Dinoflagellate cyst assemblages of the Cunga - Quifangondo cenozoic formations in the Cabo São Brás section, Kwanza Basin (Angola): towards a first stratigraphic and paleoenvironmental interpretation

IF 0.7 Q4 PALEONTOLOGY

REVUE DE MICROPALEONTOLOGIE Pub Date : 2021-10-01 DOI:10.1016/j.revmic.2021.100516

Z. Pereira , M. Mendes , C. Rodrigues , N. Mulanda , M. Cacama , P.C. Nsungani

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引用次数: 2

Abstract

This work introduces one of the first palynostatigraphic study conducted on formations from the Eocene and overlying lowermost Miocene successions (Cunga and Quifangondo formations) exposed in the Onshore Kwanza Basin, Angola.

To improve the Cunga and Quifangondo formations age, new biostratigraphic correlations and palaeoenvironmental interpretations based on qualitative and quantitative analyses of organic walled dinoflagellate cysts from sedimentary rocks sampled in the Cabo de São Brás section were obtained.

Those works have revealed that the Cunga Formation could be assigned to a middle Eocene - early Oligocene age, with a palynomorph signature typical of outer neritic to oceanic environments (dominance of dinocysts with microforaminiferal linings and radiolarian pyritized fragments).

The lower Quifangondo Formation could be assigned to late Oligocene (latest Chattian) - early Miocene (Aquitanian) ages. This assumption is based on the first occurrence of Ectosphaeropsis burdigalensis, and the last occurrence of Deflandrea spp. and Chiropteridium galea. Additionally, the Chiropteridium, Distatodinium, Homotryblium, Hystrichokolpoma and Lingulodinium acme endorses a latest Chattian-early Aquitanian age to these samples. The palynomorph signature of this unit reflects an outer neritic environment.

The latest Oligocene/early Miocene Quifangondo Formation overlaps unconformably on strata of the middle Eocene to early Oligocene Cunga Formation, pointing out a hiatus between the two units.

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安哥拉宽扎盆地Cabo s o Brás剖面Cunga - Quifangondo新生代组鞭毛藻囊状组合:首次地层和古环境解释

本文介绍了首次对安哥拉陆上Kwanza盆地始新世地层和上覆的中新世下部地层(Cunga和Quifangondo地层)进行的古生物统计学研究之一。为了提高Cunga组和Quifangondo组的年龄，通过对Cabo de s o Brás剖面沉积岩中有机壁鞭毛藻囊的定性和定量分析，获得了新的生物地层对比和古环境解释。这些工作表明，康加组可归属于始新世中期-渐新世早期，具有典型的外浅海-海洋环境的岩石形态特征(以具微有孔虫衬里的藻囊和放射虫黄铁矿化碎片为主)。下祁凤岗多组可划分为晚渐新世(晚霞世)-早中新世(阿基坦世)时代。这一假设是基于最早出现的Ectosphaeropsis burdigalensis，以及最后出现的Deflandrea spp.和Chiropteridium galea。此外，Chiropteridium, Distatodinium, Homotryblium, Hystrichokolpoma和Lingulodinium acme证实了这些样本的最新chattian -早期Aquitanian年龄。该单元的形态特征反映了外部浅海环境。渐新世晚期/中新世早期的桂房岗多组与始新世中期至渐新世早期的贡加组地层不整合重叠，两者之间存在间隙。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

REVUE DE MICROPALEONTOLOGIE PALEONTOLOGY-

CiteScore

2.50

自引率

0.00%

发文量

期刊介绍： La Revue de micropaléontologie publie 4 fois par an des articles de intérêt international, consacrés à tous les aspects de la micropaléontologie. Les textes, en anglais ou en français, sont des articles originaux, des résultats de recherche, des synthèses et mises au point, des comptes rendus de réunions scientifiques et des analyses de ouvrages. La revue se veut résolument ouverte à tous les aspects de la micropaléontologie en accueillant des travaux traitant de la systématique des microfossiles (et de leurs équivalents actuels), des bactéries aux microrestes de vertébrés, et de toutes leurs applications en sciences biologiques et géologiques.