Aspects of Franklinian shelf, slope and trough evolution and stratigraphy in North Greenland

Abstract

The Early Palaeozoic Franklinian basin of North Greenland was initiated in early Cambrian times with the onset of siliciclastic and mixed carbonate shelf deposition on a substratum of Proterozoic sediments and Precambrian crystalline basement. The basin rapidly differentiated into shelf, slope, and trough environments. The boundary between these major depositional regimes follows major roughly east-west trending lineaments. The inner-outer shelf transition fluetuated widely in position and was controlled by the interplay between sea-level changes and periodic northwards downwarping. In Ordovician-Silurian times the margin of the carbonate platform migrated northwards to coincide with the shelf-slope break and had a steep scarp configuration with an abrupt transition to the shales and turbidites of the deep-water basin. In this paper we pay special attention to the initial basin sequence (Skagen Group), the collapsed and broken platform carbonates of the Lower Cambrian Portfjeld Formation, the Middle - Late Cambrian inner-outer shelf transition and to the nature of the Silurian platform margin scarp.