Large Igneous Provinces and their Plumbing Systems
Identification of large-volume, short-duration mafic magmatic events of intraplate affinity in both continental and oceanic settings on the Earth and other planets provides invaluable clues for understanding several vital geological issues of current concern. Of particular importance is understanding the assembly and dispersal of supercontinents through Earth's history, dramatic climate change events including mass extinctions, and processes that have produced a wide range of large igneous province (LIP)-related resources, such as Ni–Cu–PGE, Au, U, base metals and petroleum. This volume comprises 21 contributions on the latest developments and new information on LIPs and their plumbing systems and presents methodical studies on different components of LIP plumbing systems. These articles are especially helpful in understanding continental break-up events, regional domal uplift and a variety of metallogenic systems, as well as the temporal and spatial distribution of LIPs, their origin and their likely links to mantle plumes/superplumes.
Using a ‘speedy’ unspiked K–Ar methodology to investigate age patterns in giant mafic dyke swarms
Published:March 09, 2022
Alisson Lopes Oliveira, Maria Helena Bezerra Maia Hollanda, Roberto Siqueira, Antomat Avelino Macêdo Filho, 2022. "Using a ‘speedy’ unspiked K–Ar methodology to investigate age patterns in giant mafic dyke swarms", Large Igneous Provinces and their Plumbing Systems, Rajesh K. Srivastava, Richard E. Ernst, Kenneth L. Buchan, Michiel de Kock
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We present the results of a geochronological investigation that was conducted on mafic rocks (dolerites) that form two giant dyke swarms in NE Brazil, whose intrusion was correlated to the break-up of the West Gondwana supercontinent and the opening of the Atlantic Ocean. Despite their impressive dimensions, these swarms lack any geological information, which motivated us to develop a speedy, low-cost analytical protocol, modified from the Cassignol unspiked K–Ar technique, to define age patterns. The results were interpreted in light of basic statistical treatments and, although some limitations were mostly related to grain-size heterogeneities, they successfully matched other 40K-based ages (conventional K–Ar and 40Ar/39Ar) reported in the literature and showed that the dyke swarms share two main age intervals of rock formation identified as the Early Cretaceous and Late Jurassic.