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Large igneous provinces and silicic large igneous provinces; progress in our understanding over the last 25 years

Scott E. Bryan and Luca Ferrari
Large igneous provinces and silicic large igneous provinces; progress in our understanding over the last 25 years
Geological Society of America Bulletin (April 2013) 125 (7-8): 1053-1078

Abstract

Large igneous provinces are exceptional intraplate igneous events throughout Earth's history. Their significance and potential global impact are related to the total volume of magma intruded and released during these geologically brief events (peak eruptions are often within 1-5 m.y. in duration) where millions to tens of millions of cubic kilometers of magma are produced. In some cases, at least 1% of Earth's surface has been directly covered in volcanic rock, being equivalent to the size of small continents with comparable crustal thicknesses. Large igneous provinces thus represent important, albeit episodic, periods of new crust addition. However, most magmatism is basaltic, so that contributions to crustal growth will not always be picked up in zircon geochronology studies, which better trace major episodes of extension-related silicic magmatism and the silicic large igneous provinces. Much headway has been made in our understanding of these anomalous igneous events over the past 25 yr, driving many new ideas and models. (1) The global spatial and temporal distribution of large igneous provinces has a long-term average of one event approximately every 20 m.y., but there is a clear clustering of events at times of supercontinent breakup, and they are thus an integral part of the Wilson cycle and are becoming an increasingly important tool in reconnecting dispersed continental fragments. (2) Their compositional diversity in part reflects their crustal setting, such as ocean basins and continental interiors and margins, where, in the latter setting, large igneous province magmatism can be dominated by silicic products. (3) Mineral and energy resources, with major platinum group elements (PGEs) and precious metal resources, are hosted in these provinces, as well as magmatism impacting on the hydrocarbon potential of volcanic basins and rifted margins through enhancing source-rock maturation, providing fluid migration pathways, and initiating trap formation. (4) Biospheric, hydrospheric, and atmospheric impacts of large igneous provinces are now widely regarded as key trigger mechanisms for mass extinctions, although the exact kill mechanism(s) are still being resolved. (5) Their role in mantle geodynamics and thermal evolution of Earth as large igneous provinces potentially record the transport of material from the lower mantle or core-mantle boundary to the Earth's surface and are a fundamental component in whole mantle convection models. (6) Recognition of large igneous provinces on the inner planets, with their planetary antiquity and lack of plate tectonics and erosional processes, means that the very earliest record of large igneous province events during planetary evolution may be better preserved there than on Earth.


ISSN: 0016-7606
EISSN: 1943-2674
Coden: BUGMAF
Serial Title: Geological Society of America Bulletin
Serial Volume: 125
Serial Issue: 7-8
Title: Large igneous provinces and silicic large igneous provinces; progress in our understanding over the last 25 years
Affiliation: Queensland University of Technology, School of Earth, Environmental and Biological Sciences, Brisbane, Queensl., Australia
Pages: 1053-1078
Published: 20130425
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 300
Accession Number: 2013-041405
Categories: Igneous and metamorphic petrology
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. geol. sketch maps
N22°45'00" - N32°00'00", W115°00'00" - W106°00'00"
N22°00'00" - N31°15'00", W112°00'00" - W104°19'60"
Secondary Affiliation: Universidad Nacional Autonoma de Mexico, MEX, Mexico
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, 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: 201326
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