Abstract Petrographic, mineralogical and geochemical analyses of mixed siliciclastic-carbonate offshore deposits of the Pilmatue Member (Neuquen Basin) were carried out to define two scenarios for deposition: a confined ramp setting (CRS) and an open ramp setting (ORS). The CRS involves marly to carbonate-rich fine-grained mudstones, mostly laminated and non-bioturbated, enriched in redox proxies and depleted in rare earth elements (REE). The ORS comprises abundant siliciclastic-rich mudstones, mostly coarser-mudstones, depleted in redox proxies and with REE pattern similar to the PAAS. These variations are explained through fluctuations in carbonate productivity/terrigenous input, and changes in the circulation pattern of the basin. Within the CRS, high carbonate productivity would be favored due to the general greenhouse condition for the Early Cretaceous and the scarcity of terrigenous supply, related to the landward migration of the shoreline and low effectiveness of sediment distribution by marine currents. Furthermore, high organic matter productivity should lead to an oxygen-depletion close to the sediment-water interface. Instead, increasing sediment supply and dissolved oxygen in the ORS is related to shoreline progradation in the south and the consequent installation of across shelf flows that allowed vertical water circulation and the oxygen replenishment in benthic environment.

中文翻译：

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内乌肯盆地（阿根廷）皮尔马图段（上瓦兰吉阶-下豪特里阶）细粒岩石的岩石学、矿物学和地球化学特征：对硅质碎屑输入、碳酸盐生产力和氧化还原条件的影响

摘要 对皮尔马图段（内乌肯盆地）的混合硅质碎屑-碳酸盐离岸矿床进行了岩石学、矿物学和地球化学分析，以确定两种沉积场景：封闭斜坡环境 (CRS) 和开放斜坡环境 (ORS)。CRS 涉及马里岩到富含碳酸盐的细粒泥岩，主要是层状和非生物扰动的，富含氧化还原代理物并贫乏稀土元素 (REE)。ORS 包含丰富的富含硅质碎屑的泥岩，主要是较粗的泥岩，缺乏氧化还原代理，具有类似于 PAAS 的 REE 模式。这些变化可以通过碳酸盐生产力/陆源输入的波动以及盆地环流模式的变化来解释。在 CRS 内，由于早白垩世的一般温室条件和陆源供应稀缺，与海岸线向陆迁移和海流沉积物分布效率低有关，高碳酸盐生产力将受到青睐。此外，高有机物生产力会导致靠近沉积物-水界面的氧气消耗。相反，ORS 中沉积物供应和溶解氧的增加与南部的海岸线进积以及随之而来的跨大陆架流的安装有关，这些流允许垂直水循环和底栖环境中的氧气补充。高有机物生产力应该导致靠近沉积物-水界面的氧气消耗。相反，ORS 中沉积物供应和溶解氧的增加与南部的海岸线进积以及随之而来的跨大陆架流的安装有关，这些流允许垂直水循环和底栖环境中的氧气补充。高有机物生产力应该导致靠近沉积物-水界面的氧气消耗。相反，ORS 中沉积物供应和溶解氧的增加与南部的海岸线进积以及随之而来的跨大陆架流的安装有关，这些流允许垂直水循环和底栖环境中的氧气补充。