULTS Total organic carbon (TOC) contents are highly variable over the whole profile reaching from 0.6% in the MM, to 24.5% in the OSM. Total iron (TFe) varies from 0.1% in the PM to 3.3% in the OSM. Total sulfur (TS) ranges between 0.1% in the MM and 3.4% in the OSM, resulting in a high C/S ratio of 6.5 in the OSM section. A mean proportion of 11.5% total phosphorus (TP) in the PM changed abruptly with the facies to a mean value of only 0.9% in the OSM and the MM. The TOC/TOCOR ratios argue for a high bacterial sulfate reduction activity and in addition, results from fatty acid analyses indicate that the activity of sulfide-oxidizing activity of bacteria was high during deposition of the PM, while decreasing during the deposition of the OSM. CONCLUSIONS The upwelling conditions effected a high primary productivity and consequently the presence of abundant OM. This, in combination with high sulfate availability in the sediments of the PM resulted in a higher sulfide production due to the activity of sulfate-reducing bacteria. Iron availability was a limiting factor during the deposition of the whole section, affecting the incorporation of S into OM. This resulted in the preservation of a substantial part of OM against microbial degradation due to naturally-occurring sulfurization processes expressed by the high C/S ratio of 6.5 in the OSM. Further, the abundant sulfide in the pore water supported the growth of sulfide-oxidizing bacteria promoting the deposition of P, which amounted to as much as 15% in the PM. These conditions changed drastically from the PM to the OSM, resulting in a significant reduction of the apatite precipitation and a high concentration of reactive S species reacting with the OM.

中文翻译：

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地球化学证据表明晚白垩世上升流系统中硫酸盐还原，硫化物氧化和磷酸盐积累之间存在联系。

背景技术在Mishash / Ghareb组（以色列内盖夫）的晚白垩纪特提斯上升流沉积物中，进行了大量地球化学和生物标志物分析以解释下部磷酸盐的高比例和上部保存的有机质（OM）的比例。研究部分。剖面由三种相类型组成。基础磷酸盐成员（PM），油页岩成员（OSM）和上覆的Marl成员（MM）。结果总有机碳（TOC）含量在整个过程中变化很大，从MM的0.6％到OSM的24.5％。总铁（TFe）从PM中的0.1％到OSM中的3.3％不等。MM中的总硫（TS）范围介于OSM中的0.1％和OSM中的3.4％之间，导致OSM部分中的C / S比率高达6.5。平均比例为11。PM中5％的总磷（TP）随相突然改变，在OSM和MM中平均值仅为0.9％。TOC / TOCOR比表明细菌硫酸盐还原活性较高，此外，脂肪酸分析结果表明，细菌的硫化物氧化活性在PM沉积期间较高，而在OSM沉积期间降低。结论上升的条件影响了较高的初生生产力，因此存在大量的OM。再加上在PM沉积物中硫酸盐的利用率高，由于减少硫酸盐的细菌的活性，导致较高的硫化物产量。铁的可用性是整个断面沉积过程中的限制因素，影响了将S掺入OM中。由于OSM中6.5的高C / S比表示自然发生的硫化过程，因此可以保留大部分的OM，以防止微生物降解。此外，孔隙水中丰富的硫化物支持了硫化物氧化细菌的生长，从而促进了P的沉积，而P的含量高达15％。这些条件从PM到OSM发生了巨大变化，从而导致磷灰石沉淀的显着减少和与OM反应的高浓度反应性S物种。占PM的15％之多。这些条件从PM到OSM发生了巨大变化，从而导致磷灰石沉淀的显着减少和与OM反应的高浓度反应性S物种。占PM的15％之多。这些条件从PM到OSM发生了巨大变化，从而导致磷灰石沉淀的显着减少和与OM反应的高浓度反应性S物种。