The sedimentology and depositional environments of the Bastians Dal and Muslingebjerg formations: evidence for the earliest phases of Jurassic rifting in North-East Greenland

The aim of this study is to elucidate the character of the earliest phases of Jurassic rifting in North-East Greenland. To achieve this, detailed sedimentological analysis and geological mapping were undertaken on the outcrops of central Kuhn Ø (74°53’55’’N,20°20’56”W). In this region the basement is overlain by the fluvial Bastians Dal Formation (Middle Jurassic) which is, in turn, overlain by the coal-bearing Muslingebjerg Formation. A maximum thickness of 140 m is calculated for the Bastians Dal Formation and mapping of stratal geometries demonstrates thinning to both the north and south, confirming that these deposits infill a palaeovalley. Predominantly south-westward palaeocurrent orientations are observed and likely reflect the orientation of the palaeovalley (NE–SW). The overlying Muslingebjerg Formation displays significant lateral variations in thickness as well as facies, thickening from a 5-m-thick coal seam in the north to 50 m in the south. Southern outcrops include two intervals of fine-grained sandstones displaying low-angle and trough cross-bedding some of which contain suggestions of tidal bundling. The arrangement of facies suggests that coal formation occurred in both fluvial- and shallow-marine (tidal?) environments. Coals are similar to those described elsewhere from the Muslingebjerg Formation and display subtle differences consistent with variable degrees of marine influence. Mapping demonstrates the presence of an NE–SW-oriented bounding fault in the south of the region into which the Muslingebjerg Formation thickens. This likely also controlled the orientation of the underlying NE–SW-aligned palaeovalley and is oblique to the proposed overall N–S orientation of faulting related to rifting through the Mid to Late Jurassic. Instead, these alignments resemble those that define pre-Jurassic phases of rifting and may therefore indicate a transitional phase of tectonism. Faulting on a similar alignment can be traced SW, cutting Lindeman Fjord and following the valleys east of the A. P. Olsen Land plateau

Petroleum geochemistry of the deepened Lopra-1/1A re-entry well, Faroe Islands

The Lopra-1/1A re-entry well was drilled as a stratigraphic test with no immediate exploration objectives. Hence, petroleum geochemical studies were of limited extent, and restricted to non-destructive analyses. The presence of natural petroleum hydrocarbons could not be confirmed with certainty, but hydrocarbons extracted from the hydrochloric acid solute of a calcite vug present in RSWC #1 (3543 m), may represent indigenous petroleum since hydrocarbon-bearing fluid inclusions have been reported from the same sample. These hydrocarbons show some similarities to petroleum generated from the Upper Jurassic – Lower Cretaceous Kimmeridge Clay type source rocks present in surrounding areas. Except for this sample, the results generally show the presence of a variety of contaminants of different origins such as ‘naturally greasy fingers’ (squalene and cholesterol), cosmetics such as chap stick or hand lotion (e.g. esters such as butyl-stearate, stearyl-palmitate, vitamin A), plasticisers (phthalates), diesel oil and ‘pipe dope’

Six years of petroleum geological activities in North-East Greenland (2008–2013): projects and a view of the future

The deadline for applications to the first licence round for petroleum exploration offshore North-East Greenland was 15 December 2012. The round was restricted, allowing only members of the KANUMAS consortium to be operators (BP, Chevron, Exxon, JOGMEG, Shell and Statoil). Nunaoil is also part of KANUMAS, but it is a carried, non-operator partner. An ordinary licensing round followed shortly after with a deadline on 15 October 2013

Age of oils in West Greenland: was there a Mesozoic seaway between Greenland and Canada?

For many years the existence of an oil-prone source rock off West Greenland was challenged by industry. But since 1992 when active oil seeps were found onshore West Greenland on the Nuussuaq peninsula (Fig. 1; Christiansen et al. 1996; Bojesen-Koefoed et al. 1999), the question has changed focus to the age, distribution and potential of the source rock. Five different oils – each with their own characteristics – have been reported by the Geological Survey of Denmark and Greenland (GEUS). One of these, a typical marine shalederived oil with a possible regional distribution, is known as the Itilli oil. Geochemical analysis suggests that it may have been generated from Cenomanian–Turonian age marine shales, equivalent to prolific source rocks known from Ellesmere Island, Nunavut, Canada. Three of the other oils were generated from deltaic source rocks of Albian, Campanian and Paleocene ages, while one is of unknown origin (Bojesen-Koefoed et al. 1999). The presence of a regional marine source rock is important to petroleum exploration; GEUS has therefore investigated the possible existence of Mesozoic, in particular Cenomanian–Turonian, petroleum source rocks in West Greenland offshore areas. Since sediments older than the Santonian are not known from any of the six wells drilled offshore West Greenland (Fig. 1), assessment of oil-prone source rocks in older sedimentary successions must rely on circumstantial evidence offered by oil chemistry data and analogy studies. Petroleum in quantities amenable to chemical analysis has so far not been recovered from offshore. However, oilbearing fluid inclusions are known from the Ikermiut-1 well (unpublished data 2001, Phillips Petroleum and GEUS), a gas-kick was recorded during drilling of the Kangâmiut-1 well (Bate 1997), and seismic data indicate hydrocarbons in many areas (cross-cutting reflectors, bright spots, smearing of seismic). Petroleum exploration offshore West Greenland suffered for many years under the misconception that oceanic crust covered vast areas, rendering the region unattractive. However, the presence of thick sedimentary successions and rotated fault blocks in Cretaceous basins have been demonstrated to be present in areas previously believed to be underlain by Cretaceous–Tertiary oceanic crust (cf. Chalmers & Pulvertaft 2001). New high-quality seismic data, acquired by the seismic company TGS-NOPEC over recent years, combined with gravimetric data, have further demonstrated the presence of deep basins containing thick sedimentary successions in other areas (e.g. Christiansen et al. 2002). Despite the progress made over the past few years, the geological evolution of the Davis Strait region in general remains poorly understood, but new data on oil chemistry may shed some light on the history of this region

The Rødryggen-1 and Brorson Halvø-1 fully cored boreholes (Upper Jurassic – Lower Cretaceous), Wollaston Forland, North-East Greenland – an introduction

Two fully cored boreholes, the Rødryggen-1 and the Brorson Halvø-1, were drilled in Wollaston Forland, North-East Greenland, in 2009 and 2010, respectively. The objective was to test the stratigraphic development of the Upper Jurassic – Lower Cretaceous mud-dominated succession in two different settings within the same fault block of a developing half-graben: centrally (Rødryggen-1 borehole) and near the uplifted crest of the rotating fault block (Brorson Halvø-1 borehole). The drilled deposits are equivalent to the principal petroleum source-rock sequence of the petroliferous basins of North-West Europe, Siberia, and basins off eastern Canada and provide a new record of an important phase of marine deoxygenation in the proto-North Atlantic region

Organic geochemistry of an Upper Jurassic – Lower Cretaceous mudstone succession in a narrow graben setting, Wollaston Forland Basin, North-East Greenland

The Oxfordian–Ryazanian was a period of widespread deposition of marine organic-rich mudstones in basins formed during the early phases of the rifting that heralded the formation of the present-day North Atlantic. Occasionally, uninterrupted deposition prevailed for 20 million years or more. Today, mudstones of this time interval are found on the shelves bordering the North Atlantic and adjacent areas from Siberia to the Netherlands. Here, we report data on two fully cored boreholes from Wollaston Forland (North-East Greenland, approx. 74° N), which represent an uninterrupted succession from the upper Kimmeridgian to the Hauterivian. The boreholes record basin development at two different positions within an evolving halfgraben, located at the margin of the main rift, and thus partially detached from it. Although the overall depositional environment remained an oxygen-restricted deep-shelf setting, rifting-related changes can be followed through the succession. The Kimmeridgian was a period of eustatic highstand and records the incipient rifting with a transgressive trend straddling the transition to the lower Volgian by a gradual change from deposits with high levels of total organic carbon (TOC) and kerogen rich in allochthonous organic matter to deposits with lower TOC and a higher proportion of autochthonous organic matter. This is followed by a slight regressive trend with lower TOC and increased proportions of allochthonous organic matter until rifting culminated in the middle Volgian–Ryazanian, indicated by increasing autochthonous organic matter and higher TOC, which prevailed until basin ventilation occurred towards the end of the Ryazanian. The properties of the reactive kerogen fraction remained rather stable irrespective of TOC, underlining the effect of terrigenous matter input for TOC. These variations are also captured by biological markers and stable carbon isotopes. The deposits are very similar to equivalent successions elsewhere in the proto-North Atlantic region, albeit the proportion of terrigenous kerogen is greater

Petroleum geology of the Upper Jurassic – Lower Cretaceous of East and North-East Greenland: Blokelv-1 borehole, Jameson Land Basin: Colophon, contents, preface

The exposed Jurassic succession in East and North-East Greenland has long been presented as an analogue for equivalent deeply buried strata on the Norwegian conjugate shelf and offshore North-East Greenland. In particular, the Upper Jurassic marine mudstone succession is often ascribed source-rock potential as proven from coeval rocks on the Northwest European margin. Previous outcrop investigations have not convincingly confirmed this potential, however, and three boreholes were drilled between 2008 and 2010 to provide full coverage of the Upper Jurassic – Lower Cretaceous petroleum source-rock succession in eastern Greenland. The Blokelv-1 borehole was drilled in 2008 in central Jameson Land to investigate the Middle Oxfordian – Lower Volgian Hareelv Formation, representing the lowermost part of the composite source-rock succession. The common aim of the collection of eight scientific papers in this bulletin, introduced by an account of the technical and logistic challenges of the drilling operation, is to document the significance of the Hareelv Formation in a petroleum geological context. Papers on the biostratigraphy, sedimentology, provenance and diagenesis establish the framework and geological history of the succession while companion papers on the source-rock potential, burial and exhumation history and igneous intrusive activity in the region contribute to an improved understanding of the petroleum geology of the Jameson Land Basin

Colophon, contents, preface

This bulletin presents a series of nine papers dealing with the succession of Upper Jurassic – Lower Cretaceous sedimentary rocks penetrated by the fully cored Blokelv-1 borehole, drilled in western Jameson Land, central East Greenland in August 2008. The borehole was drilled as the first of three boreholes that in combination were designed to provide full coverage of the Upper Jurassic – Lower Cretaceous petroleum source-rock succession in eastern Greenland. The remaining two boreholes, Rødryggen-1 and Brorson Halvø-1, were drilled on Wollaston Forland in 2009 and 2010, respectively, and the results from these boreholes will be published in a companion volume. The objectives of the drilling campaign were fulfilled, demonstrating that continuous sedimentation of oil-prone petroleum source rocks took place in eastern Greenland over a period of c. 13 million years from the Oxfordian to the Ryazanian, with the Blokelv-1 succession representing the older, Oxfordian–Volgian part of this interval. The drilling campaign was carried out as one of a number of projects within the framework of a multi-client collaborative programme between GEUS and a long list of petroleum companies entitled Petroleum Geological Studies, Services and Data in East and Northeast Greenland. This collaboration was initiated in 2007 and is ongoing at the time of writing with more than 20 participant companies, a subset of which sponsored the studies presented herein; for contractual reasons, these companies cannot be named. The GEUS–industry collaboration was initiated in recognition of the need for new and better data on many aspects of the petroleum geology of eastern Greenland prior to an anticipated licensing round of offshore North-East Greenland. The Circum-Arctic Resource Appraisal (CARA), undertaken by the United States Geological Survey (USGS), also played an important role in defining the priorities of the collaborative agreement by directing attention towards specific subjects in need of investigation. Licensing rounds in 2012 and 2013 resulted in the award of five licences. Based on the results of these activities in eastern Greenland, a large number of scientific papers have been published since 2008, and more are expected as confidentiality clauses expire. This volume is, however, the first GEUS Bulletin to be published as a direct consequence of the GEUS–industry collaboration

Scientific results from the deepened Lopra-1 borehole, Faroe Islands: Petroleum geochemistry of the deepened Lopra-1/1A re-entry well, Faroe Islands

The Lopra-1/1A re-entry well was drilled as a stratigraphic test with no immediate exploration objectives. Hence, petroleum geochemical studies were of limited extent, and restricted to non-destructive analyses. The presence of natural petroleum hydrocarbons could not be confirmed with certainty, but hydrocarbons extracted from the hydrochloric acid solute of a calcite vug present in RSWC #1 (3543 m), may represent indigenous petroleum since hydrocarbon-bearing fluid inclusions have been reported from the same sample. These hydrocarbons show some similarities to petroleum generatedfrom the Upper Jurassic – Lower Cretaceous Kimmeridge Clay type source rocks present in surrounding areas. Except for this sample, the results generally show the presence of a variety of contaminantsof different origins such as ‘naturally greasy fingers’ (squalene and cholesterol), cosmetics such as chap stick or hand lotion (e.g. esters such as butyl-stearate, stearyl-palmitate, vitamin A), plasticisers (phthalates), diesel oil and ‘pipe dope’