DOI: 10.1016/j.palaeo.2015.03.029
论文题名: Environmental factors affecting the development of the Zoophycos ichnofacies in the Lower Cretaceous Río Mayer Formation (Austral Basin, Patagonia)
作者: Richiano S.
刊名: Palaeogeography, Palaeoclimatology, Palaeoecology
ISSN: 0031-0182
出版年: 2015
卷: 439 起始页码: 17
结束页码: 26
语种: 英语
英文关键词: Argentina
; Austral Basin
; Gondwana
; Lower Cretaceous
; Zoophycos ichnofacies
英文摘要: The Río Mayer Formation (Berriasian-Albian) is part of the basal infill of the Austral Basin, southwestern Gondwana. In the Los Glaciares National Park (Santa Cruz Province) seven sections were sedimentologically studied in detail. The investigated interval is mainly composed of black mudstones and shales interbedded with marls and fine-grained sandstones. The vertical distribution of these lithologies provided the basis to distinguish three major units (lower, middle and upper). In general, within the Río Mayer Formation, two different developments of the Zoophycos ichnofacies were recognized. First, in the middle unit (Valanginian-Hauterivian), this ichnofacies shows a high degree of bioturbation having a bioturbation index (BI) between 3 and 4; Zoophycos specimens are of large size, the spreiten are nearly 1. cm in height and more than 1. m in width. This ichnogenus is associated with Chondrites and Bergaueria perata. Environmentally this ichnofacies formed during a transgression, the sedimentation rates were very low and promoted the accumulation of benthic food in the outer shelf. Second, the Zoophycos ichnofacies in the upper unit (Albian) exhibits a less intense degree of bioturbation (BI between 0 and 1) and; Zoophycos is of relatively small size, the spreiten are 0.3. cm high and short. Typically are associated Ophiomorpha, Chondrites, Palaeophycus and Teredolites. When this ichnofacies formed, the prodelta margin prograded across the outer shelf and led to enhanced sedimentation rates further offshore resulting in the dilution of the nutrients. © 2015 Elsevier B.V. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/68781
Appears in Collections: 过去全球变化的重建
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作者单位: Centro de Investigaciones Geológicas (CONICET-UNLP), Calle 1 N 644, La Plata, Buenos Aires, Argentina; Cátedra de Sedimentología, Facultad de Ciencias Naturales y Museo (UNLP), Calle 122 y 60, La Plata, Buenos Aires, Argentina
Recommended Citation:
Richiano S.. Environmental factors affecting the development of the Zoophycos ichnofacies in the Lower Cretaceous Río Mayer Formation (Austral Basin, Patagonia)[J]. Palaeogeography, Palaeoclimatology, Palaeoecology,2015-01-01,439