Hf isotopes in zircon reveal contrasting sources and crystallisation histories for alkaline to peralkaline granites of Temora, southeastern Australia

Kemp, A.I.S., Wormald, R.J., Whitehouse, M.J., and Price, R.C. (2005) Hf isotopes in zircon reveal contrasting sources and crystallisation histories for alkaline to peralkaline granites of Temora, southeastern Australia. Geology, 33 (10). pp. 797-800.

[img] PDF
Restricted to Repository staff only

View at Publisher Website: http://dx.doi.org/10.1130/G21706.1

Abstract

Peralkaline granites exhibit the hallmark features of A-type igneous rocks, but strongly differentiated chemistry and intense hydrothermal alteration camouflage their ultimate origins. We present the first in situ Hf isotope data from zircons of peralkaline granites, aimed at clarifying the protoliths of these plutons and their genetic relationship to associated metaluminous/weakly peraluminous granites. This study used rocks of the Devonian Narraburra Complex in southeastern Australia, and found that correlations between Hf isotopes and trace element ratios reveal fundamentally different origins for the nonperalkaline and peralkaline granites. The latter have a depleted mantle-like ancestry, whereas a weakly peraluminous rock formed from melts of older arc crust that were modified by interaction with juvenile, probably alkaline magmas. Juxtaposition of crust- and mantle-derived magmas reflects the high heat flow and lithosphere-scale faults associated with continental extension, and explains the diversity of A-type granites.

Item ID: 4697
Item Type: Article (Refereed Research - C1)
Keywords: peralkaline; granite; zircon; Hf isotope
ISSN: 1943-2682
Date Deposited: 15 Jul 2009 04:23
Downloads: Total: 4
Last 12 Months: 1
More Statistics

Actions (Repository Staff Only)

Item Control Page Item Control Page