Facies model for a coarse‐grained, tide‐influenced delta: Gule Horn Formation (Early Jurassic), Jameson Land, Greenland

Christian Haug Eide,Bjørn Terje Oftedal,John A Howell,Gijs A Henstra,Simon J Buckley,Allard W Martinius

doi:10.1111/sed.12270

Christian Haug Eide, Bjørn Terje Oftedal + Show 4 more

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https://doi.org/10.1111/sed.12270

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Abstract

AbstractTide‐dominated deltas have an inherently complex distribution of heterogeneities on several different scales and are less well‐understood than their wave‐dominated and river‐dominated counterparts. Depositional models of these environments are based on a small set of ancient examples and are, therefore, immature. The Early Jurassic Gule Horn Formation is particularly well‐exposed in extensive sea cliffs from which a 32 km long, 250 m high virtual outcrop model has been acquired using helicopter‐mounted light detection and ranging (LiDAR). This dataset, combined with a set of sedimentological logs, facilitates interpretation and measurement of depositional elements and tracing of stratigraphic surfaces over seismic‐scale distances. The aim of this article is to use this dataset to increase the understanding of depositional elements and lithologies in proximal, unconfined, tide‐dominated deltas from the delta plain to prodelta. Deposition occurred in a structurally controlled embayment, and immature sediments indicate proximity to the sediment source. The succession is tide dominated but contains evidence for strong fluvial influence and minor wave influence. Wave influence is more pronounced in transgressive intervals. Nine architectural elements have been identified, and their internal architecture and stratigraphical distribution has been investigated. The distal parts comprise prodelta, delta front and unconfined tidal bar deposits. The medial part is characterized by relatively narrow, amalgamated channel fills with fluid mud‐rich bases and sandier deposits upward, interpreted as distributary channels filled by tidal bars deposited near the turbidity maximum. The proximal parts of the studied system are dominated by sandy distributary channel and heterolithic tidal‐flat deposits. The sandbodies of the proximal tidal channels are several kilometres wide and wider than exposures in all cases. Parasequence boundaries are easily defined in the prodelta to delta‐front environments, but are difficult to trace into the more proximal deposits. This article illustrates the proximal to distal organization of facies in unconfined tide‐dominated deltas and shows how such environments react to relative sea‐level rise.

Highlights

Tidal depositional systems are characterized by cyclical and rapid variations in flow velocity and, have inherently complex heterogeneities and incision on several different scales (e.g. Willis, 2005; Dalrymple & Choi, 2007; Martinius & Van den Berg, 2011)
Transgressive tidedominated systems that occur as estuaries are relatively well-studied and have robust facies models (Dalrymple et al, 1992), whereas progradational tidal delta systems have received less attention in the literature
The aims of this study are fourfold: (i) to describe the deposits of the Gule Horn Formation in the study area; (ii) to propose a facies model for this succession which may be applicable to similar deposits elsewhere; (iii) to collect architectural data on the individual depositional elements within the tide-dominated delta succession; and (iv) to interpret how the system evolved through time under external and internal forcing factors

Summary

Introduction

Tidal depositional systems are characterized by cyclical and rapid variations in flow velocity and, have inherently complex heterogeneities and incision on several different scales (e.g. Willis, 2005; Dalrymple & Choi, 2007; Martinius & Van den Berg, 2011). Transgressive tidedominated systems that occur as estuaries are relatively well-studied and have robust facies models (Dalrymple et al, 1992), whereas progradational tidal delta systems have received less attention in the literature Depositional models of such environments are based on a small, but growing, set of studied ancient The limited number of studies has led to a lack of data on geometries of depositional elements in tidal systems. These two factors present great uncertainties in forecasting hydrocarbon reservoir development of ancient deposits of tidal systems (Brandsæter et al, 2005; Martinius et al, 2005; Filak et al, 2012)

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