CaltechAUTHORS
  A Caltech Library Service

Ultrahigh-temperature osumilite gneisses in southern Madagascar record combined heat advection and high rates of radiogenic heat production in a long-lived high-T orogen

Holder, Robert M. and Hacker, Bradley R. and Horton, Forrest and Rakotondrazafy, A. F. Michel (2018) Ultrahigh-temperature osumilite gneisses in southern Madagascar record combined heat advection and high rates of radiogenic heat production in a long-lived high-T orogen. Journal of Metamorphic Geology, 36 (7). pp. 855-880. ISSN 0263-4929. https://resolver.caltech.edu/CaltechAUTHORS:20180815-155406296

[img] PDF (Appendix S1-S3; Figures S1-S2) - Supplemental Material
See Usage Policy.

1820Kb
[img] MS Excel (Tables S1-S8) - Supplemental Material
See Usage Policy.

744Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20180815-155406296

Abstract

We report the discovery of osumilite in ultrahigh‐temperature (UHT) metapelites of the Anosyen domain, southern Madagascar. The gneisses equilibrated at ~930°C/0.6 GPa. Monazite and zircon U–Pb dates record 80 Ma of metamorphism. Monazite compositional trends reflect the transition from prograde to retrograde metamorphism at 550 Ma. Eu anomalies in monazite reflect changes in fO_2 relative to quartz–fayalite–magnetite related to the growth and breakdown of spinel. The ratio Gd/Yb in monazite records the growth and breakdown of garnet. High rates of radiogenic heat production were the primary control on metamorphic grade at the regional scale. The short duration of prograde metamorphism in the osumilite gneisses (<29 ± 8 Ma) suggests that a thin mantle lithosphere (<80 km) or advective heating may have also been important in the formation of this high‐T, low‐P terrane.


Item Type:Article
Related URLs:
URLURL TypeDescription
https://doi.org/10.1111/jmg.12316DOIArticle
ORCID:
AuthorORCID
Holder, Robert M.0000-0002-1119-6905
Additional Information:© 2018 John Wiley & Sons Ltd. Issue Online: 02 August 2018; Version of Record online: 26 April 2018; Accepted manuscript online: 01 April 2018; Manuscript accepted: 25 March 2018; Manuscript received: 10 September 2017. Funding Information: Division of Earth Sciences. Grant Number: NSF‐EAR‐1348003. University of California, Santa Barbara. Grant Number: NSF‐EAR‐1348003.
Funders:
Funding AgencyGrant Number
NSFEAR-1348003
Subject Keywords:heat advection; Madagascar; osumilite; radiogenic heat production; ultrahigh‐temperature metamorphism
Issue or Number:7
Record Number:CaltechAUTHORS:20180815-155406296
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20180815-155406296
Official Citation:Holder RM, Hacker BR, Horton F, Rakotondrazafy AFM. Ultrahigh‐temperature osumilite gneisses in southern Madagascar record combined heat advection and high rates of radiogenic heat production in a long‐lived high‐T orogen. J Metamorph Geol. 2018;36:855–880. https://doi.org/10.1111/jmg.12316
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:88835
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:16 Aug 2018 00:15
Last Modified:03 Oct 2019 20:10

Repository Staff Only: item control page