Constraining the timing of shale detachment faulting: A geochemical approach
Rowan Hansberry
(1)
,
Horst Zwingmann
(2)
,
Stefan Loehr
(3)
,
Alan Collins
(4)
,
Rosalind King
(1)
,
Christopher Morley
(5)
,
Russell Drysdale
(6, 7)
Résumé
K-Ar dating of illite in fault gouges is a useful tool for constraining the timing of brittle fault movement; however, this can be problematic in fault gouges hosted in clay-rich rocks due to the influence of host-rock material. Therefore, this study employs a multianalytical geochemical approach to unravel the influence of host-rock mineralogy, as well as fault zone development, on ages from fault-gouge samples in a shale detachment zone. K-Ar dating of the (3)2 mu m fraction of 6 samples from the Sap Bon Formation detachment zone and associated fault zones in the Khao Khwang fold-thrust belt of central Thailand yielded an age range of 262 +/- 5.4 to 208 +/- 4.6 Ma. Carbon and oxygen stable isotope analysis along with X-ray diffraction mineralogy indicate that the samples with the youngest K-Ar ages are characterized by higher grade clay mineralogy, and hotter, orogenic fluid temperatures. Using these proxies and comparison to existing geochronology of the study area, we correlated K-Ar illite ages to one of three stages of fault zone evolution: detrital, diagenetic (burial), and authigenic (fault movement). The youngest K-Ar dates in the Sap Bon Formation are contemporaneous with recently published zircon province data indicating that faulting and detachment zone formation in the Sap Bon Formation were occurring by the mid-Late Triassic, with deformation continuing as late as the Rhaetian.
Domaines
Milieux et Changements globaux Biodiversité et Ecologie Environnement et Société Ingénierie de l'environnement GéographieFormat du dépôt | Notice |
---|---|
Type de dépôt | Article dans une revue |
Titre |
en
Constraining the timing of shale detachment faulting: A geochemical approach
|
Résumé |
en
K-Ar dating of illite in fault gouges is a useful tool for constraining the timing of brittle fault movement; however, this can be problematic in fault gouges hosted in clay-rich rocks due to the influence of host-rock material. Therefore, this study employs a multianalytical geochemical approach to unravel the influence of host-rock mineralogy, as well as fault zone development, on ages from fault-gouge samples in a shale detachment zone. K-Ar dating of the (3)2 mu m fraction of 6 samples from the Sap Bon Formation detachment zone and associated fault zones in the Khao Khwang fold-thrust belt of central Thailand yielded an age range of 262 +/- 5.4 to 208 +/- 4.6 Ma. Carbon and oxygen stable isotope analysis along with X-ray diffraction mineralogy indicate that the samples with the youngest K-Ar ages are characterized by higher grade clay mineralogy, and hotter, orogenic fluid temperatures. Using these proxies and comparison to existing geochronology of the study area, we correlated K-Ar illite ages to one of three stages of fault zone evolution: detrital, diagenetic (burial), and authigenic (fault movement). The youngest K-Ar dates in the Sap Bon Formation are contemporaneous with recently published zircon province data indicating that faulting and detachment zone formation in the Sap Bon Formation were occurring by the mid-Late Triassic, with deformation continuing as late as the Rhaetian.
|
Auteur(s) |
Rowan Hansberry
1
, Horst Zwingmann
2
, Stefan Loehr
3
, Alan Collins
4
, Rosalind King
1
, Christopher Morley
5
, Russell Drysdale
6, 7
1
University of Adelaide
( 116469 )
- Adelaide, South Australia, 5005 Australia
- Australie
2
Kyoto University
( 237161 )
- Yoshidahonmachi, Sakyo Ward, Kyoto, Kyoto Prefecture 606-8501
- Japon
3
Macquarie University [Sydney]
( 539566 )
- Sydney, NSW, 2109, Australia
- Australie
4
King‘s College London
( 327716 )
- Strand Campus, London WC2R 2LS
- Royaume-Uni
5
CMU -
Chiang Mai University
( 301779 )
- 239, Huay Kaew Road, Muang District ,Chiang Mai
- Thaïlande
6
University of Melbourne
( 306322 )
- Parkville VIC 3010
- Australie
7
EDYTEM -
Environnements, Dynamiques et Territoires de Montagne
( 20150 )
- Université de Savoie, Campus scientifique, 73376 Le Bourget du Lac cedex
- France
|
Licence |
Paternité
|
Date de publication |
2017-06-01
|
Page/Identifiant |
431-440
|
Date de publication électronique |
2017-06-27
|
Langue du document |
Anglais
|
Nom de la revue |
|
Vulgarisation |
Non
|
Comité de lecture |
Oui
|
Audience |
Internationale
|
Volume |
9
|
Numéro |
3
|
Référence interne |
|
Domaine(s) |
|
DOI | 10.1130/L612.1 |
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