Application of low-temperature thermochronology to brazilian impact structure

• Grant number: 11/22864-1
• Support Opportunities: Scholarships in Brazil - Doctorate
• Start date: April 01, 2012
• End date: March 31, 2016
• Field of knowledge: Physical Sciences and Mathematics - Geosciences - Geology
• Principal Investigator: Alvaro Penteado Crósta
• Grantee: Mariana Velcic Maziviero
• Host Institution: Instituto de Geociências (IG). Universidade Estadual de Campinas (UNICAMP). Campinas , SP, Brazil

Abstract

There are 182 confirmed impact structures known on Earth. Determining ages for impact structures is important for (1) correlating causes and effects on the bio- and geosphere of catastrophic processes, (2) better constraining the impactor flux through geological time and evaluation of potential impact periodicity, (3) calibrating the absolute chronostratigraphic time scale, and (4) calibrating the age of within-crater continental sedimentary deposits. In most impact structures the main radiometric dating of impact melt rocks or impact glasses are U-Pb and Ar-Ar. In the absence of such melts, e.g. due erosive processes, low temperature thermochronology done by apatite and zircon fission-track and (U-Th)/He analysis may provide the thermochronological ages in association with the impact and insights into the timing of thermal events post-shock. In this work we propose to apply low-temperature thermochronology to four brazilian impact structures: Araguainha (MT), Serra da Cangalha (TO), Riachão (MA), and Vargeão (SC). These structures are located in different impact lithologies, have diameters between about 4 and 40 km, and varying degrees of erosion.

Academic Publications

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

MAZIVIERO, Mariana Velcic. Dating brazilian impact structures using LA-ICP-MS zircon fission track and (U-Th)/He. 2016. Doctoral Thesis - Universidade Estadual de Campinas (UNICAMP). Instituto de Geociências Campinas, SP.