Abstract The Acre Basin has a complex geology that is related to the Andean uplift and it still is one of the least understood Brazilian sedimentary basins due in part to difficulties in accessing outcrops. Its geological history is related to several subandean basins including Maranon, Ucayali and Madre de Dios in Peru, and the Solimoes Basin in Brazil. These basins have potential for oil and gas which raised interest in the Brazilian oil industry since 1930. During this period, 11 wells were drilled in Acre, one of which is herein studied (2CDST001-AC). Available information from this 2600 m-thick borehole suggested an age spanning from the Albian to the Pliocene. We performed palynological analyses in 29 core-samples spread along the well. Our new data indicated much younger ages, spanning from Eocene to late Miocene together with a middle to late Miocene marine incursion. The palynological assemblage of the Solimoes Formation in the Acre basin is similar to that of the adjacent Solimoes Basin, but with a much thicker stratigraphic sequence offering a greater potential to unravel the history of western Amazonia during the Cenozoic.

中文翻译：

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巴西 Acre 盆地 Ramon 和 Solimões 组的孢粉层地层学

摘要 Acre 盆地具有与安第斯隆起相关的复杂地质，但由于难以接近露头，它仍然是巴西最不为人知的沉积盆地之一。其地质历史与几个亚安德盆地有关，包括秘鲁的马拉农、乌卡亚利和马德雷德迪奥斯，以及巴西的索利莫斯盆地。自 1930 年以来，这些盆地具有石油和天然气的潜力，引起了巴西石油工业的兴趣。在此期间，在 Acre 钻了 11 口井，本文研究了其中一口井 (2CDST001-AC)。来自这个 2600 米厚钻孔的可用信息表明，它的年龄跨度从阿尔布世到上新世。我们对沿井分布的 29 个岩心样品进行了孢粉学分析。我们的新数据表明年龄要小得多，从始新世到晚中新世以及中新世中晚期海洋入侵。Acre 盆地 Solimoes 组的孢粉组合与相邻的 Solimoes 盆地相似，但地层层序更厚，为揭示新生代亚马逊西部的历史提供了更大的潜力。