Manifestations of the Cretaceous High Arctic Large Igneous Province in Svalbard

Major Cretaceous Large Igneous Provinces (LIPs, e.g., Kerguelen and Ontong Java) show Aptian magmatic peaks and are linked to global mantle overturning and anomalous surface conditions. Widespread Cretaceous igneous activity in the High Arctic has recently been identified as a LIP. Exposed components on Svalbard, Franz Josef Island, adjacent shelf areas, Axel Heiberg and Ellesmere Islands, and perhaps North Greenland, cover several hundred thousand square kilometers and were peripheral to a LIP center at the Alpha Ridge. Manifestations of LIP development on Svalbard include (1) extensive sills, rare dikes, and extrusives in the east, (2) slow regression within the upper part of thick, black shales punctuated by locally abrupt uplift, with overlying coastal plain sandstones, (3) development of a regional, Late Cretaceous, low-angle unconformity associated with a second regression, and (4) a widespread Early Aptian transition from quartz arenites to lithic arenites and feldspathic sandstones reflecting new northern volcanic source terranes. The unconformity likely reflects LIP thermal doming with >1 km of erosion. The sedimentologic record provides important insight into this LIP since much of it is inaccessible or eroded. Analysis of published geochronology indicates magmatism within a 135-90 Ma window, with more detailed interpretations being problematic. Two regressions suggest two pulses of igneous activity (Barremian and Albian). Multiple pulses have been documented for other LIPs and may result from a deep and large plume. Present evidence that magmatism was coeval in Svalbard and Franz Josef Land is inconsistent with a hotspot track hypothesis and suggestive of a large initial plume head.