Shell sclerochronology and stable isotopes of the bivalve Anomalocardia flexuosa (Linnaeus, 1767) from southern Brazil: Implications for environmental and archaeological studies

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Colonese, Andre Carlo ; Netto, Sergio Antonio ; Francisco, Andre Silva ; DeBlasis, Paulo ; Villagran, Ximena S. ; Rocha Ponzoni, Raquel de Almeida ; Hancock, Y. ; Hausmann, Niklas ; Eloy de Farias, Deisi Sunderlick ; Prendergast, Amy ; Schoene, Bernd R. ; da Cruz, Francisco William ; Fonseca Giannini, Paulo Cesar

• Document type: Journal article
• Source: PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY; v. 484, p. 15-pg., 2017-10-15.

Abstract

This study presents the first stable isotopic and sclerochronological calibration of the bivalve Anomalocardia flexuosa (Linnaeus, 1767) in relation to environmental variables in a subtropical coastal area of southern Brazil. We investigate incremental shell growth patterns and delta O-18 and delta C-13 values of modern specimens collected alive from the Laguna Lagoonal System (LLS). Shells of Anomalocardia flexuosa are also one of the main biological components of pre-Columbian archaeological shell mounds and middens distributed along the Brazilian coastline. We therefore selected archaeological specimens from a local late Holocene shell mound (Cabecuda) to compare their stable carbon and oxygen isotope values with those of modern specimens. Shell growth increments, delta O-18 and delta C-13 values respond to a complex of environmental conditions, involving, for example, the effects of temperature and salinity. The isotopic information extracted from archaeological specimens from Cabecuda shell midden in the LLS indirectly indicates that environmental conditions during the late Holocene were different from present day. In particular, intra-shell delta O-18 and delta C-13 values of archaeological shells reveal a stronger marine influence at 3 Ka cal BP, which is in contrast to the seasonal freshwater/seawater balance that currently prevails at the LLS. (C) 2017 Elsevier B.V. All rights reserved. (AU)

• FAPESP's process: 04/11038-0 - Sambaquis and landscape: modeling cultural and natural relationships at the Brazilian southern shores, Santa Catarina
• Grantee: Paulo Antônio Dantas de Blasis
• Support Opportunities: Research Projects - Thematic Grants