On the validity of the Macrochorobates scalabrinii Biozone (early Huayquerian Stage/Age, Late Miocene). Multi-proxy analysis of the enigmatic Arenas Blancas site (Buenos Aires Province, Argentina)

IF 0.9 4区地球科学 Q3 GEOLOGY

Andean Geology Pub Date : 2023-01-31 DOI:10.5027/andgeov50n1-3459

R. Tomassini, C. I. Montalvo, E. Beilinson, D. Barasoain, G. I. Schmidt, E. Cerdeño, A. Zurita, Ricardo Bonini, Á. Miño‐Boilini, L. Rasia, G. Gasparini

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引用次数: 5

Abstract

Arenas Blancas is a poorly known fossiliferous site located in the lower reach of the Chasicó creek (Buenos Aires Province, Argentina), with great relevance from a biostratigraphic viewpoint. The Macrochorobates scalabrinii Biozone was defined in this site, proposed as the biostratigraphic basis of the early Huayquerian Stage/Age (Late Miocene); however, the geological context and faunal record of this site have never been studied in detail. In this work, we perform a multi-proxy analysis of the Arenas Blancas site, as well as a nearby site here called Curva de la Vaca, and provide new interpretations on their origin, age, and biostratigraphy. Sedimentological, stratigraphic, and geomorphological characteristics of both sites suggest that the sequences include fluvial/alluvial deposits that represent Quaternary terraces. The taxonomic analysis of the Arenas Blancas faunal assemblage evidences the presence of 14 mammal taxa, together with some fishes, reptiles, and birds; the assemblage is correlated with the assemblage from the Cerro Azul Formation assigned to the Chasicoan Stage/Age (Late Miocene), also recovered from the lower reach of the Chasicó creek. The use of the taxa proposed in previous works to characterize the Macrochorobates scalabrinii Biozone (including this species) is not supported due to their taxonomic status and/or temporal distribution. Taphonomic evaluation indicates that the assemblage is constituted by reworked specimens; in this frame, it is proposed that fluvio/alluvial events, occurred during the Late Pleistocene-Holocene, eroded the Upper Miocene substrate and reworked fossil remains. Based on the present evidence, the Macrochorobates scalabrinii Biozone is here rejected as a valid biostratigraphic unit.

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关于阶带生物带的有效性（华克期早期/时代，中新世晚期）。神秘的布兰卡斯竞技场遗址的多代理分析（阿根廷布宜诺斯艾利斯省）

Blancas竞技场是一个鲜为人知的含化石遗址，位于Chasicócreek下游（阿根廷布宜诺斯艾利斯省），从生物地层学的角度来看具有重要意义。在该遗址中确定了Macrochorobates scalabrinii生物带，该生物带被认为是华克期早期（中新世晚期）的生物地层学基础；然而，该遗址的地质背景和动物区系记录从未得到详细研究。在这项工作中，我们对Arenas Blancas遗址以及附近一个名为Curva de la Vaca的遗址进行了多代理分析，并对它们的起源、年龄和生物地层学提供了新的解释。两个地点的沉积学、地层和地貌特征表明，该序列包括代表第四纪阶地的河流/冲积沉积物。对Arenas Blancas动物群的分类学分析表明，存在14个哺乳动物分类群，以及一些鱼类、爬行动物和鸟类；该组合与属于Chasican阶/时代（中新世晚期）的Cerro Azul组的组合相关，该组合也从Chasicócreek下游回收。由于其分类地位和/或时间分布，不支持使用先前工作中提出的分类群来表征阶带大合唱藻生物区（包括该物种）。Taphonomic评估表明，该组合是由重新加工的标本组成的；在这一框架中，认为河流/冲积事件发生在更新世晚期全新世，侵蚀了上中新世基底和改造的化石遗迹。根据目前的证据，Macrochorobates scalabrinii生物带被认为是一个有效的生物地层单元。

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来源期刊

Andean Geology 地学-地质学

CiteScore

3.90

自引率

0.00%

发文量

审稿时长

>12 weeks

期刊介绍： This journal publishes original and review articles on geology and related sciences, in Spanish or English, in three issues a year (January, May and September). Articles or notes on major topics of broad interest in Earth Sciences dealing with the geology of South and Central America and Antarctica, and particularly of the Andes, are welcomed. The journal is interested in publishing thematic sets of papers and accepts articles dealing with systematic Paleontology only if their main focus is the chronostratigraphical, paleoecological and/or paleogeographical importance of the taxa described therein.