25-Nov-2015 01:48

Geochronology dating techniques

In this article, we present the current methodology used at the CPGeo-IGc-USP U-Pb laboratory, the improvements on ID-TIMS method, and report high-precision U-Pb data from zircon, monazite, epidote, titanite, baddeleyite and rutile from different rock types of several domains of the Brazilian south-southeast area, Argentina and Uruguay.

Esta sistemática proporciona resultados bastante confiáveis e precisos na determinação das idades de eventos geológicos superpostos.Entretanto, o comportamento de sistema aberto como perda de Pb, problemas de herança isotópica e processos de metamictização, nos permite o entendimento do poder e limitação da geocronologia e termocronologia U-Pb.Neste artigo apresentamos a metodologia atualmente utilizada no Laboratório U-Pb do CPGeo-IGc-USP, as melhorias atingidas na técnica ID-TIMS e alguns dados obtidos em zircão, epídoto, titanita, baddeleyita e rutilo de diferentes tipos de rochas de alguns domínios da região sul-sudeste brasileira e da Argentina e Uruguai.The Centro de Pesquisas Geocronológicas (Center for Geochronological Research - CPGeo) is one of the interdepartmental centers of the Instituto de Geociências(IG) of São Paulo University.Since 1964, the Interdepartmental Laboratory of Isotopic Geology focus the study of the Earth's geologic processes, dealing with themes such as plate tectonics, plutonism, volcanism, sedimentary rocks, tectono-thermal evolution, and more recently environmental studies.and is equipped with seven mass spectrometers for radiogenic and stable isotope analysis.

Among the up-to-date pieces of equipment there are three solid-source mass spectrometers (two VG 354 and a Finnigan MAT 262) and two gaseous-source (a MAP 215 Ar-Ar and a Europa GEO 20/20).

An internal network (GEOCRON) links all laboratories.

Since 1964, the Center for Geochronological Research – CPGeo, one of the interdepartmental centers of the Instituto de Geociências (IG) of São Paulo University, has developed studies related to several geological processes associated with different rock types.

Thermal Ionization Mass Spectrometry Isotopic Dilution (ID-TIMS) has been the technique widely used in the CPGeo U-Pb Laboratory.

It provides reliable and accurate results in age determination of superposed events.

However, the open-system behavior such as Pb-loss, the inheritance problem and metamictization processes allow and impel us to a much richer understanding of the power and limitations of U-Pb geochronology and thermochronology.

Profile for geochronology dating techniques:

geochronology dating techniques-19geochronology dating techniques-26geochronology dating techniques-61geochronology dating techniques-64

Leave a Reply

Your email address will not be published. Required fields are marked *

One thought on “geochronology dating techniques”