Please use this identifier to cite or link to this item:
https://hdl.handle.net/2440/126523
Type: | Thesis |
Title: | Crustal thickening in the early Mesoarchaean? Insight from ancient high-pressure metamorphism in SW India |
Author: | Bockmann, M. J. |
Issue Date: | 2017 |
School/Discipline: | School of Physical Sciences |
Abstract: | Eoarchaean–Mesoarchaean crust typically registers uniformly high T/P metamorphism, thought to reflect a stagnant lid tectonic regime in the primitive Earth. However, we report evidence for high-pressure granulite metamorphism from the early Mesoarchaean in south-west India. Garnet-kyanite-rutile-bearing assemblages in felsic granulites record minimum peak metamorphic conditions of 13.1 kbar and 940oC. LA–ICP–MS analysis of zircon and monazite U–Pb isotopes and trace elements indicate high-pressure granulite facies metamorphism took place at ca. 3.15 Ga. Apparent thermal gradients of 72°C/kbar correspond to burial beneath ~45km of continental crust. The preservation of crust under these conditions is not expected this early in the Earth’s history under the conditions proposed for the stagnant lid regime. This implies that the transition toward a more modern style tectonic regime may have taken place earlier than what is currently recognised. |
Dissertation Note: | Thesis (B.Sc.(Hons)) -- University of Adelaide, School of Physical Sciences, 2017 |
Where: | Southwest India |
Keywords: | Honours; Geology; crustal thickening; Mesoarchaean; metamorphism; high-pressure; India; U–Pb geochronology; pseudosection |
Description: | This item is only available electronically. |
Provenance: | This electronic version is made publicly available by the University of Adelaide in accordance with its open access policy for student theses. Copyright in this thesis remains with the author. This thesis may incorporate third party material which has been used by the author pursuant to Fair Dealing exceptions. If you are the author of this thesis and do not wish it to be made publicly available, or you are the owner of any included third party copyright material you wish to be removed from this electronic version, please complete the take down form located at: http://www.adelaide.edu.au/legals |
Appears in Collections: | School of Physical Sciences |
Files in This Item:
File | Size | Format | |
---|---|---|---|
BockmannMJ2017_Hons.pdf | 8.86 MB | Adobe PDF | View/Open |
Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.