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Tectonic Mode Switches Recorded at the Northern Edge of the Australian Plate During the Pliocene and Pleistocene
White L.T.b, Hall R.b, Gunawan I.c, Kohn B.d
a GeoQuEST Research Centre, School of Earth, Atmospheric and Life Sciences, University of Wollongong, Wollongong, Australia
b Southeast Asia Research Group, Department of Earth Sciences, Royal Holloway University of London, Egham, United Kingdom
c Institut Teknologi Bandung, Bandung, Indonesia
d School of Earth Sciences, University of Melbourne, Melbourne, Australia
[vc_row][vc_column][vc_row_inner][vc_column_inner][vc_separator css=”.vc_custom_1624529070653{padding-top: 30px !important;padding-bottom: 30px !important;}”][/vc_column_inner][/vc_row_inner][vc_row_inner layout=”boxed”][vc_column_inner width=”3/4″ css=”.vc_custom_1624695412187{border-right-width: 1px !important;border-right-color: #dddddd !important;border-right-style: solid !important;border-radius: 1px !important;}”][vc_empty_space][megatron_heading title=”Abstract” size=”size-sm” text_align=”text-left”][vc_column_text]©2018. American Geophysical Union. All Rights Reserved.We report new data from medium-high grade metamorphic rocks found at the northern margin of the Lengguru Fold Belt in West Papua. The study involved a systematic analysis of cross-cutting structures to establish the relative timing of deformation, together with isotopic dating to define when these tectono-thermal events occurred. These data show that the region underwent multiple episodes of deformation within the last six million years. Metamorphic mineral growth was associated with the development of ductile shear zones. This episode occurred during a phase of crustal stretching associated with the formation of a metamorphic core complex. Metamorphic zircon growth at 4.9 to 5.3 Ma was documented in two of the dated samples. These data are interpreted to postdate the peak pressure and temperature conditions of the phase of regional crustal stretching. The shear fabrics associated with the metamorphic core complex were later overprinted by at least two generations of folds. The change in mode from crustal extension to shortening reflects a tectonic mode switch. A subsequent mode switch is documented by numerous brittle extensional faults that cross-cut the earlier formed ductile fabrics. We interpret ca. 0.75–1.51 Ma (U–Th)/He age data to reflect cooling associated with the later stages of crustal shortening (marked by folds) or the later extensional unroofing of the peninsula. This work demonstrates that an orogen can record multiple tectonic mode switches within several million years. These outcomes should be considered in studies of ancient orogens where analytical uncertainties associated with isotopic dating may mask short-lived mode switches.[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Author keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Analytical uncertainty,High-grade metamorphic rocks,Metamorphic core complex,Metamorphism,New Guinea,Systematic analysis,Tectono-thermal event,West Papua[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Indexed keywords” size=”size-sm” text_align=”text-left”][vc_column_text]Deformation,Geochronology,Metamorphism,New Guinea,West Papua,Zircon[/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”Funding details” size=”size-sm” text_align=”text-left”][vc_column_text][{‘$’: “This work was largely funded by a consortium of oil exploration companies that sponsored the Southeast Asia Research Group at Royal Holloway University of London where L.T.W. was based as a Postdoctoral Research Fellow prior to moving to the University of Wollongong at the beginning of 2017. Additional funding was provided to L.T.W. from the GeoQuEST Research Centre at the University of Wollongong. Niko Asia and Repsol are also thanked for sponsoring the 2013 field campaign of L.T.W. The University of Melbourne Thermochronology Laboratory receives infrastructure support under the AuScope program of the National Collaborative Research Infrastructure Strategy (NCRIS). We thank Manuel Pubellier, Nuretdin Kaymakci, and an anonymous reviewer for thoughtful reviews. The work presented here also benefited from discussions with John Decker, Phil Teas, Angus Fergusson, Farid Ferdian, Benjamin Jost, Max Webb, David Gold, Manuel Gonzalez-Quijano, and Carlos Diaz. We thank Martin Rittner for the support when collecting LA-ICP-MS data as well as Kevin D’Souza for photographing several samples. The authors declare that there are no financial conflicts of interest associated with the publication of this work. Data supporting the conclusions can be obtained in the supporting information. Sample information has been catalogued using the international sample numbering scheme (ISDN) and managed within the SESAR database.”}, {‘$’: “This work was largely funded by a consortium of oil exploration companies that sponsored the Southeast Asia Research Group at Royal Holloway University of London where L.T.W. was based as a Postdoctoral Research Fellow prior to moving to the University of Wollongong at the beginning of 2017. Additional funding was provided to L.T. W. from the GeoQuEST Research Centre at the University of Wollongong. Niko Asia and Repsol are also thanked for sponsoring the 2013 field campaign of L.T.W. The University of Melbourne Thermochronology Laboratory receives infrastructure support under the AuScope program of the National Collaborative Research Infrastructure Strategy (NCRIS). We thank Manuel Pubellier, Nuretdin Kaymakci, and an anonymous reviewer for thoughtful reviews. The work presented here also benefited from discussions with John Decker, Phil Teas, Angus Fergusson, Farid Ferdian, Benjamin Jost, Max Webb, David Gold, Manuel Gonzalez‐ Quijano, and Carlos Diaz. We thank Martin Rittner for the support when collecting LA‐ICP‐MS data as well as Kevin D’Souza for photographing sev eral samples. The authors declare that there are no financial conflicts of interest associated with the publication of this work. Data supporting the conclusions can be obtained in the supporting information. Sample information has been catalogued using the international sample numbering scheme (ISDN) and managed within the SESAR database.”}][/vc_column_text][vc_empty_space][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][vc_empty_space][megatron_heading title=”DOI” size=”size-sm” text_align=”text-left”][vc_column_text]https://doi.org/10.1029/2018TC005177[/vc_column_text][/vc_column_inner][vc_column_inner width=”1/4″][vc_column_text]Widget Plumx[/vc_column_text][/vc_column_inner][/vc_row_inner][/vc_column][/vc_row][vc_row][vc_column][vc_separator css=”.vc_custom_1624528584150{padding-top: 25px !important;padding-bottom: 25px !important;}”][/vc_column][/vc_row]