Towards an actualistic view of the Crato Konservat-Lagerstätte paleoenvironment : a new hypothesis as an Early Cretaceous (Aptian) equatorial and semi-arid wetland.
Nenhuma Miniatura disponível
Data
2021
Título da Revista
ISSN da Revista
Título de Volume
Editor
Resumo
An alternative hypothesis concerning the paleoecological and paleoenvironmental depositional conditions of the
Crato Konservat-Lagerstatte ̈ (CKL), Crato Formation, Aptian, NE Brazil, one of the most extraordinary Gondwana
fossil sites, is proposed. Following an actualistic approach, the ecology of extant relatives of the most abundant
and diverse fossil groups recorded in the CKL (i.e., vascular plants, arthropods, fishes, and tetrapods) is
considered. Data is based on an extensive literature review followed by a re-examination of recently collected
fossils. This approach allowed a detailed appraisal of the stratigraphic/ecological distribution of the main fossil
groups preserved in the CKL. Plant and animal groups are recorded in three main stratigraphic intervals, named
Intervals I–III in ascending order. Most fossils are to be considered autochthonous to parautochthonous and have
been preserved in distinct stages of base-level fluctuations within a shallow lacustrine depositional system,
subject to periodic flooding in large, depressed areas. Exceptional preservation in such environments was
mediated by microbially-induced processes (i.e., microbial mat entombment), mostly in the coastal areas of the
alkaline lake. Based on the distinct sedimentary facies and autecological attributes of dominant paleo-
bioindicators, a new paleoenvironmental model for the CKL is proposed, encompassing a seasonal, semi-arid,
shallow lacustrine wetland. Faunal and floral content were ecologically arranged in long-lasting aquatic
zones, surrounded by periodically flooded mesophytic ecotones and outer xeric habitats, as in the modern
alkaline lake Chad in Africa. Our data show the relevance of multiproxy analyses (i.e., paleontological, sedi-
mentological, geochemical, and stratigraphic) of exceptional fossil sites for assessing paleoenvironmental con-
ditions in depositional settings subject to continuous base-level changes, such as those existing in complex,
present-day wetland ecosystems. The recognition of key parameters in ancient wetlands is of great importance
concerning the formation of non-marine Konservat-Lagerst ̈
atten in the geological record.
Descrição
Palavras-chave
Crato Formation, Exceptional preservation, Wetlands
Citação
RIBEIRO, A. C. et al. Towards an actualistic view of the Crato Konservat-Lagerstätte paleoenvironment: a new hypothesis as an Early Cretaceous (Aptian) equatorial and semi-arid wetland. Earth-Science Reviews, v. 216, artigo 103573, 2021. Disponível em: <https://www.sciencedirect.com/science/article/pii/S0012825221000726>. Acesso em: 29 abr. 2022.