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“Large Igneous Provinces (LIPs)”: Definition, recommended terminology, and a hierarchical classification

Hetu C. Sheth
Department of Earth Sciences, Indian Institute of Technology (IIT) Bombay, Powai,
Mumbai 400 076 India,

Correct and appropriate terminology is important for the so-called Large Igneous Provinces (LIPs). The term LIP is widely applied to large basaltic provinces such as the Deccan, and the term Silicic Large Igneous Province (SLIP) to volcanic provinces of dominantly felsic composition, such as the Whitsunday. Neither term has been applied to the large granitic batholiths of the world (e.g., Andes) to which both are perfectly applicable. LIP has also not been applied to broad areas of contemporaneous magmatism (e.g., Mongolia) and sizeable layered mafic intrusions (e.g., Bushveld) which are also true “large igneous provinces”. I suggest that the term “LIP” is used only in its broad sense and that an “LIP” should have an area of 50,000 km2 as a minimum size limit. I will present a simple hierarchical classification of LIPs that is independent of composition, tectonic setting, or emplacement mechanism. I suggest that provinces such as the Deccan and Whitsunday should be called Large Volcanic Provinces (LVPs), and large mafic intrusions, dyke swarms, and other intrusive provinces should be called Large Plutonic Provinces (LPPs). LVPs and LPPs together cover all large igneous provinces (LIPs), having felsic to ultramafic compositions, of sub-alkalic and alkalic lineages, emplaced in continental and oceanic settings. LVPs are subdivided here into four groups: (i) the dominantly/wholly mafic Large Basaltic Provinces (LBPs) (e.g., Deccan, Ontong Java); (ii) the dominantly felsic Large Rhyolitic Provinces (LRPs) (e.g., Whitsunday, Sierra Madre Occidental); (iii) the dominantly andesitic Large Andesitic Provinces (LAPs) (e.g., Andes, Indonesia, Cascades), and (iv) the bimodal Large Basaltic-Rhyolitic Provinces (LBRPs) (e.g., Snake River-High Lava Plains). The intrusive equivalent of LRPs are the Large Granitic Provinces (LGPs) (e.g., the Andean batholiths), but a corresponding term for intrusive equivalents of LBPs is not necessary or warranted. The largest LBP, and LIP, is of course the ocean floor. It is hoped that the proposed classification and nomenclature of LIPs will result in more accurate use of terminology and hence understanding of the wide variety of large igneous provinces.