The stratigraphic architecture of Early Jurassic strata exposed along a >10 km long transect in the Chachil Graben, an exhumed marine rift depocentre in the Neuquén Basin (Argentina), provides insights into the sedimentological and stratigraphic expression of the syn-rift to post-rift transition. A change from syn-rift intrabasinal carbonate to post-rift extrabasinal siliciclastic sedimentation is recorded, as well as variations in sediment supply and dispersal patterns across rift-related topography. The late syn-rift was marked by a transgression and development of a shallow-marine carbonate system, including carbonate platform deposits perched on fault-block highs and periplatform deposits accumulated in fault-block lows, which overlies continental volcano-sedimentary syn-rift deposits. Differential subsidence and basin deepening induced retrogradation of the carbonate system, which was progressively drowned and overlain by organic-rich calcareous mudstone that draped across rift structures at the onset of the early post-rift. The first extrabasinal siliciclastic influx led to progradation of an early post-rift intraslope lobe complex into the graben, which is associated with kilometre-scale clastic injectites. The depositional architecture, facies distribution and pinch-out style of intraslope lobes record the effects of an inherited compaction hinge, which acted as an oblique counterslope to sediment gravity flows. The occurrence of combined-flow bedforms, widespread erosion, and limited facies segregation across lobes bearing different hybrid event bed types, is in sharp contrast to sedimentological characteristics of existing intraslope lobe models. Documentation of the syn-rift to post-rift transition stratigraphy permitted identification of changes in thickness and facies resulting from the passive infill of inherited topography with early post-rift differential compaction. This architecture contrasts markedly with those developed during syn-rift normal faulting. Furthermore, the influence of local inherited topography on the development of early post-rift lobes is key to improve subsurface prediction of sandstone distribution and quality during assessment of hydrocarbon reservoirs and carbon storage sites.

中文翻译：

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从同裂谷碳酸盐岩到裂谷后早期深海陆坡内裂片的演化：裂谷盆地地貌对沉积模式的作用

沿着内乌肯盆地（阿根廷）挖掘出的海相裂谷沉积中心 Chachil Graben 中超过 10 公里长的断面出露的早侏罗世地层的地层结构提供了对同裂谷到裂谷后的沉积学和地层表达的见解过渡。记录了从同裂谷盆地内碳酸盐岩到裂谷后盆地外硅质碎屑沉积的变化，以及跨裂谷相关地形的沉积物供应和扩散模式的变化。晚同裂谷以浅海碳酸盐岩系统的海侵和发育为标志，包括位于断块高处的碳酸盐台地沉积物和堆积在断块低处的台地周围沉积物，其覆盖在大陆火山沉积同裂谷沉积物之上. 差异下沉和盆地加深导致碳酸盐岩系统回生，在裂谷后早期开始时，碳酸盐岩系统逐渐被富含有机质的钙质泥岩淹没和覆盖，这些泥岩覆盖在裂谷构造上。第一次盆地外硅质碎屑流入导致早期裂谷后斜坡内裂片复合体进入地堑，这与千米级碎屑注入体有关。斜坡内裂片的沉积结构、相分布和尖灭样式记录了继承压实铰链的影响，它作为沉积物重力流的斜反坡。混合流床型的出现、广泛的侵蚀和不同混合事件床类型的裂片之间的有限相分离，与现有斜坡内叶模型的沉积学特征形成鲜明对比。对同裂谷到裂谷后过渡地层的记录允许识别由裂谷后早期差异压实的继承地形的被动填充引起的厚度和相的变化。这种架构与在同步裂缝正常断层期间开发的架构形成鲜明对比。此外，局部继承地形对早期裂谷后裂片发育的影响是提高油气藏和碳储存地点评估过程中砂岩分布和质量的地下预测的关键。对同裂谷到裂谷后过渡地层的记录允许识别由裂谷后早期差异压实的继承地形的被动填充引起的厚度和相的变化。这种架构与在同步裂缝正常断层期间开发的架构形成鲜明对比。此外，局部继承地形对早期裂谷后裂片发育的影响是提高油气藏和碳储存地点评估过程中砂岩分布和质量的地下预测的关键。对同裂谷到裂谷后过渡地层的记录允许识别由裂谷后早期差异压实的继承地形的被动填充引起的厚度和相的变化。这种架构与在同步裂缝正常断层期间开发的架构形成鲜明对比。此外，局部继承地形对早期裂谷后裂片发育的影响是提高油气藏和碳储存地点评估过程中砂岩分布和质量的地下预测的关键。