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Article: Paleomagnetic data support Early Permian age for the Abor Volcanics in the lower Siang Valley, NE India: Significance for Gondwana-related break-up models

TitlePaleomagnetic data support Early Permian age for the Abor Volcanics in the lower Siang Valley, NE India: Significance for Gondwana-related break-up models
Authors
KeywordsArtinskian
Bhote Khosi Basalts
Cimmerian terrane
Eastern Syntaxis
Gondwana
Kiaman
Nar Tsum Spilites
Panjal Traps
Permian
Siang Window
Issue Date2012
PublisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/jseaes
Citation
Journal Of Asian Earth Sciences, 2012, v. 50, p. 105-115 How to Cite?
AbstractConfusion exists as to the age of the Abor Volcanics of NE India. Some consider the unit to have been emplaced in the Early Permian, others the Early Eocene, a difference of ∼230 million years. The divergence in opinion is significant because fundamentally different models explaining the geotectonic evolution of India depend on the age designation of the unit. Paleomagnetic data reported here from several exposures in the type locality of the formation in the lower Siang Valley indicate that steep dipping primary magnetizations (mean = 72.7 ± 6.2°, equating to a paleo-latitude of 58.1°) are recorded in the formation. These are only consistent with the unit being of Permian age, possibly Artinskian based on a magnetostratigraphic argument. Plate tectonic models for this time consistently show the NE corner of the sub-continent >50°S; in the Early Eocene it was just north of the equator, which would have resulted in the unit recording shallow directions. The mean declination is counter-clockwise rotated by ∼94°, around half of which can be related to the motion of the Indian block; the remainder is likely due local Himalayan-age thrusting in the Eastern Syntaxis. Several workers have correlated the Abor Volcanics with broadly coeval mafic volcanic suites in Oman, NE Pakistan-NW India and southern Tibet-Nepal, which developed in response to the Cimmerian block peeling-off eastern Gondwana in the Early-Middle Permian, but we believe there are problems with this model. Instead, we suggest that the Abor basalts relate to India-Antarctica/India-Australia extension that was happening at about the same time. Such an explanation best accommodates the relevant stratigraphical and structural data (present-day position within the Himalayan thrust stack), as well as the plate tectonic model for Permian eastern Gondwana. © 2012 Elsevier Ltd.
Persistent Identifierhttp://hdl.handle.net/10722/146388
ISSN
2015 Impact Factor: 2.647
2015 SCImago Journal Rankings: 1.393
ISI Accession Number ID
Funding AgencyGrant Number
CERG - HKU7002/05
HKU7001/10
CERG - HKU7001/07
Funding Information:

Research Grants to JRA (CERG - HKU7002/05, HKU7001/10) and JCA (CERG - HKU7001/07) supported the fieldwork and laboratory studies. Muraleedharan Nair of the Indian Consular Office in Hong Kong provided valuable assistance and advice. Oken Tayeng (Abor Country Travels and Expeditions) and Nino Dai (Donyi Hanggo Adventure Tours and Travels) are thanked for organizing our field-trips. Rob Van der Voo (University of Michigan) kindly shared information. Ravikant Vadlamani (Indian Institute of Science Education and Research at Kolkata) assisted with a number of questions regarding the Upper Paleozoic rocks of northern India.

References

 

DC FieldValueLanguage
dc.contributor.authorAli, JRen_HK
dc.contributor.authorAitchison, JCen_HK
dc.contributor.authorChik, SYSen_HK
dc.contributor.authorBaxter, ATen_HK
dc.contributor.authorBryan, SEen_HK
dc.date.accessioned2012-04-24T07:50:54Z-
dc.date.available2012-04-24T07:50:54Z-
dc.date.issued2012en_HK
dc.identifier.citationJournal Of Asian Earth Sciences, 2012, v. 50, p. 105-115en_HK
dc.identifier.issn1367-9120en_HK
dc.identifier.urihttp://hdl.handle.net/10722/146388-
dc.description.abstractConfusion exists as to the age of the Abor Volcanics of NE India. Some consider the unit to have been emplaced in the Early Permian, others the Early Eocene, a difference of ∼230 million years. The divergence in opinion is significant because fundamentally different models explaining the geotectonic evolution of India depend on the age designation of the unit. Paleomagnetic data reported here from several exposures in the type locality of the formation in the lower Siang Valley indicate that steep dipping primary magnetizations (mean = 72.7 ± 6.2°, equating to a paleo-latitude of 58.1°) are recorded in the formation. These are only consistent with the unit being of Permian age, possibly Artinskian based on a magnetostratigraphic argument. Plate tectonic models for this time consistently show the NE corner of the sub-continent >50°S; in the Early Eocene it was just north of the equator, which would have resulted in the unit recording shallow directions. The mean declination is counter-clockwise rotated by ∼94°, around half of which can be related to the motion of the Indian block; the remainder is likely due local Himalayan-age thrusting in the Eastern Syntaxis. Several workers have correlated the Abor Volcanics with broadly coeval mafic volcanic suites in Oman, NE Pakistan-NW India and southern Tibet-Nepal, which developed in response to the Cimmerian block peeling-off eastern Gondwana in the Early-Middle Permian, but we believe there are problems with this model. Instead, we suggest that the Abor basalts relate to India-Antarctica/India-Australia extension that was happening at about the same time. Such an explanation best accommodates the relevant stratigraphical and structural data (present-day position within the Himalayan thrust stack), as well as the plate tectonic model for Permian eastern Gondwana. © 2012 Elsevier Ltd.en_HK
dc.languageengen_US
dc.publisherPergamon. The Journal's web site is located at http://www.elsevier.com/locate/jseaesen_HK
dc.relation.ispartofJournal of Asian Earth Sciencesen_HK
dc.subjectArtinskianen_HK
dc.subjectBhote Khosi Basaltsen_HK
dc.subjectCimmerian terraneen_HK
dc.subjectEastern Syntaxisen_HK
dc.subjectGondwanaen_HK
dc.subjectKiamanen_HK
dc.subjectNar Tsum Spilitesen_HK
dc.subjectPanjal Trapsen_HK
dc.subjectPermianen_HK
dc.subjectSiang Windowen_HK
dc.subject.meshEocene-
dc.subject.meshGondwana-
dc.subject.meshMagnetization-
dc.subject.meshMagnetostratigraphy-
dc.subject.meshPaleolatitude-
dc.titlePaleomagnetic data support Early Permian age for the Abor Volcanics in the lower Siang Valley, NE India: Significance for Gondwana-related break-up modelsen_HK
dc.typeArticleen_HK
dc.identifier.emailAli, JR: jrali@hku.hken_HK
dc.identifier.emailAitchison, JC: jona@hku.hken_HK
dc.identifier.authorityAli, JR=rp00659en_HK
dc.identifier.authorityAitchison, JC=rp00658en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.jseaes.2012.01.007en_HK
dc.identifier.scopuseid_2-s2.0-84859005201en_HK
dc.identifier.hkuros199130en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-84859005201&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume50en_HK
dc.identifier.spage105en_HK
dc.identifier.epage115en_HK
dc.identifier.isiWOS:000303431900011-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridAli, JR=7102266465en_HK
dc.identifier.scopusauthoridAitchison, JC=7102533858en_HK
dc.identifier.scopusauthoridChik, SYS=55058900100en_HK
dc.identifier.scopusauthoridBaxter, AT=35069077600en_HK
dc.identifier.scopusauthoridBryan, SE=7103134872en_HK

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