Modelling the effect of arbitrary P-T-t histories on argon diffusion in minerals using the MacArgon program for the Apple Macintosh

Macarbon.com

Abstract

Argon diffusion in mineral grains has been numerically modelled using P-T-t histories that may be relevant to multiply metamorphosed orogenic terranes and for rocks that have resided at high ambient temperatures in the Earth's crust for long durations. Download data card modems driver. The MacArgon program generates argon concentration profiles in minerals assuming argon loss occurs via volume diffusion. It can be run on an Apple Macintosh computer, with arbitrary P-T-t histories used as input. Finite-difference equations are used in the calculation of ⁴⁰ Giesecke & devrient driver download for windows. Ar∗ concentration profiles across individual diffusion domains. The associated MacSpectrometer generates model spectra after a P-T-t history has been specified. The form of model {⁴⁰Ar }/{³⁹Ar } apparent age spectra suggests that considerable caution needs to be exercised in the use of the closure temperature concept and in the interpretation of the significance of plateaux observed in many {⁴⁰Ar }/{³⁹Ar } apparent age spectra, particularly in cases involving metamorphic rocks, where complex P-T-t histories might apply. Although modelled spectra cannot be directly compared to experimentally determined {⁴⁰Ar }/{³⁹Ar } age spectra, especially when hydrous phases are involved or in cases where loss of argon has not occurred via volume diffusion, they do provide insight into theoretically expected age spectra for samples that have experienced complex P-T-t histories.

MacArgon can be obtained by e-mail from MacArgon artemis.earth.monash.edu.au with enquiries to gordonartemis.earth.monash.edu.au

Lister moved to ANU to join the Research School of Earth Sciences at ANU in 2003. Dmx4all usb devices driver download for windows 10. His efforts have been focussed on: 1) structural geology on the planet scale; 2) diffusion theory for argon geochronology in order to allow precise dating of the effects caused by rock deformation, and in order that field observations can be brought to constrain the timing of the large-scale.

Macaroni With The Chicken Strips

Macaroni Grill

Publication:

Pub Date:

March 1996

DOI:

10.1016/0040-1951(95)00059-3

Bibcode:

1996Tectp.253..83L

S., and Baldwin, S. Modelling the effect of arbitrary P-T-t histories on argon diffusion in minerals using the MacArgon program for the Apple Macintosh. Tectonophysics, 253, 83–109. CrossRef Google Scholar. MacArgon program for iterative forward modelling. In this way we were able to constrain the shape of tempera-ture 40time (T t) histories that allow observed Ar/39Ar age spectra to be approximated, assuming release by dif-fusional processes alone. GEOCHRONOLOGY The Capoas Granite (Figure 1) is a fresh equigranular to.