Provenance of basinal sandstones in the Upper Jurassic Hareelv Formation, Jameson Land Basin, East Greenland

Mette Olivarius,Nynke Keulen,Christian Knudsen,Morten Bjerager,Thomas F Kokfelt

doi:10.34194/geusb.v42.4317

Abstract

Zircon U–Pb geochronology and heavy mineral CCSEM analysis were used to interpret the provenance of Oxfordian–Volgian sandstones of the Hareelv Formation in East Greenland. Six samples were collected from the Blokelv-1 core drilled in southern Jameson Land, and the zircon age distributions and heavy-mineral assemblages are quite uniform. The samples contain a wide spectrum of Archaean to Palaeozoic zircon ages with peak ages at 2.71, 2.49, 1.95, 1.65, 1.49, 1.37, 1.10 and 0.43 Ga when combining all data. The heavy-mineral compositions show derivation from felsic source rocks, some of which were metamorphic. The results reveal that the sediment was derived from the Caledonides, and it is plausible that some or all of the material has experienced several cycles of sedimentation. Devonian and Carboniferous sediments preserved north of the area have zircon age distributions that correspond to those from the Hareelv Formation, and such rocks may have been reworked into the Jameson Land Basin. The provenance signature describes both the gravity-flow sandstones of the Hareelv Formation and the delta-edge sands that are inferred to have fed them. Lithological and provenance contrasts between the sandstones of the Sjællandselv Member and those of the Katedralen Member indicate a shorter transport distance, source to sink, suggestive of proximal topographic rejuvenation in the Volgian.

Highlights

Zircon U–Pb geochronology and heavy mineral computercontrolled scanning electron microscopy (CCSEM) analysis were used to interpret the provenance of Oxfordian–Volgian sandstones of the Hareelv Formation in East Greenland
The East Greenland Caledonides, which form the basement for the Mesozoic succession, comprise a complex series of Archaean to Palaeozoic lithologies (Higgins & Leslie 2008), and the post-Caledonian sedimentary successions preserved along the East and North-East Greenland coast (Fig. 1) are expected to contain a wide range of zircon age populations
The present study employs zircon geochronology and heavy-mineral analysis to characterise the Upper Jurassic sandstones of the Hareelv Formation in the Blokelv-1 core and to identify the source areas of these sandstones

Summary

Results

The zircon U–Pb age data can be found in the online supplementary material. The age data are displayed using kernel-density estimation (Fig. 4) and cumulative age distribution (Fig. 5). Pronounced peak ages are present within each of the 1.8–1.6, 1.6–1.3 and 1.3–0.8 Ga age intervals, which cover 17–25, 14–22 and 18–34% of the measured ages, respectively (Table 1). The youngest age interval of 0.6–0.3 Ga is present in small proportions of 0–3% in the samples. The. MOL prov table 1 cumulative age distributions show that no significant difference exists between the six measured age distributions since the distance between the curves is small (Fig. 5). Kolmogorov-Smirnov (K-S) tests (Guynn & Gehrels 2010) were performed on the zircon age data to determine if the samples were derived from different sources by comparing the distance between the cumulative agedistribution curves (Fig. 5). The heavy-mineral content is largest in the uppermost sample (Table 3)

Discussion

2.67 Archaean–Palaeoproterozoic rocks

Conclusions