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 overturnin g and anomalous surface conditions. Widespread Cretaceous igneous activity in the High Arctic has recently been identified as a LIP. Exposed component s on Svalbard, Franz Josef Island, adjacent shelf areas, Axel Heiberg and E llesmere Islands, and perhaps North Greenland, cover several hundred thousa nd 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 up per part of thick, black shales punctuated by locally abrupt uplift, with o verlying coastal plain sandstones, (3) development of a regional, Late Cret aceous, low-angle unconformity associated with a second regression, and (4) a widespread Early Aptian transition from quartz arenites to lithic arenit es and feldspathic sandstones reflecting new northern volcanic source terra nes. The unconformity likely reflects LIP thermal doming with >1 km of eros ion. The sedimentologic record provides important insight into this LIP sin ce much of it is inaccessible or eroded. Analysis of published geochronolog y indicates magmatism within a 135-90 Ma window, with more detailed interpr etations being problematic. Two regressions suggest two pulses of igneous a ctivity (Barremian and Albian). Multiple pulses have been documented for ot her 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.