tectonic context
A definition made entirely of size, rate and position — and deliberately silent about cause. Lithoen records the provinces and does not attribute them.
About: Siberian Traps · Deccan Traps
The USGS magmatic nickel model quotes Bryan and Ernst: magmatic provinces with areal extents greater than 0.1 million square kilometres, igneous volumes greater than 0.1 million cubic kilometres, maximum lifespans of about 50 million years, intraplate tectonic settings or geochemical affinities, and igneous pulses of short duration — about 1 to 5 million years — during which more than 75 percent of the total volume is emplaced.[1]
Every term in that definition is an extent, a volume, a duration or a position. None of it is a mechanism. A province meeting the definition is not thereby attributed to a mantle plume or to anything else.[1]
Continental flood basalts: the Deccan, Karoo, Siberian Traps and Columbia River provinces. A volcanic rifted margin: the North Atlantic Igneous Province. An oceanic plateau: Ontong Java. Ocean-basin flood basalts: the Caribbean. Their plumbing systems — dykes, sills and layered intrusions — are part of the provinces rather than separate from them.[1]
Lithoen holds nothing further about most of these. The records for Karoo, Columbia River, the North Atlantic province and Ontong Java exist to hold a name in its correct class, and say so. No extent, no dates, no volume, and no origin — because no retrieved source supplies any.[1]
The Noril’sk intrusions, which host the largest known magmatic nickel-copper-PGE deposits, belong to the plumbing system of the Siberian Traps. Since the definition includes dykes, sills and layered intrusions within a province, the deposit and the flood basalt are parts of one thing.[1]
Every large igneous province has a plumbing system. Almost none of it hosts a deposit of that kind, and the corpus records that alongside the association rather than after it.[1,2]
Often said
“Large igneous provinces are produced by mantle plumes.”
What the evidence supports
The definition Lithoen cites is stated entirely in terms of extent, volume, duration and setting, and says nothing about cause. Whether plumes exist as described is separately recorded in this corpus as contested.
Supporting records: lip-observed-not-explained · lip-definition
Bracketed references link to the structured entity records whose claims support each paragraph. Last updated 2026-09-07.