Abstract The low-latitude Marinoan glaciation (635 Ma) record in the southern Amazon Craton has been one of the most important sites with strong evidence for the Neoproterozoic Snowball Earth hypothesis. In Central Brazil, the 50-m-thick carbonate succession of the post-Marinoan cap carbonate exposed in the Tangara da Serra region, Central Brazil, represents a complementary section of the classical occurrence of the Puga cap carbonate in Mirassol d'Oeste region, that overlies glaciogenic deposits marking the well-preserved Cryogenian-Ediacaran boundary in South America. The 8-m-thick cap dolostone that represents the Mirassol d'Oeste Formation consists of pinkish microcrystalline peloidal dolomudstone, exhibiting even parallel to low-angle lamination locally tubestone, and megaripple bedded dolopackstone. The cap dolostone is succeeded upsection by the cap cementstone limestone (basal Guia Formation), comprising laminated lime mudstone rich in silt-sized terrigenous grains (quartz), and subordinately bituminous shale, dolomitic marls, intraformational breccias, and abundant calcite crystal fans and crusts. Crystal fans occur in isolated and decimetre-scale arrays and are considered aragonite pseudomorphs. Primary precipitation of dolomite, crystal fans, and micrite and the formation of tubestone are related to depositional processes. The cap dolostone was affected by the neomorphism of the dolomicrite, development of vug and intercrystalline porosity, euhedral dolomite precipitation, synsedimentary fracturing, calcite and quartz precipitation, chemical compaction, Fe-oxide substitution, and precipitation. The diagenetic processes of the cap cementstone limestone were pyrite precipitation, calcite cementation, neomorphism of micrite and crystal fan, partial crystal fan dissolution, dolomitization, chemical compaction, fracturing, ferrous dolomite and calcite precipitation, pyrite (pseudomorph) and micrite replacement with Fe-oxide and replacement of rhombohedral dolomite by Mn-oxides. Hydrocarbons are rare and its migration represents the last diagenetic event being found: 1) in fractures and interpeloidal, vug and intercrystalline pores (~2%) with low permeability and connectivity of the cap dolostone; and 2) in intercrystalline pores, fractures, and rare pores in crystal fans of the cap cementstone limestone. During the post-Marinoan sea-level rise occurred the establishment of a shallow to moderately deep microbially induced dolomitic platform locally influenced by storm-action. The progressive transgression led the implantation of a deep anoxic and CaCO3-oversaturated aragonitic platform. The similarities of cap carbonate microfacies among the post-Marinoan succession worldwide reflects an extraordinary and non-recurring global precipitation event in geological history. In contrast, besides the majority of cap carbonate have the same textural and compositional framework, the diagenetic history seems to be regional and completely dependent on the tectonic, thermal, and burial history of the depositional basins where they were deposited.

中文翻译：

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亚马逊克拉通南部新元古代盖层碳酸盐微相、成岩作用及油气潜力

摘要 亚马逊克拉通南部低纬度马里诺安冰期（635 Ma）记录是新元古代雪球地球假说的有力证据的最重要地点之一。在巴西中部，在巴西中部 Tangara da Serra 地区出露的后 Marinoan 盖层碳酸盐的 50 米厚的碳酸盐序列代表了 Mirassol d'Oeste 地区 Puga 盖层碳酸盐经典产状的补充部分，它覆盖在标志着南美洲保存完好的低温纪-埃迪卡拉纪边界的冰川沉积物之上。代表 Mirassol d'Oeste 组的 8 米厚盖顶白云岩由粉红色微晶球状白云岩组成，甚至呈现出平行于低角度层理的局部管状岩和巨波纹层状白云岩。盖层白云岩由盖层灰岩（基底东望洋组）向上断续，由富含粉砂大小陆源颗粒（石英）的层状灰泥岩和次要的沥青质页岩、白云质泥灰岩、地内角砾岩和丰富的方解石晶扇和结壳组成. 水晶扇出现在孤立的分米级阵列中，被认为是文石假晶。白云岩、晶扇、泥晶的原生沉淀和管状岩的形成与沉积过程有关。盖层白云岩受白云岩新晶作用、孔洞和晶间孔隙发育、自形白云岩沉淀、同沉积压裂、方解石和石英沉淀、化学压实、Fe-氧化物取代和沉淀的影响。盖层胶结岩灰岩的成岩过程为黄铁矿沉淀、方解石胶结、泥晶和晶扇的新形作用、部分晶扇溶解、白云石化、化学压实、压裂、亚铁白云石和方解石沉淀、黄铁矿（假晶质）和泥晶与Fe-锰氧化物和菱面体白云石的替代。烃类是稀有的，它的迁移代表了被发现的最后一次成岩事件：1）在裂缝和盘间、孔洞和晶间孔隙（~2%）中，具有低渗透性和盖层白云岩的连通性；2) 盖层胶结岩灰岩晶间孔、裂缝和晶扇中的稀有孔。在后马里诺斯海平面上升期间，在局部受风暴作用影响的浅到中等深度微生物诱导的白云岩平台的建立。渐进的海侵导致了深度缺氧和 CaCO3 过饱和的文石平台的植入。世界范围内后马里诺斯演替中盖碳酸盐微相的相似性反映了地质历史上一次非同寻常的全球降水事件。相比之下，除了大多数盖层碳酸盐具有相同的构造和组成框架外，成岩历史似乎是区域性的，完全取决于它们沉积的沉积盆地的构造、热和埋藏历史。渐进的海侵导致了深度缺氧和 CaCO3 过饱和的文石平台的植入。世界范围内后马里诺斯演替中盖碳酸盐微相的相似性反映了地质历史上一次非同寻常的全球降水事件。相比之下，除了大多数盖层碳酸盐具有相同的构造和组成框架外，成岩历史似乎是区域性的，完全取决于它们沉积的沉积盆地的构造、热和埋藏历史。渐进的海侵导致了深度缺氧和 CaCO3 过饱和的文石平台的植入。世界范围内后马里诺斯演替中盖碳酸盐微相的相似性反映了地质历史上一次非同寻常的全球降水事件。相比之下，除了大多数盖层碳酸盐具有相同的构造和组成框架外，成岩历史似乎是区域性的，完全取决于它们沉积的沉积盆地的构造、热和埋藏历史。