Dating of shells and sediments from Santa Marta II Shellmound, Laguna, Santa Catarina

• Grant number: 17/12845-6
• Support Opportunities: Scholarships in Brazil - Master
• Start date: October 01, 2017
• End date: December 31, 2019
• Field of knowledge: Physical Sciences and Mathematics - Physics - Nuclear Physics
• Principal Investigator: Shigueo Watanabe
• Grantee: Letícia Mendes de Oliveira
• Host Institution: Instituto de Pesquisas Energéticas e Nucleares (IPEN). Secretaria de Desenvolvimento Econômico (São Paulo - Estado). São Paulo , SP, Brazil
• Associated research grant: 14/03085-0 - Quaternary geochronology of Southeastern and Southern coast of Brazil, AP.TEM
• Associated scholarship(s): 18/19951-9 - Dating of aragonite shells and sediments by ESR method of the Shellmound Santa Marta II, Santa Catarina, Brazil, BE.EP.MS

Abstract

The pre-historic occupation of the Brazilian coast by Tupi-Guarani coming from the North occurred more than five to six thousand years ago. For those living in sea coast, molluscs, fishes, and other marine edibles were regular feeds, and the remains, mainly the shells, were heaped up, obtaining, in the course of time, mounds of small and enormous proportions, called Shellmounds, that became part of the landscape of the Coastal plain, particularly, with emphasis in the south and southeast coast. In the states of Santa Catarina, in the region of Tubarão, Laguna, Jaguaruna and São Paulo, in Ilha Comprida, there are the largest Sambaquis, many of them reaching 8 to 10 meters in height and a base area of about 400,000 m². In this work, samples will be collected from Sambaqui Santa Marta II, near Laguna, Santa Catarina. The samples will be collected from the base part introducing PVC tubes with 3 cm in diameter and 8 to 12 meters in length. Sediments collected will be used to determine the annual dose rate, Dan, and selecting complete or less fragmented shells, for dating. It is necessary to prepare the sample before the analysis, a chemical treatment with H2O2 will be made, and, after drying, the shells will be pulverized and sieved retaining the grains between 0,080 mm and 0,180 mm diameter. The samples will be separated into about 10 portions, each about 15mg to be irradiated with gamma rays of doses of 10, 20, 30, 40, 50, 60, 70, 80, 90, and 100 Gy. The irradiated samples will be analyzed with Thermluminescence equipment. The TL intensity will be plotted against the dose and the calculations will be made to obtain the called accumulated dose, Dac, and finally, age = Dac/Dan. (AU)

Academic Publications

(References retrieved automatically from State of São Paulo Research Institutions)

OLIVEIRA, Letícia Mendes de. Dating of shells and sediments from Giant Shellmound Santa Marta II, Laguna, Santa Catarina. 2019. Master's Dissertation - Universidade de São Paulo (USP). Instituto de Pesquisas Energéticas e Nucleares (IPEN/BT) São Paulo.