Silicic magmatism associated with Late Cretaceous rifting in the Arctic Basin—petrogenesis of the Kap Kane sequence, the Kap Washington Group volcanics, North Greenland

Origin of Bentonites and Detrital Zircons of the Paleocene Basilika Formation, Svalbard

“…The REE patterns of some of the Basilika Formation bentonites as well as Lawson-ash 1 broadly resemble those of the evolved members of the Kap Washington Group on North Greenland as well as volcanic detritus in the Cape Back Basin near Nares Strait on Ellesmere Island (Estrada et al, 2010;Thorarinsson et al, 2011a). The Kap Washington Group comprises a 5000 m thick suite of bimodal, basaltic to rhyolitic rocks, which was emplaced between 71 and 61 Ma (Brown et al, 1987;Estrada et al, 2001;Tegner et al, 2011;Thorarinsson et al, 2011a,b).…”

“…The REE patterns of the second group actually look similar to pelitic sediments, but the positive ε Nd (t) value of sample TH 145 and the small positive Eu anomalies of the FTS 78 samples point to a volcanic origin. The small positive Eu anomalies point to a source in North Greenland or northeastern Ellesmere Island (Thorarinsson et al, 2011a;Estrada, 2015). The REE patterns of the FTS 35−36 samples (Erdmannflya) are similar to those of the geochemically evolved Bjørndalen bentonites H1 and H4, but are steeper.…”

“…The Kap Washington Group comprises a 5000 m thick suite of bimodal, basaltic to rhyolitic rocks, which was emplaced between 71 and 61 Ma (Brown et al, 1987;Estrada et al, 2001;Tegner et al, 2011;Thorarinsson et al, 2011a,b). The evolved phase of the Kap Washington Group was associated with explosive volcanism producing tuffs, ignimbrites, and pyroclastic sandstones (Brown et al, 1987;Thorarinsson et al, 2011a) and may potentially have sourced part of the bentonites on Svalbard and Ellesmere Island. In this case, the time of deposition of Lawson-ash 1 would need to coincide with the last volcanic activity on northern Greenland, which can be reconciled only if the maximum errors of age determinations are considered (Reinhardt et al, 2013).…”

“…Moreover, the initial εNd(t) values of Lawson-ash 1 [εNd(60) = 2.9] exclude a provenance from the evolved phase of the Kap Washington Group [εNd (70) < 1]. Similarly, the εNd(60) values of the Basilika Formation bentonites (0.3−1.6) are higher than or within the upper range of the most positive εNd(t) values observed in evolved rocks of the Kap Washington Group (Estrada and Henjes-Kunst, 2004;Thorarinsson et al, 2011a).…”

“…The HALIP is manifested in Cretaceous flood basalts, dykes and sills on eastern Svalbard and the adjacent subseafloor (Maher, 2001;Minakov et al, 2012;Corfu et al, 2013), Franz Josef Land, Ellesmere Island, and other islands in the Canadian Arctic (Embry and Osadetz, 1988;Estrada andHenjes-Kunst, 2004, 2013;Corfu et al, 2013;Jowitt et al, 2014), as well as Late Cretaceous to Paleocene dykes and extrusive magmatism on northern Greenland and the Canadian Arctic islands (Figure 1; e.g., Estrada et al, 2001;Kontak et al, 2001;Tegner et al, 2011;Thorarinsson et al, 2011a).…”