Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin

The Chiang Mai basin is the largest of a zone of rift basins that define the Northern Thailand Basin and Range Province. This province lies within the Shan Thai block of NW Indochina that extruded out of the India-Asia collision. The Mae Rim Formation crops out along the western side of the Chiang M...

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Main Authors: Brady P. Rhodes, Richard Conejo, Teekayu Benchawan, Susan Titus, Ross Lawson
Format: Journal
Published: 2018
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http://cmuir.cmu.ac.th/jspui/handle/6653943832/62183
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spelling th-cmuir.6653943832-621832018-09-11T09:23:15Z Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin Brady P. Rhodes Richard Conejo Teekayu Benchawan Susan Titus Ross Lawson Earth and Planetary Sciences The Chiang Mai basin is the largest of a zone of rift basins that define the Northern Thailand Basin and Range Province. This province lies within the Shan Thai block of NW Indochina that extruded out of the India-Asia collision. The Mae Rim Formation crops out along the western side of the Chiang Mai basin. Detachment faults border the Mae Rim Formation on the west and north and juxtapose it against the high-grade Western Ranges metamorphic complex and its low-grade cover of Palaeozoic Shan-Thai rocks. Understanding the age and tectonic relationships between rifting, detachment faulting, ductile shear, uplift and exhumation of the Western Ranges metamorphic complex is critical to understanding the underlying deformational mechanisms that accompanied Indochina's extrusion. To better understand the palaeogeography of the Chiang Mai basin and its relationship to the Western Ranges metamorphic complex, several partial sections were measured, and palaeocurrent and clast-composition data from the Mae Rim Formation were collected. Poorly organized, immature conglomerates of the Mae Rim Formation probably represent alternating debris flows, sheet-flood, and braided channel deposits. The Mae Rim Formation probably accumulated in range-front alluvial fans, and graded rapidly into lacustrine deposits within the buried central part of the Chiang Mai basin. Except for the youngest strata, where gneissic clasts predominate, virtually all clasts in the Mae Rim Formation came from the low-grade metasedimentary rocks that form the cover of the Western Ranges metamorphic complex. Imbricated clasts indicate eastward palaeocurrents away from the metamorphic complex. Most of the Mae Rim Formation accumulated during the uplift of the Western Ranges but before erosion had breached the detachment fault. These new data suggest a tectonic history for the Chiang Mai basin that involved distinct phases of extension from late Oligocene to Quaternary, with at least two intervening periods of basin inversion. 2018-09-11T09:23:15Z 2018-09-11T09:23:15Z 2005-01-01 Journal 00167649 2-s2.0-13344260667 10.1144/0016-764903-128 https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=13344260667&origin=inward http://cmuir.cmu.ac.th/jspui/handle/6653943832/62183
institution Chiang Mai University
building Chiang Mai University Library
country Thailand
collection CMU Intellectual Repository
topic Earth and Planetary Sciences
spellingShingle Earth and Planetary Sciences
Brady P. Rhodes
Richard Conejo
Teekayu Benchawan
Susan Titus
Ross Lawson
Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin
description The Chiang Mai basin is the largest of a zone of rift basins that define the Northern Thailand Basin and Range Province. This province lies within the Shan Thai block of NW Indochina that extruded out of the India-Asia collision. The Mae Rim Formation crops out along the western side of the Chiang Mai basin. Detachment faults border the Mae Rim Formation on the west and north and juxtapose it against the high-grade Western Ranges metamorphic complex and its low-grade cover of Palaeozoic Shan-Thai rocks. Understanding the age and tectonic relationships between rifting, detachment faulting, ductile shear, uplift and exhumation of the Western Ranges metamorphic complex is critical to understanding the underlying deformational mechanisms that accompanied Indochina's extrusion. To better understand the palaeogeography of the Chiang Mai basin and its relationship to the Western Ranges metamorphic complex, several partial sections were measured, and palaeocurrent and clast-composition data from the Mae Rim Formation were collected. Poorly organized, immature conglomerates of the Mae Rim Formation probably represent alternating debris flows, sheet-flood, and braided channel deposits. The Mae Rim Formation probably accumulated in range-front alluvial fans, and graded rapidly into lacustrine deposits within the buried central part of the Chiang Mai basin. Except for the youngest strata, where gneissic clasts predominate, virtually all clasts in the Mae Rim Formation came from the low-grade metasedimentary rocks that form the cover of the Western Ranges metamorphic complex. Imbricated clasts indicate eastward palaeocurrents away from the metamorphic complex. Most of the Mae Rim Formation accumulated during the uplift of the Western Ranges but before erosion had breached the detachment fault. These new data suggest a tectonic history for the Chiang Mai basin that involved distinct phases of extension from late Oligocene to Quaternary, with at least two intervening periods of basin inversion.
format Journal
author Brady P. Rhodes
Richard Conejo
Teekayu Benchawan
Susan Titus
Ross Lawson
author_facet Brady P. Rhodes
Richard Conejo
Teekayu Benchawan
Susan Titus
Ross Lawson
author_sort Brady P. Rhodes
title Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin
title_short Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin
title_full Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin
title_fullStr Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin
title_full_unstemmed Palaeocurrents and provenance of the Mae Rim Formation, Northern Thailand: Implications for tectonic evolution of the Chiang Mai basin
title_sort palaeocurrents and provenance of the mae rim formation, northern thailand: implications for tectonic evolution of the chiang mai basin
publishDate 2018
url https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=13344260667&origin=inward
http://cmuir.cmu.ac.th/jspui/handle/6653943832/62183
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