Abstract The Monte Alegre Formation corresponds to the main reservoir rock in the Amazonas Basin petroleum system in Brazil and is correlated with the Pennsylvanian rocks of the Parnaiba and Solimoes basins. Previous outcrop and well-based studies are concentrated on the southern edge of the basin and show that the Monte Alegre Formation basically represents an aeolian, deltaic and transitional marine succession. However, there is no published research that demonstrates the depositional system in the northern edge of Amazonas Basin. In this sense, outcrop-based facies and stratigraphic analysis is carried-out to understand the distal influence of marine incursion into the basin and its relationship with paleogeography in the Upper Carboniferous. The data show that the aeolian Monte Alegre system is represented by a braided fluvial system formed by five architectural elements: (i) sandy bedform, (ii) downstream-accretion macroform, (iii) gravel bars and bedforms, (iv) channel and (v) laminated sand sheets, pointing to a braided depositional system. The aeolian succession overlies the fluvial system and is represented by medium-scale trough cross-bedding and large-scale planar cross-bedded sandstones resulting from the accumulation and migration of transverse dunes toward the northwest that grade upward to dry interdunes and aeolian sand sheet deposits that are interbedded, consisting basically of translatent ripple cross-lamination and low-angle cross-stratified lamination sandstones related to water table raises. The stratigraphic record defines a wetting-upward stacking pattern of Monte Alegre Formation resulting from local sea level rise as a result the advance of the marine incursion that settled in the central-western region of Gondwana during the Late Carboniferous. Thus, in addition to corroborating the paleo wind directions predicted for the region during the Late Carboniferous, these deposits help to understand the paleoenvironmental relations between the northern and southern edges of the Amazonas Basin.

中文翻译：

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早期宾夕法尼亚河流 - 亚马逊盆地（冈瓦纳中西部）的风成相互作用及其与海侵的关系

摘要 Monte Alegre 组对应于巴西亚马逊盆地石油系统中的主要储集岩，并与 Parnaiba 和 Solimoes 盆地的宾夕法尼亚岩石相关。以前的露头和基于井的研究集中在盆地的南部边缘，表明 Monte Alegre 组基本上代表了风成、三角洲和过渡海洋序列。然而，没有已发表的研究证明亚马逊盆地北部边缘的沉积系统。从这个意义上说，开展露头相和地层分析，以了解海相侵入盆地的远侧影响及其与上石炭统古地理的关系。数据显示，风成 Monte Alegre 系统由五个建筑元素形成的辫状河流系统表示：(i) 砂质基床，(ii) 下游沉积宏观构造，(iii) 砾石坝和基床，(iv) 河道和 ( v) 层压砂板，指向编织沉积系统。风积层序覆盖在河流系统之上，以横向沙丘向西北堆积和运移形成的中尺度槽交错层理和大尺度平面交错层理砂岩为代表，向上分级为干燥的沙丘间和风积砂层沉积互层，主要由与地下水位升高有关的平移波纹交叉层理和低角度交叉层理砂岩组成。地层记录定义了Monte Alegre组的湿润向上堆积模式，这是由于晚石炭世期间在冈瓦纳中西部地区定居的海洋入侵的推进导致当地海平面上升。因此，除了证实晚石炭世对该地区预测的古风向之外，这些沉积物还有助于了解亚马逊盆地北部和南部边缘之间的古环境关系。