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Episodicity within a Mid-Cretaceous magmatic flare-up in West Antarctica; U-Pb ages of the Lassiter Coast intrusive suite, Antarctic Peninsula, and correlations along the Gondwana margin

Teal R. Riley, Alex Burton-Johnson, Michael J. Flowerdew and Martin J. Whitehouse
Episodicity within a Mid-Cretaceous magmatic flare-up in West Antarctica; U-Pb ages of the Lassiter Coast intrusive suite, Antarctic Peninsula, and correlations along the Gondwana margin
Geological Society of America Bulletin (January 2018) 130 (7-8): 1177-1196

Abstract

Long-lived continental margin arcs are characterized by episodes of large-volume magmatism (or flare-ups) that can persist for approximately 30 m.y. before steady-state arc conditions resume. Flare-up events are characterized by the emplacement of large-volume granodiorite-tonalite batholiths and sometimes associated rhyodacitic ignimbrites. One of the major flare-up events of the West Gondwana margin occurred during the mid-Cretaceous and was temporally and spatially associated with widespread deformation and Pacific plate reorganization. New U-Pb geochronology from the Lassiter Coast intrusive suite in the southern Antarctic Peninsula identifies a major magmatic event in the interval 130-102 Ma that was characterized by three distinct peaks in granitoid emplacement at 130-126 Ma, 118-113 Ma, and 108-102 Ma, with clear lulls in between. Mid-Cretaceous magmatism from elsewhere in West Antarctica, Patagonia, and New Zealand also featured marked episodicity during the mid-Cretaceous and recorded remarkable continuity along the West Gondwana margin. The three distinct magmatic events represent second-order episodicity relative to the primary episodicity that occurred on a cordillera scale and is a feature of the North and South American Pacific margin. Flare-up events require the development of a highly fusible, lower-crustal layer resulting from the continued underplating of hydrous mineralogies in the melt-fertile lower crust as a result of long-lived subduction. However, the actual trigger for melting is likely to result from external, potentially tectonic factors, e.g., rifting, plate reorganization, continental breakup, or mantle plumes.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 130
Serial Issue: 7-8
Title: Episodicity within a Mid-Cretaceous magmatic flare-up in West Antarctica; U-Pb ages of the Lassiter Coast intrusive suite, Antarctic Peninsula, and correlations along the Gondwana margin
Affiliation: British Antarctic Survey, Cambridge, United Kingdom
Pages: 1177-1196
Published: 20180122
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 87
Accession Number: 2018-032331
Categories: Igneous and metamorphic petrologyGeochronology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, geol. sketch maps
S77°00'00" - S63°00'00", W77°30'00" - W56°30'00"
S87°00'00" - S60°00'00", W165°00'00" - W40°00'00"
Secondary Affiliation: CASP, GBR, United KingdomSwedish Museum of Natural History, SWE, Sweden
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2022, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201817
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