The Early Miocene Pirabas Formation represents extensive carbonate and siliciclastic belts deposited in marine coastal environments along the eastern Amazon coast. This formation was studied in its palynological, crustacean decapods and sedimentary facies, to develop a model of its depositional processes, faunal and floral assemblages and the sedimentary environments, as observed in the B17 mine (Capanema, Pará). The sedimentary records consist mostly of light gray to greenish gray mudstones with tidal bedding, calciferous sandstones, stratified biocalcirudites and levels with conglomerates deposited in a carbonate/siliciclastic transitional system with lagoon, tidal flat, flood-tide delta and foreshore environments. 18 palynomorph species were identified in the tidal flat deposits including one alga, five pteridophytes and nine angiosperms. Among the latter, mangrove pollen and spores of Zonocostites ramonae, Zonocostites minor and Deltoidospora adriennis are reported. Nine species of crustacean decapods were recognized in the foreshore deposits, comprising one Callianassoidae, two Calappidae and six Portunidae, represented by Euphylax, †Necronectes, Portunus and Scylla, the ecology of which is associated with beaches of marginal lagoons. The main factor in the formation of these carbonate environments is assumed to have been related to the lack of a large-scale drainage system such as the Amazon River basin in the transition Oligocene–Miocene, which may also have influenced carbonate production and resulted in a strong decrease of paleodischarges from incipient river systems along the Amazon coast.

中文翻译：

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勘误至：新近纪东部亚马逊碳酸盐岩台地和古环境解释

中新世早期的Pirabas组代表了沉积在亚马逊东部沿海海洋环境中的广泛的碳酸盐和硅质碎屑带。如在B17矿山（卡帕内玛，帕拉）中所观察到的那样，已对其孢粉学，甲壳纲十足动物和沉积相进行了研究，以建立其沉积过程，动物和花卉组合以及沉积环境的模型。沉积记录主要包括浅灰色至绿色的潮汐层状泥岩，钙化砂岩，层状生物钙钙石和含砾岩的碳酸盐/硅酸盐过渡系统沉积物，具有泻湖，潮滩，潮汐三角洲和前滨环境。在潮滩沉积物中鉴定出18种单孢子虫种类，其中包括1个藻类，5个蕨类植物和9个被子植物。在后者中，据报道有褐红的花粉和Zonocostites ramonae，小的Zonocostites和Deltoidospora adriennis的孢子。在前滨沉积物中识别出九种甲壳类十足动物，包括一个Call科，两个Cal科和六个Portunidae，以Euphylax，†Necronectes，Portunus和Scylla为代表，其生态学与边缘泻湖的海滩有关。假定这些碳酸盐环境形成的主要因素与缺乏大规模的排水系统有关，例如渐新中-中新世过渡带的亚马逊河盆地，这也可能影响了碳酸盐的生产并导致了碳酸盐岩的形成。亚马逊河沿岸初期河流系统的古粪便大量减少。据报道，少有的Zonocostites和Deltoidospora adriennis。在前滨沉积物中识别出九种甲壳类十足动物，包括一个Call科，两个Cal科和六个Portunidae，以Euphylax，†Necronectes，Portunus和Scylla为代表，其生态学与边缘泻湖的海滩有关。假定这些碳酸盐环境形成的主要因素与缺乏大规模的排水系统有关，例如渐新中-中新世过渡带的亚马逊河盆地，这也可能影响了碳酸盐的生产并导致了碳酸盐岩的形成。亚马逊河沿岸初期河流系统的古粪便大量减少。据报道，少有的Zonocostites和Deltoidospora adriennis。在前滨沉积物中识别出九种甲壳类十足动物，包括一个Call科，两个Cal科和六个Portunidae，以Euphylax，†Necronectes，Portunus和Scylla为代表，其生态学与边缘泻湖的海滩有关。假定这些碳酸盐环境形成的主要因素与缺乏大规模的排水系统有关，例如渐新中-中新世过渡带的亚马逊河盆地，这也可能影响了碳酸盐的生产并导致了碳酸盐岩的形成。亚马逊河沿岸初期河流系统的古粪便大量减少。分别以Euphylax，†Necronectes，Portunus和Scylla为代表的两个Calappidae科和六个Portunidae科，其生态学与边缘泻湖的海滩有关。假定这些碳酸盐环境形成的主要因素与缺乏大规模的排水系统有关，例如渐新中-中新世过渡带的亚马逊河盆地，这也可能影响了碳酸盐的生产并导致了碳酸盐岩的形成。亚马逊河沿岸初期河流系统的古粪便大量减少。分别以Euphylax，†Necronectes，Portunus和Scylla为代表的两个Calappidae科和六个Portunidae科，其生态学与边缘泻湖的海滩有关。假定这些碳酸盐环境形成的主要因素与缺乏大规模的排水系统有关，例如渐新中-中新世过渡带的亚马逊河盆地，这也可能影响了碳酸盐的生产并导致了碳酸盐岩的形成。亚马逊河沿岸初期河流系统的古粪便大量减少。