Identification and importance of critical depositional gaps in pitfall cave environments: The fossiliferous deposit of Cuvieri Cave, eastern Brazil

Author(s)

Hubbe, Alex ^{[1, 2]} ; Haddad-Martim, Paulo M. ^[2] ; Hubbe, Mark ^[3] ; Mayer, Elver L. ^[2] ; Strauss, Andre ^[4] ; Auler, Augusto S. ^[1] ; Pilo, Luis B. ^[1] ; Neves, Walter A. ^[2]

Affiliation

^[1] Inst Carste, BR-30360260 Belo Horizonte, MG - Brazil

^[2] Univ Sao Paulo, Inst Biociencias, Lab Estudos Evolut Humanos, Dept Genet & Biol Evolut, BR-05508090 Sao Paulo - Brazil

^[3] Univ Catolica Norte, Inst Invest Arqueol & Museo, San Pedro De Atacama 1410000 - Chile

^[4] Max Planck Inst Evolutionary Anthropol, Dept Human Evolut, D-04103 Leipzig - Germany

• Document type: Journal article
• Source: PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY; v. 312, n. 1-2, p. 66-78, DEC 1 2011.
• Web of Science Citations: 15

Abstract

The majority of extinct Brazilian late Quaternary mammal (i.e. megafauna) remains comes from cave deposits and was retrieved through excavations lacking detailed stratigraphical context. This poses a major problem since these deposits present multifaceted processes of formation. Based on the meticulous excavation of a pitfall site within Cuvieri Cave, Minas Gerais, eastern Brazil, this article describes a critical, albeit subtle, temporal discontinuity between different fossiliferous sedimentary facies and discusses its significance to the contextualization of the paleontological remains recovered from the site. The discontinuity was described based on sedimentary analyses, bone deposition processes, taxonomy and AMS radiocarbon chronology. Two facies were distinguished and named according to their color and texture: an upper dark brown silt-loam (BSL) and a lower dark reddish brown silt-loam (RBSL). Besides color differences, they present differences in grain size distribution and chemical composition. These analyses show that the RBSL has in its composition only half the sand and one third more the silt than BSL It also shows that mean percent values for the RBSL in comparison to the BSL are higher for silica (4235 versus 15.80), aluminum (18.63 versus 7.58) and iron (8.45 versus 3.79) and lower for calcium (10.07 versus 36.14) and volatiles (13.86 versus 30.10). These differences are attributed to changes in sediment source and entrance route. Differences were also observed in the faunal remain analyses. RBSL has abundant megafauna remains originally deposited within this facies, while the scarce megafauna material found in BSL is the result of mixing processes. Despite these differences, animal entrapment is considered the best scenario to explain bone accumulation in both facies. AMS radiocarbon dates indicate that the BSL was deposited during the Holocene, with dates ranging from 8580 cal yr BP to the present, while the RBSL deposition dates to the Holocene/Pleistocene transition (13,600-10,660 cal yr BP). Radiocarbon dating also indicates that the subtle erosional surface that limits both facies represents a temporal gap between a minimum age of 8.4 cal kyr BP and a maximum age of 11.0 cal kyr BP. The recognition of this discontinuity allows for a more accurate interpretation of bone accumulation, enabling the differentiation of faunal assemblages that might otherwise be considered part of a continuum. (C) 2011 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 09/03753-4 - Formation processes of a fossiliferous pitfall deposit in Gruta Cuvieri (MG): taxonomy, taphonomy and spacial distribution of mammal fossils from the Pleistocene
• Grantee: Elver Luiz Mayer
• Support type: Scholarships in Brazil - Master
• FAPESP's process: 04/01321-6 - Origins and microevolution of man in the Americas: a paleoanthropological approach (III)
• Grantee: Walter Alves Neves
• Support type: Research Projects - Thematic Grants
• FAPESP's process: 08/51747-0 - Mortuary practices characterization of the pre-historic hunter-gatherers from Lapa do Santo, Lagoa Santa (MG)
• Grantee: André Menezes Strauss
• Support type: Scholarships in Brazil - Master