Geological Survey of Denmark and Greenland Bulletin 6, 51-71 51Geological Survey of Denmark and Greenland Bulletin 5, 51–71 © GEUS, 2004 A new Middle–Upper Jurassic succession on Hold with Hope, North-East Greenland Henrik Vosgerau, Michael Larsen, Stefan Piasecki and Jens Therkelsen A succession of marine, Jurassic sediments was recently discovered on Hold with Hope, North- East Greenland. The discovery shows that the area was covered by the sea during Middle–Late Jurassic transgressive events and thus adds to the understanding of the palaeogeography of the area. The Jurassic succession on northern Hold with Hope is exposed in the hangingwalls of small fault blocks formed by rifting in Late Jurassic – Early Cretaceous times. It unconformably overlies Lower Triassic siltstones and sandstones and is overlain by Lower Cretaceous coarse- grained sandstones with an angular unconformity. The succession is up to 360 m thick and includes sandstones of the Lower–Upper Callovian Pelion and Middle–Upper Oxfordian Payer Dal Formations (Vardekløft Group) and heteroliths and mudstones of the Upper Oxfordian – Lower Kimmeridgian Bernbjerg Formation (Hall Bredning Group). The Pelion Formation in- cludes the new Spath Plateau Member (defined herein). The palaeogeographic setting was a narrow rift-controlled embayment along the western margin of the rifted Jurassic seaway between Greenland and Norway. It was open to marine circulation to the south as indicated by the distribution and lateral facies variations and a domi- nant south-westwards marine palaeocurrent direction. The Pelion and Payer Dal Formations represent upper shoreface and tidally influenced delta deposits formed by the migration of dunes in distributary channels and mouthbars over the delta front. The boundary between the two formations is unconformable and represents a Late Callovian – Middle Oxfordian hiatus. It is interpreted to have formed by subaerial erosion related to a sea-level fall combined with minor tilting of fault blocks and erosion of uplifted block crests. In Late Jurassic time, the sand-rich depositional systems of the Pelion and Payer Dal Forma- tions drowned and offshore transition – lower shoreface heteroliths and offshore mudstones of the Bernbjerg Formation accumulated. The fault block crest forming the eastern basin margin was inundated by a rise in relative sea level. Major fault activity probably occurred in latest Jurassic – Early Cretaceous times when the major fault block originally defining the Hold with Hope basin was split into smaller blocks. Keywords: Hall Bredning Group, Hold with Hope, lithostratigraphy, North-East Greenland, palaeogeography, sedimentology, shallow marine, Spath Plateau Member, Vardekløft Group H.V.*, M.L., S.P. & J.T.‡, Geological Survey of Denmark and Greenland, Øster Voldgade 10, DK-1350 Copenhagen K, Denmark. E-mail: mil@geus.dk Present addresses: *Roskilde Amt, Køgevej 80, DK-4000 Roskilde, Denmark. ‡Skude & Jacobsen, Næstvedvej 1, DK-4760 Vordingborg, Denmark. GEUS Bulletin no 5.pmd 29-10-2004, 11:1451 52 A new Middle–Upper Jurassic succession, up to 360 m thick, was found recently on northern Hold with Hope, North-East Greenland (Fig. 1; Stemmerik et al. 1997; Kelly et al. 1998; Larsen et al. 1998). It spans the Early Callovian – Early Kimmeridgian time interval as indi- cated by dinoflagellate cysts and ammonites, and con- sists of coarse-grained sandstones overlain by hetero- liths and mudstones. The sandstone-dominated lower part of the succession assigned here to the Pelion For- mation was originally studied by Koch (1932) and Maync (1949) and was tentatively given an Early Cre- taceous age, although W. Maync noted the resemblance to theMiddle Jurassic succession on Wollaston Forland. The apparent absence of Jurassic sediments in the Hold with Hope area was explained differently by Maync (1947), Donovan (1957), Surlyk (1977) and Stem- merik et al. (1993). Maync (1947) and Surlyk (1977) suggested that during the Jurassic the area formed a landmass between the Wollaston Forland Basin to the north and the Jameson Land Basin to the south, imply- ing that the lack of sediments was primarily due to non-deposition. Donovan (1957) in contrary found it 20ºW 16ºW24ºW28 76 75 76ºN 74ºN 72ºN Greenland Store Koldewey Wollaston Forland Milne Land Jameson Land Traill Ø Geographical Society Ø Kuhn Ø Clavering Ø Fig. 2 Hold with Hope PDMF DCF Jurassic Fault Dombjerg–Clavering FaultDCF 100 km Post-Devonian Main FaultPDMF Fig. 1. Map of East Greenland showing the distribution of Jurassic sediments and major faults. Rectangle marks the investigated area on northern Hold with Hope, shown in more detail in Figure 2. Modified from Koch & Haller (1971) and Surlyk et al. (1973). GEUS Bulletin no 5.pmd 29-10-2004, 11:1452 53 most likely that the absence was secondary owing to pre-Aptian erosion of the Jurassic rocks. Based on com- parison with nearby Clavering Ø, Stemmerik et al. (1993) suggested that Middle–Upper Jurassic sediments were present in the subsurface east of the continua- tion of the Dombjerg–Clavering Fault on Hold with Hope (Fig. 1, DCF). The present investigations confirm that Hold with Hope formed a landmass between the Wollaston For- land and Jameson Land Basins during much of the Middle Jurassic time interval. The discovery on Hold with Hope of a marine succession of Early Callovian – Kimmeridgian age, however, shows that the land mass was flooded in late Middle Jurassic time and contin- ued to be sea-covered for most of the remaining Juras- sic period. The Jurassic succession on Hold with Hope is sub- divided into shallow marine sandstones of the Pelion and Payer Dal Formations (Vardekløft Group) and lower shoreface – offshore transition heteroliths and offshore mudstones of the Bernbjerg Formation (Hall Bredning Group). The Pelion Formation includes the new Spath Plateau Member, which contains abundant sandy hete- roliths in contrast to the dominant clean sandstone li- thology of the Pelion Formation. The sedimentary facies of the units are described and the depositional envi- ronments interpreted. The Jurassic succession is placed within a regional framework including the Wollaston Forland and Jameson Land Basins to the north and south, respectively. Ice Undifferentiated superficial deposits Dolerite sill Plateau basalt Normal fault Inferred fault Locality Cross-section (log panel) Paleocene Lower Cretaceous Middle and Upper Jurassic Lower Triassic Permian Crystalline basement 1 8 9 3B 765 4 3A 3C 3D 3E 2 3 ■■ ■■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■■ ■■ ■■ ■ ■ ■ ■ ■■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■■ ■■ ■■ ■ ■ ■■ ■ ■ ■ ■ ■ ■ Steensby Bjerg Gael Hamke Bugt Diener Bjerg Sortelv Spath Plateau Fo sd al en Stensiö Plateau 21º00'W 21º15'W 74º00'N Hold with Hope G ul el v Blåe lv ■ ■ ■■ ■■ ■ ■ ■■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■■ ■ ■ ■ ■ ■ 2 km 73º55'N Fig. 2. Geological map of part of northern Hold with Hope including position of localities mentioned in text. The composite section from Gulelv (Fig. 5) was compiled from five part-sections (A–E). The solid lines show schematically the orientation of the NE–SW and NW–SE log panels in Figures 7 and 8, respectively. GEUS Bulletin no 5.pmd 29-10-2004, 11:1453 54 Geological setting The Late Palaeozoic – Mesozoic extensional basin com- plex in East Greenland is about 700 km long in a north– south direction. This complex is situated over structur- ally controlled en echelon troughs and forms a wedge- shaped embayment with the narrowest onshore part to the north. Jurassic sediments are present in the Wollaston Forland and Jameson Land Basins situated on the western margin of the rift complex. In both basins, sediment transport in Middle Jurassic time was mainly longitudinal from north to south along a low gradient basin floor, which was not differentiated into a shelf, slope and deep-water basin (Surlyk 1977, 1990, 1991; Surlyk et al. 1981; Surlyk & Clemmensen 1983). In the Wollaston Forland Basin, rifting was initiated in Middle Jurassic time, and marine Bajocian–Bathonian sandstones onlap weathered Caledonian basement rocks or Upper Permian carbonates. Deposition took place on the hangingwall of wide W–SW-tilted fault blocks. Jurassic rifting culminated in the Volgian with strong rotational block faulting associated with con- glomeratic submarine fan sedimentation (Surlyk 1978). During this tectonic episode, the wide fault blocks origi- nally defining the Wollaston Forland Basin were split into smaller blocks (Vischer 1943; Surlyk 1978). The Jurassic sediments on Hold with Hope occur on the hangingwall of small fault blocks that dip mainly towards the west and south-west (Fig. 2). Bedding planes within the Triassic and Jurassic successions seem tobeparallelwhereas theboundary to theoverlyingCre- taceous succession is an angular unconformity (Fig. 3). The Jurassic succession shows marked lateral thick- ness variations depending on its position on the hang- ingwall. The thickness increases down-dip whereas it is missing up-dip due to Early Cretaceous erosion on some of the block crests. Faults locally cut the Triassic and Jurassic successions, but not the overlying Creta- ceous succession showing that fault activity took place in post-Kimmeridgian, but pre-Barremian time (Fig. 3). Most faults in the area, however, were reactivated dur- ing Cretaceous and Cenozoic times. Stratigraphy and sedimentology The Jurassic succession on Hold with Hope is subdi- vided into lithostratigraphic units known from Wolla- ston Forland and Kuhn Ø (Fig. 4). Stratigraphic ages of the Jurassic succession are based on ammonites and dinoflagellate cysts (Piasecki et al. 2004, this volume). The oldest Jurassic ammonite found on northern Hold with Hope is Cranocephalites sp. indicating the Upper Bajocian C. pompeckji Chronozone (J.H. Callomon and P. Alsen, personal communications 1997). The ammo- nite was, however, not found in situ but in the basal Cretaceous conglomerate at Locality 4 and c. 150 m east of Locality 8 (Fig. 2). The Jurassic outcrops occur between Stensiö Pla- teau in the west and Diener Bjerg in the east (Fig. 2). Towards the south, the Jurassic sediments are exposed along the eastern side of the Gulelv river and on the southern side of the Sortelv river. A composite section, 360 m thick, was measured in a north–south direction along Gulelv on the hangingwall of a fault block dip- ping c. 15º towards the SSW and comprises segments 3A–E (Figs 5, 6). Lateral facies variations are illustrated by cross-sections oriented parallel (NE–SW) and per- pendicular (NW–SE) to the overall palaeocurrent di- rection (Figs 2, 7, 8). Pelion Formation The Pelion Formation in the Jameson Land and Wolla- ston Forland Basins consists of shallow marine, me- dium- to coarse-grained sandstones of Late Bajocian – Late Callovian age (Engkilde & Surlyk 2003). On Hold Pb E W LC MJ Tr Tr Fig. 3. Triassic–Paleocene succession exposed at Steensby Bjerg, northern Hold with Hope, viewed towards the south. The Triassic (Tr) and Middle Jurassic (MJ) sediments dip towards the south- west and are unconformably overlain by Lower Cretaceous (LC) sediments. A post-Kimmeridgian – pre-Barremian normal fault striking north–south offsets the Triassic and Jurassic sediments by at least 30 m. View towards the south. From Larsen et al. (1998). The exposure shown is c. 200 m high and capped by Paleocene basalts (Pb). GEUS Bulletin no 5.pmd 29-10-2004, 11:1454 55 15 9. 4 15 4. 1 16 4. 4 16 9. 2 17 3 L L L L Ba jo ci an Ba th on ia n Ju ra ss ic C al lo vi an O xf or di an K im m er id gi an St ag e Sy st em M a M M M U U U U Traill Ø and Geographical Society Ø W E W E S N Hold with Hope Wollaston Forland and Kuhn Ø Be rn bj er g Be rn bj er g O ly m pe n Fo ss ilb j Fb PP Pe lio n Br is to l E lv Be rn bj er g Pa ye r D al Be rn bj er g Ja ko bs st ig en Pa ye r D al Pe lio n Ba st ia ns D al M us lin ge bj er g Pe lio n Sandstone Siltstone Heterolithic sandstone Mudstone Legend Ammonite Coal Conglomerate C. cordatum P. baylei R. cymodoce A. mutabilis A. eudoxus A. autissiodorensis Subboreal–Boreal Ammonite Zonation C. densiplicatum C. tenuiserratum A. glosense A. serratum A. regulare A. rosenkrantzi P. plicatilis G. transversarium P. bifurcatus R. pseudocordata Q. mariae Q. lamberti P. athleta E. coronatum K. jason S. calloviense P. koenigi C. nordenskjoeldi M. herveyi C. discus O. orbis P. hodsoni M. morrisi T. subcontractus P. progracilis A. tenuiplicatus Z. zigzag P. parkinsoni G. garantiana N. subfurcatum C. apertum C. calyx C. variabile A. cranocephaloide A. ishmae A. greenlandicus A. arcticus C. pompeckji C. indistinctus C. borealis Fig. 4. Jurassic litho- and biostratigraphy (Lower Jurassic and Volgian not included) of the Traill Ø – Geographical Society Ø region, Hold with Hope and Wollaston Forland. Based on Surlyk (1977, 1978, 1990, 1991), Price & Whitham (1997), Alsgaard et al. (2003), Alsen & Surlyk (2004, this volume), Vosgerau et al. (2004, this volume) and own observations in the Traill Ø and northern Hold with Hope areas. Fossilbj/Fb, Fossilbjerget; PP, Pelion (Parnas Mb). GEUS Bulletin no 5.pmd 29-10-2004, 11:1455 56 Lo w er s an ds to ne u ni t Sp at h Pl at ea u M b Sp at h Pl at ea u M b U gp ik R av in e M b M Mud Sand F C Gr M Mud Sand F C Gr M Mud Sand F C Gr Tr ia ss ic Pe lio n Fm Pe lio n Fm Be rn bj er g Fm Be rn bj er g Fm Pa ye r D al F m C re ta ce ou s ? 120 110 100 90 80 70 60 50 40 30 20 10 0 250 240 230 220 210 200 190 180 170 160 150 140 130 360 350 340 330 260 m No exposure No exposure No exposure GEUS Bulletin no 5.pmd 29-10-2004, 11:1456 57 with Hope, a Lower–Middle Callovian sandy succes- sion, c. 190 m thick, overlying the Lower Triassic Wordie Creek Formation is referred to the Pelion Formation (Fig. 5). The succession is divided into two units. The lower unit is 30–40 m thick and consists of medium- to coarse-grained sandstones topped by silty, fine-grained sandstones. The upper unit is up to 155 m thick and differs from the clean sandstones that typify the for- mation by containing abundant sandy heteroliths inter- bedded with cross-bedded sandstones and is included in the Spath Plateau Member (Fig. 5). The lower sand- stone unit and the Spath Plateau Member are described and interpreted separately below; the latter member is defined formally as a new member of the Pelion For- mation. Structureless Trough cross-bedding Planar and trough cross-bedding Structureless Planar and trough cross-bedding Wave ripple cross-lamination Faint ripple form sets Hummocky cross-stratification Pebbles Plant fragments Log Bivalve Ammonite Belemnite Sedimentary structures Biota Miscellaneous features Palaeocurrent direction Orientation of wave ripple crest Parallel lamination Upper shoreface Lower–middle shoreface Facies associations Offshore – lower shoreface Offshore Faint ripple form sets Cross-lamination Wave ripple cross-lamination Curvolithos Helminthopsis? Chondrites Bioturbation moderate Bioturbation strong Diplocraterion Monocraterion Ophiomorpha Planolites Bioturbation weak Trace fossilsMudstone drapes and clasts Fig. 5. Composite sedimentary section of the Middle–Upper Jurassic succes- sion at Gulelv (Locality 3). The section was compiled from five part-sections located in a north–south direction along Gulelv (Figs 2, 6). Modified from Larsen et al. (1998). GEUS Bulletin no 5.pmd 29-10-2004, 11:1457 58 Lower sandstone unit The lower sandstone unit overlies siltstones and fine- grained sandstones of the Lower Triassic Wordie Creek Formation with a sharp erosional boundary. The up- per boundary is placed where coarse-grained sand- stones are overlain by silty, very fine-grained sand- stones of the Spath Plateau Member (Figs 5, 9). The ammonite Cadoceras cf. breve indicating the Lower Callovian C. apertum Chronozone (J.H. Callo- mon and P. Alsen, personal communications 1997) was found 10 m above the Triassic–Jurassic boundary at Stensiö Plateau (Fig. 2, Locality 1). The basal part of the unit seems to be younger east of Stensiö Plateau (Fig. 2, Localities 4–9) where dinoflagellate cysts indi- cate the Lower Callovian P. koenigi Chronozone. The ageof the upper boundary is constrained by an ammo- nite and by dinoflagellate cysts found in the basal part of the overlying Spath Plateau Member indicating the Lower Callovian P. koenigi Chronozone (see below). The lower sandstone unit consists of pebbly, me- dium- to coarse-grained quartz sandstones, which are trough cross-bedded with sets up to 0.5 m thick or locally appear structureless. Small scour-fills with peb- bles, up to 3 cm in diameter, are common. Dip-direc- tions of foresets show a dominance towards the SW, but directions towards the NW also occur (Fig. 10). The sandstones commonly form coarsening-upwards units, 6–8 m thick, which locally are overlain by an erosionally based pebbly sandstone lag. The top part of the coarsening-upwards units is commonly calcite cemented and contains abundant vertical trace fossils of Diplocraterion habichi. Other trace fossils include Monocraterion tentaculatum and locally Ophiomorpha nodosa. Belemnites, bivalves and silicified wood are common. The unit is slightly finer grained in places and medium-grained sandstones occur at Locality 1, Stensiö Plateau (Fig. 8). They contain low-relief scour surfaces draped by organic-rich mudstone and are strongly bioturbated with both horizontal and vertical burrows. The lower sandstone unit increases in thick- ness from c. 30 to 40 m from the SW towards the NE (Fig. 7). Deposition took place in a marine environment as reflected by marine macrofossils and trace fossils. The coarse-grained and pebbly sandstones and the domi- nance of vertical burrows suggest shallow-water depo- sition under high-energy conditions. The scour-fills are interpreted to have been formed by strong currents related to storm surges (e.g. Clifton et al. 1971; Hunter et al. 1979). The trough cross-bedded sandstones prob- ably reflect 3-D dunes migrating seawards to the south- west in rip channels and partly longshore in runnels towards the north-west. Erosionally-based pebbly sand- stones with marine macrofossils form the uppermost beds of some of the coarsening-upwards units and are interpreted as marine lag deposits, formed by wave winnowing of underlying upper shoreface and fore- shore deposits. The coarsening-upwards units are in- terpreted to have formed mainly by shallow marine shoreface progradation. The probable source of the calcite cement in the top part of the coarsening-up- 3D3C3B3A 3E Payer Dal Fm Bernbjerg Fm ? 100 m Lower Triassic N S 100 m Pelion and Payer Dal Fms Bernbjerg Fm Lower Cretaceous Unconformity Pelion Fm Lower Triassic SPM LU Fig. 6. Sketch of Triassic–Cretaceous succession exposed in a fault block on the eastern side of the Gulelv river (Fig. 2). The location of the part-sections that make up the composite section in Figure 5 are shown. The Triassic and Jurassic sediments dip c. 15° towards SSW and are unconformably overlain by Cretaceous sediments, which dip c. 10° towards the south. An angular unconform- ity between the Pelion and Payer Dal Formations is observed on the north-facing valleyside at 3C (see Fig. 11). LU, Lower sandstone unit; SPM, Spath Plateau Member. GEUS Bulletin no 5.pmd 29-10-2004, 11:1458 59 wards units is biogenic carbonate derived from calcar- eous shells accumulated on the marine omission sur- faces (Alsgaard et al. 2003; Engkilde & Surlyk 2003). The strong bioturbation and the thin mudstone lay- ers in the medium-grained sandstones at Stensiö Pla- teau suggest deposition under lower energy conditions. The mudstone drapes on the scour-surfaces formed by suspension fall-out during fair-weather conditions following erosional storm events. The sandstones were probably deposited in a slightly deeper, middle shore- face environment, than the medium- to coarse-grained sandstones that dominate the lower sandstone unit east of Stensiö Plateau. The decrease in thickness of the sandstone unit from NE to SW combined with the dominant south-west- wards palaeocurrent directions may reflect a NE–SW proximal–distal trend. In the proximal areas, a large sediment supply may have delayed the overall drown- ing recorded by the boundary to the overlying Spath Plateau Member. The increase in thickness towards the NE may, however, also reflect the relief of the palaeo- shoreface. Spath Plateau Member new member General. The member comprises mainly cross-bed- ded sandstones and sandy heteroliths forming the up- per part of the Pelion Formation on northern Hold with Hope. Name. After the ice-covered basalt plateau south-west of Gulelv, northern Hold with Hope. Type locality. East side of Gulelv (Figs 2, 6, Locality 3) where the composite type section (Fig. 5) is defined from sub-sections A–C. Thickness. 155 m. Lithology. The Spath Plateau Member consists of quartzitic sandstones and sandy heteroliths. A silty, very fine-grained sandstone bed occurs in the basal part of the member. Belemnites, bivalves, silicified and coalified wood and impressions of leaf fragments are common. Boundaries. The lower boundary is marked by an abrupt change from coarse-grained sandstone of the lower sandstone unit of the Pelion Formation to silty, fine-grained sandstone. The upper boundary is sharp and erosional and is overlain by pebbly sandstone and sandy heteroliths of the Payer Dal Formation. Distribution. The member occurs on northern Hold with Hope. Age. Early–Late Callovian based on an ammonite found at the base of the member and dinoflagellate cysts (Fig. 7, Locality 6). The ammonite is a microconch and re- sembles Cadoceras septentrionale indicating the lower- most part of the LowerCallovian P. koenigi Chronozone (P. Alsen, personal communication 1998). Dinoflagel- late cysts from the base of the member also indicate the C. apertum – P. koenigi Chronozones (Piasecki et al. 2004, this volume). Dinoflagellate cysts in the up- per part of the member indicate the Upper Callovian P.athletaChronozone(Piaseckietal.2004, thisvolume). Facies description. The basal part of the member con- sists of dark brown, silty sandstones forming a 6 m thick marker bed, situated 30–40 m above the base of the Jurassic succession (Figs 5, 7, 9). The basal 0.5 m of the bed locally contain scattered fine pebbles up to 6 mm in diameter, but otherwise the unit coarsens upwards from silty, very fine-grained sandstone into silty fine-grained sandstone. The sandstones are hori- zontally laminated, structureless or show subtle wave or current cross-lamination with thin organic-rich mudstone drapes, but primary structures are to a large extent obscured due to weathering or strong bioturba- tion. In a few places, laminae of silty sandstone are deflected around small, elongate carbonate-cemented concretions. Coalified wood fragments up to 30 cm long and belemnites are abundant in the basal part of the bed, and a few bivalves and gastropods were found immediately above the lower boundary at Locality 6 (Fig. 7) together with the ammonite Cadoceras septentrionale. The organic content (TOC) is low, about 1 wt%. The fine-grained marker bed forms the base of the Spath Plateau Member and sharply overlies trough cross-bedded sandstones or conglomerates of the lower sandstone unit of the Pelion Formation. However, at Locality 9 (Fig. 8), the basal unit of the member con- sists of a ripple cross-laminated sandy heterolith unit, c. 0.4 m thick, followed by medium- to coarse-grained, planar cross-bedded sandstones. The upper boundary to the overlying ripple cross-laminated sandy hetero- liths is gradational. GEUS Bulletin no 5.pmd 29-10-2004, 11:1459 60 100 m 90 80 70 60 50 40 30 20 10 0 80 m 70 200 m 190 180 170 160 150 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 60 50 40 30 20 10 0 Sand Sand Sand Sand 0 10 20 30 40 50 60 70 80 m ? SW (Distal) 2 3 4 5 ~ 2450 m ~ 1050 m ~ 130 m ~ 650 m Lo w er u ni t Sp at h Pl at ea u M b Pe lio n Fm Pa ye r D al F m GEUS Bulletin no 5.pmd 29-10-2004, 11:1460 61 Fig. 7. Log panel giving a broadly NE (proximal) to SW (distal) cross-section. For legend, see Fig. 5; for localities, see Fig. 2. 10 0 20 30 40 50 60 70 m 40 m 30 20 10 0 10 0 60 m 50 40 30 20 Sand SandSand T ri as si c Ju ra ss ic S pa th P la te au M b C re ta ce ou s Base of distributary channel fill deposits NE (Proximal) 6 7 8 ~ 200 m ~ 1325 m GEUS Bulletin no 5.pmd 29-10-2004, 11:1461 62 The bulk of the member is made up of heteroliths forming units up to 10 m thick of cross-laminated, fine- to medium-grained sandstones with thin organic-rich mudstone drapes. Both symmetrical and asymmetrical ripples, 1–5 cm high and with wavelengths up to 10 cm, occur. The heteroliths locally form cross-strata, up to 1.5 m thick, with very low-angle foresets and set boundaries marked by indistinct toesets of dark, sandy mudstones, a few centimetres thick. Scour surfaces with a relief of up to 20 cm are common in the heteroliths. Locally, structureless sandstones overlie the surfaces. The degree of bioturbation varies from moderate to high (up to 100%) and the trace fossil assemblage in- cludes Planolites beverleyensis, Curvolithos multiplex, Monocraterion tentaculatum, Diplocraterion habichi and possibly Helminthopsis magna. Silicified and coalified wood fragments up to 1 m long, together with impressions of leaf fragments, are abundant and belemnites occur locally. Two types of cross-bedded sandstones occur closely associated with the heteroliths in the Spath Plateau Member. They both show foresets mainly dipping to- wards the south-west (Fig. 10). The first type consists of planar or trough cross-bedded, fine- to coarse- grained sandstones occasionally with pebbles. Foresets are generally tangential and commonly separated by single and in places double, organic-rich mudstone drapes. Backflow ripples and reactivation surfaces oc- cur locally. The sets are 0.5–5 m thick and form cosets up to 25 m thick. Set-boundaries are defined by or- ganic-rich silty sandstone beds 1–10 cm thick, repre- senting distal toesets. In one place, however, the toesets form a lenticular body of organic-rich shale, 40 m long and 0.5 m thick, with gently inclined laminae (to SW). The cross-bedded, coarse-grained sandstones com- monly overlie ripple cross-laminated sandy heteroliths with a sharp erosional boundary, and contain belem- nites, bivalve shells and coalified wood. The degree of bioturbation is low and the trace fossils include verti- cal burrows of Monocraterion tentaculatum, Diplocra- terion habichi and Arenicolites isp. The first type of cross-bedded sandstones form a c. 40 m thick succes- sion in the lower part of the Spath Plateau Member at Locality 9, Diener Bjerg, whereas heteroliths are abun- dant in the lower part at the other localities (Figs 7, 8). The second type of cross-bedded sandstones is fine- 0 10 20 30 40 50 60 70 80 m 20 m 10 0 10 0 20 30 40 50 60 70 m Lo w er u ni t Pe lio n Fm T ri as si c Ju ra ss ic C re ta ce ou s Sp at h Pl at ea u M b NW SE SandSand Sand 1 8 9~ 8 km ~ 5 km Fig. 8. Log panel giving a NW–SE strike section through the Jurassic succession. For legend, see Fig. 5; for localities, see Fig. 2. GEUS Bulletin no 5.pmd 29-10-2004, 11:1462 63 to medium-grained and consists of up to 5 m thick sets of low-angle master beds separated by thinner cross- bedded or ripple cross-laminated sets. The latter com- monly show climbing ripple cross-lamination or lo- cally bi-directional cross-laminae. The surfaces of the low-angle master beds may be wave or current rip- pled and separated by thin mudstone drapes. Set thick- ness is 1–5 m. The lower boundary to ripple laminated sandy heteroliths is generally gradational. The sand- stones contain belemnites, bivalve shells and coalified wood. The degree of bioturbation is moderate to high. Trace fossils include vertical burrows of Monocraterion tentaculatum, Diplocraterion habichi and Arenicolites isp., forms that are also common in the first type of sandstones, together with horizontal burrows of Planolites beverleyensis and possibly Helminthopsis magna in the intervening mud drapes. Trough cross-bedded sandstones similar to those in the lower sandstone unit of the Pelion Formation oc- cur locally in the Spath Plateau Member (Fig. 7). They commonly form coarsening-upwards successions, up to 5 m thick, the most complete of which have a lower part consisting of well-sorted, fine- to medium-grained sandstone with indistinct ripple cross-lamination, trough cross-bedding and shallow scour fills. The scour fills are 10–30 cm thick and are marked by thin, organic- rich mudstone layers above the lower erosional bounda- ries followed by laminated or structureless sandstones. The upper part of the coarsening-upwards units con- sists of trough cross-bedded, medium- to coarse-grained sandstones. Foresets dip mainly towards the south, but dip-directions towards the west and east also occur (Fig. 10). The upper part is commonly calcite cemented and capped by a sharp surface from which abundant Diplocraterion habichi descend; other trace fossils in the upper levels include Monocraterion tentaculatum and occasional Ophiomorpha nodosa. Horizontal bur- rows of Planolites beverleyensis are limited to the lower part of the coarsening-upwards units. Belemnites, bi- valves and silicified wood are common. Facies interpretation. The laminated silty sandstone 5 m SPM LU Pelion Fm Tr ias sic Fig. 9. Triassic siltstones and sandstones overlain by concretionary sandstones of the lower sandstone unit (LU) of the Pelion Formation. A marine drowning surface (dashed line) separates the lower sandstone unit from an overlying dark brown silty sandstone bed which form the basal part of the Spath Plateau Member (SPM), Pelion Formation. Fig. 2, Locality 6. GEUS Bulletin no 5.pmd 29-10-2004, 11:1463 64 bed of the basal Spath Plateau Member (except at Lo- cality 9), was deposited in a marine environment as reflected by the marine dinoflagellate cysts and abun- dant belemnites. The horizontal lamination was formed by deposition from suspension fall-out whereas the subtle cross-lamination was probably formed by wave- induced currents in the offshore transition to lower shoreface zone. The sharp boundary to the underlying upper shoreface sandstones of the lower sandstone unit represents a drowning surface. At Locality 9, Die- ner Bjerg, this surface is overlain by a sandy heterolith unit, c. 0.4 m thick, interpreted as having been depos- ited in the lower to middle shoreface zone. This lateral facies variation suggests that the palaeo-water depth decreased from west to east. The alternation of ripple cross-laminated sandstones 25 20 15 10 5 % 50 40 30 20 10 5 % 50 40 30 20 10 5 % 25 1520 10 5 % 25 20 15 10 5 % 15 10 5 % N=11 V=243° N=9 V=221° N=11 V=175° N=14 V=338° N=47 V=220° N=8 V=231° Pelion Fm (lower sandstone unit) Pelion Fm (Spath Plateau Member) Trough cross-bedding Trough and planar cross-bedding Trough cross-bedding Wave ripple crest orientation Trough and planar cross- bedding, and low-angle master bedding Trough cross-bedding Payer Dal Fm Bernbjerg Fm Fig. 10. Palaeocurrent and wave-ripple data from the Pelion, Payer Dal and Bernbjerg Formations. Rose diagrams are shown as true area plots. V, vector mean; N, number of measurements. GEUS Bulletin no 5.pmd 29-10-2004, 11:1464 65 and mudstone drapes reflects varying energy condi- tions and may be related to the alternation of fair- weather and storm-wave processes and perhaps tidal currents. The strongly bioturbated heteroliths reflect periods of slow sedimentation and little physical re- working whereas the scour surfaces and the overlying structureless sandstones which form part of the facies are interpreted as having formed by strong currents related to storm surges (Clifton et al. 1971; Hunter et al. 1979; Nemec & Steel 1984). The abundant plant debris suggests a significant sediment supply from land. The two types of cross-bedded sandstones are in- terpreted to represent SSW-migrating sandwaves. They were modified by waves and opposing tidal currents as seen by the presence of wave-ripples, mud drapes, reactivation surfaces and bimodal cross-lamination (Visser 1980; Boersma & Terwindt 1981; Wood & Hopkins 1989). The first type of cross-bedded sand- stones was formed in shallow water, possibly the up- per shoreface, as seen by the coarse grain-size and low degree of bioturbation. The sharp erosional lower boundaries to lower–middle shoreface heteroliths sug- gest that the migration of sandwaves took place in distributary channels. The marked lateral facies varia- tion seen between Locality 9 and the other localities suggests that the thick cross-bedded succession at Lo- cality 9 may represent a major distributary channel fill. The second type of cross-bedded sandstones was formed in deeper water than the first type, as reflected by the generally finer grain-size, stronger bioturbation and the gradational boundary to underlying lower– middle shorefaceheteroliths.The compound cross-bed- ded sandstones with climbing ripple cross-laminated sets on the low-angle master bedding reflect suspen- sion fall-out into deeper water and were possibly de- posited in mouthbars (Elliott 1974; Gjelberg & Steel 1995). The trough cross-bedded sandstones are similar to those in the lower sandstone unit of the Pelion Forma- tion and are similarly interpreted as having formed by migration of 3-D dunes in a high energy, shallow ma- rine environment. The coarse grain size of the trough cross-beds from the upper part of the coarsening-up- wards units suggests sediment supply from nearby distributary channels. The dominant southwards palaeo- current direction indicates that land was situated to- wards the north, but the large variation in the palaeo- current measurements and the limited dataset preclude detailed interpretation of the palaeo-shoreline orienta- tion. The coarsening-upwards units are interpreted to reflect progradation in the middle to upper shoreface. Payer Dal Formation In the type area on Kuhn Ø, the Payer Dal Formation consists of fine- to coarse-grained quartz sandstones locally with pebbly sandstone lags rich in marine bi- valves and belemnites (Alsgaard et al. 2003). The for- mation is subdivided into a lower and an upper unit that have an Early–Middle Oxfordian and early Late Oxfordian age, respectively (Fig. 4). On Hold with Hope, a succession of cross-bedded, medium- to coarse-grained quartz sandstones, pebbly sandstone lags and sandy heteroliths overlying the Pelion Forma- tion is referred to the Payer Dal Formation. E W Lower Cretaceous Payer Dal Fm Pelion Fm(Spath Plateau Mb) 15 m Fig. 11. The Spath Plateau Member (Pelion Formation), Payer Dal Formation and overlying Cretaceous sandstones. Note the slight angular discordance at the unconformity between the Pelion and Payer Dal Formations (dashed line). Fig. 2, Locality 3C; view towards south. GEUS Bulletin no 5.pmd 29-10-2004, 11:1465 66 The age of the Payer Dal Formation on Hold with Hope is Middle–Late Oxfordian. Dinoflagellate cysts from the lower part of the Formation indicate the Mid- dle–Upper Oxfordian C. tenuiserratum – A. glosense Chronozones, similar to the upper unit of the Payer Dal Formation on Kuhn Ø. This suggests that the boundary between the Pelion and Payer Dal Forma- tions on Hold with Hope represents a Late Callovian – Middle Oxfordian hiatus (Fig. 4). The formation is exposed at Localities 2 and 3 (Figs 2, 5, 7). The lower boundary is only exposed at Local- ity 3, where it is represented by an erosional surface forming a minor angular unconformity between the Pelion and Payer Dal Formations (Fig. 11). The sur- face is overlain by a pebbly sandstone lag, up to 0.5 m thick, of quartz pebbles 3–5 mm in diameter, belem- nites, bivalves and small logs, up to 0.4 m long. The lag is overlain by a coarse- to very coarse-grained sand- stone succession, c. 15 m thick, which fines slightly upwards. The succession is dominated by trough cross- bedding but small sets of planar cross-beds and peb- bly sandstone lags also occur. Dip directions of foresets are mainly towards the SW (Fig. 10). Pavements of bivalves are common, whereas belemnites, logs and rounded mudstone clasts, up to 5 cm in diameter, oc- cur locally. The sandstone succession is capped by a sharp surface overlain by an overall coarsening-up- wards unit (c. 25 m thick) of ripple cross-laminated sandy heteroliths, similar to those in the underlying Spath Plateau Member. At Locality 2, the formation is at least 70 m thick and consists of alternating ripple cross-laminated sandy heteroliths and sets of planar or trough cross-bedded, coarse-grained sandstones simi- lar to the first type of cross-bedded sandstones of the Spath Plateau Member. The foresets dip towards the south-west (Fig. 10). The upper boundary to the Bernbjerg Formation is covered by scree, but is prob- ably situated somewhere between 223 m and 234 m in the composite section at Locality 3 (Fig. 5). The basal pebbly sandstone at Locality 3 is inter- preted as a marine lag deposit due to the coarse grain size, the presence of marine macrofossils and the ero- sional base. The overlying cross-bedded sandstone succession was deposited in a high energy, shallow marine environment as testified by the coarse grain size, the pebbly sandstone lags and the marine macrofossils. The cross-bedded sandstones are inter- preted to reflect the seawards migration of dunes in the upper shoreface. The coarse grain size of the sand- stone succession and the occurrence of logs and rounded clay clasts suggest sediment supply from nearby distributary channels. The sandstone succes- sion is topped by a drowning surface. A slightly different depositional environment is re- corded by the succession at Locality 2 where planar and trough cross-bedded distributary channel-fill sand- stones alternate with lower–middle shoreface hetero- liths. These facies are very similar to the facies of the underlying Spath Plateau Member and are similarly interpreted to reflect migration of dunes in distributary channels and mouth bars associated with tidally influ- enced deltas (see above). The considerable thickness variation of the Payer Dal Formation between Localities 2 and 3, together Cretaceous Bernbjerg Fm Fig. 12. Structureless and horizontally laminated dark mudstones of the Bernbjerg Formation erosionally overlain by Cretaceous sandstone (Fig. 6, Locality 3E; 340–360 m in Fig. 5). Person (encircled) for scale. GEUS Bulletin no 5.pmd 29-10-2004, 11:1466 67 with the presence of a minor angular unconformity at the base of the formation, might reflect differential subsidence due to the onset of fault-block tilting. Bernbjerg Formation The Upper Oxfordian – Lower Volgian Bernbjerg For- mation in Wollaston Forland is dominated by dark- grey to black mudstones and strongly bioturbated hete- roliths (Surlyk 1977; Surlyk & Clemmensen 1983). On Hold with Hope, the formation is poorly exposed along the Gulelv river (Figs 2, 6) where it is estimated to be c. 130 m thick based mainly on simple geometrical calculations. It has not been possible to study lateral facies variations within the Bernbjerg Formation. The basal part of the Bernbjerg Formation on Hold with Hope has a Late Oxfordian, A. glosense Chron age based on the presence of the ammonite Amoebo- ceras ilovaiskii (J.H. Callomon and P. Alsen, personal communications 1997) and dinoflagellate cysts (Piasecki et al. 2004, this volume). In the upper part of the for- mation, dinoflagellate cysts indicate a Late Oxfordian –EarlyKimmeridgian, A. serratum – P. baylei Chronage (Piasecki et al. 2004, this volume). The basal part of the Bernbjerg Formation on Hold with Hope is dominated by organic-rich, silty, fine- grained sandstones, which are horizontally laminated or locally cross-laminated. Wave-rippled, medium- to coarse-grained sandstone beds, locally with pebbles up to 1 cm in diameter, are common. The wave rip- ples have NW–SE ripple crest orientations (Fig. 10; 234– 248 m in Fig. 5). The silty fine-grained sandstones con- tain scattered Chondrites isp. Belemnites occur locally whereas ammonites are abundant. This lower coarser- grained unit of the Bernbjerg Formation is referred to the Ugpik Ravine Member (Surlyk 2003, fig. 5). The succession above the basal part of the Bernbjerg Formation consists of structureless or horizontally lami- nated dark mudstones (Fig. 12). No macrofossils were found in the mudstones. Total organic carbon (TOC) content is about 2 wt% based on two samples. The lower boundary of the Bernbjerg Formation is not ex- posed, and the formation is erosionally overlain by Lower Cretaceous coarse-grained sandstones. The Bernbjerg Formation probably continues into the sub- surface along Gulelv. The horizontally laminated and locally cross-lami- nated silty fine-grained sandstones from the basal part of the Bernbjerg Formation reflect deposition from suspension fall-out and weak bottom currents during fair-weather conditions. Storm-wave currents most likely deposited the interbedded wave-rippled, medium to coarse-grained sandstones. The orientations of the wave ripples suggest a NW–SE-trending coastline. The facies are interpreted to have been deposited in the offshore transition to lower shoreface zone. The overlying dark mudstones are interpreted to have been deposited off- shore from suspension fall-out based on the fine grain size and dominant horizontal lamination. Palaeoenvironments and basin configuration The Jurassic succession on Hold with Hope shows a stepwise, but overall fining-upwards trend (Fig. 5) re- flecting long-term transgression. The transgression was interrupted by a major relative sea-level fall within the Late Callovian – Middle Oxfordian time interval, rep- resented by the unconformity separating the Pelion and Payer Dal Formations. The basal Jurassic sediments seem to get younger from west to east as suggested by dinoflagellate cysts indicating the Lower Callovian C. apertum Chronozone at Stensiö Plateau and the Lower Callovian P. koenigi Chronozone at Steensby Bjerg and Diener Bjerg (Fig. 2). The age difference may reflect onset of rifting and associated onlap. Alternatively, the Stensiö Plateau formed a separate fault block, which was transgressed first. The N–S-trending fault situated at Blåelv, west of Stensiö Plateau, forms the western boundary of Juras- sic sediments today (Fig. 2). The Jurassic sea, how- ever, may have extended as far west as to the Post- Devonian Main Fault, which formed the western basin boundary during the Late Permian and Triassic (Vischer 1943; Birkelund & Perch-Nielsen 1976; Stemmerik et al. 1993). This would imply that older Jurassic sedi- ments from the western part of the basin were eroded in post-Kimmeridgian time. Transport of eroded mate- rial towards the east may explain the occurrence of Cranocephalites sp., indicating the Upper Bajocian C. pompeckji Chronozone, in the Cretaceous basal con- glomerate at Steensby Bjerg. The sediment source area may, however, also have been Clavering Ø, west of the Dombjerg–Clavering Fault, which is believed to have formed a palaeo-high in Jurassic times (Vischer 1943; Stemmerik et al. 1993). Lateral facies variations within the Spath Plateau Member (Pelion Formation) indicate that palaeo-water depths decreased from west to east. This suggests a similar setting to that envisaged for the Wollaston For- GEUS Bulletin no 5.pmd 29-10-2004, 11:1467 68 land Basin where deposition took place on the W– SW-tilted hangingwalls of major fault blocks and the elevated fault block crests formed elongated islands or peninsulas to the east (Vischer 1943; Maync 1947; Donovan 1957; Surlyk 1977; Surlyk et al. 1981; Surlyk & Clemmensen 1983). The presence of the marine Pelion and Payer Dal Formations in the vicinity of the block crest excludes the occurrence of a major land area during Callovian and Middle Oxfordian time when the crest probably only formed elongated islands or submarine shoals. The Hold with Hope area is thus interpreted to have formed a narrow embayment which was open for marine circulation towards the south and, during peri- ods of high sea level, eastwards across the elevated fault block crest. Farther towards the east, the fault block was most likely limited by the continuation of the Dombjerg–Clavering Fault, which was active dur- ing the Jurassic (Maync 1947; Surlyk 1977; Stemmerik et al. 1993). The narrow head of the rift-basin occurs in an intermediate position between the Wollaston Forland and Jameson Land Basins that are situated to 100 km 20ºW 16ºW24ºW28ºW 76ºN 74ºN 72ºN Wollaston Forland Basin Hold with Hope Traill Ø Jameson Land Basin Upper shoreface Lower shoreface Offshore Inferred coastline Main direction of sediment transport Early–Middle Callovian Fig. 13. Early–Middle Callovian palaeo- geography and facies distribution in East Greenland. Based on Surlyk (1977), Engkilde & Surlyk (2003), Vosgerau et al. (2004, this volume), and new data from Hold with Hope. GEUS Bulletin no 5.pmd 29-10-2004, 11:1468 69 the north-east and south-west, respectively (Fig. 13). The Hold with Hope region seems to have formed a land area during the Late Callovian – Middle Oxfordian time interval whereas it was covered by sea during maximum flooding in Late Bajocian, Early–Middle Callovian and Late Oxfordian – Kimmeridgian times. A close comparison of the Jurassic successions in the Wollaston Forland, Hold with Hope and Jameson Land basins is hindered by limited biostratigraphic control at some levels due to the scarcity of ammo- nites and dinoflagellate cysts in the coarse sandstone facies. It is evident, however, that the Late Callovian – Middle Oxfordian hiatus in the Hold with Hope basin has not been demonstrated in the other two basins where sediments of Early–Middle Oxfordian age are well documented (Fig. 4). The minor angular unconformity between the Pelion and Payer Dal Formations suggests that the hiatus was formed by minor tilting of fault blocks and erosion of uplifted block crests perhaps combined with eustatic sea-level falls. Sea-level falls, possibly eustatic, have been suggested to take place in Late Callovian time, at the Early–Middle Oxfordian boundary and in early Late Oxfordian time (Sahagian et al. 1996) and seem to cor- respond to changes in regional sea level documented in Jameson Land (Larsen & Surlyk 2003). The dark mudstones of the Bernbjerg Formation reflect deposition in a quiet offshore environment in- dicating that the influence of basin topography was overprinted by rise in relative sea level. Fault block crests to the east were finally inundated during the Kimmeridgian. Strong fault activity occurred at the boundary be- tween the post-Kimmeridgian and pre-Barremian suc- cessions and the fault blocks originally defining the Hold with Hope basin were split into smaller blocks, a similar tectonic development to that seen in the Wolla- ston Forland Basin. Comparison with the Wollaston Forland Basin suggests that this tectonic episode took place in Volgian–Valanginian time. Summary and conclusions A new Middle–Upper Jurassic succession is described from northern Hold with Hope. The Jurassic sediments occur on the hangingwall of small fault blocks dipping towards the WSW. The sediments are locally eroded away on the uplifted block crests, whereas they in- crease in thickness down-dip on the hangingwalls. The Jurassic succession is up to 360 m thick and is referred to the Pelion, Payer Dal and Bernbjerg Formations of Early Callovian – Early Kimmeridgian age. It overlies Lower Triassic siltstones and sandstones with a sharp boundary and is overlain by Cretaceous coarse-grained sandstones with an angular unconformity. The succes- sion was deposited in a shoreface–offshore marine environment and reflects an overall transgression. The Pelion Formation is c. 190 m thick and consists of a lower sandstone unit, 30–40 m thick, overlain by a drowning surface and sandy heteroliths and sand- stones of the new Spath Plateau Member, c. 155 m thick. The lower sandstone unit spans the Lower Callovian C. apertum – P. koenigi Chronozones. It con- sists of medium to coarse-grained sandstones, which are trough cross-bedded or structureless and contain small pebbly scour-fills. The sandstones commonly form coarsening-upwards units, 6–8 m thick, the upper part of which are calcite cemented and contain abundant Diplocraterion habichi. The sandstones are interpreted to have been deposited in the middle to upper shore- face zone. The Spath Plateau Member is of late Early – Middle Callovian, P. koenigi – P. athleta Chron age based on ammonites and dinoflagellate cysts. It is domi- nated by lower–middle shoreface ripple cross-laminated sandy heteroliths and cross-bedded sandstones reflect- ing migration of 2-D and 3-D dunes in distributary channels and mouth bars associated with tidally influ- enced deltas. The Payer Dal Formation is more than 70 m thick and of Middle–Late Oxfordian, C. tenuiserratum – A. glosense Chron age. It consists of cross-bedded sand- stones and sandy heteroliths showing considerable lat- eral thickness variations and reflects progradation of tidally influenced dunes and mouth bars. It is sepa- rated from the underlying Pelion Formation by an an- gular unconformity representing a Late Callovian – Middle Oxfordian hiatus, formed by subaerial erosion related to an eustatic sea-level fall, combined with minor tiltingof fault blocks and erosion of uplifted block crests. The Bernbjerg Formation is at least 130 m thick and spans the Upper Oxfordian – Lower Kimmeridgian (A. glosense – P. baylei Chronozones). The basal part con- sists of horizontally laminated and locally cross-lami- nated silty fine-grained sandstones interbedded with thin wave-rippled medium- to coarse-grained sand- stones and is referred to the Ugpik Ravine Member. Deposition took place in the offshore transition to lower shoreface zone. The upper part of the formation con- sists of structureless or horizontally laminated dark mudstones reflecting offshore deposition in an outer shelf environment. GEUS Bulletin no 5.pmd 29-10-2004, 11:1469 70 Deposition of the Jurassic succession on Hold with Hope took place in a narrow rift-controlled embayment as indicated by the distribution of the sediments and dominating south-westwards palaeocurrent directions in the Pelion and Payer Dal Formations. Lateral facies variations in the Spath Plateau Member indicate a de- crease in palaeowater depth from west to east. The embayment was open to marine circulation to the south and probably partly to the east, where the crestal mar- gin of a slightly westwards to south-westwards tilted block formed elongated narrow islands or submarine shoals. During the deposition of the Bernbjerg Forma- tion, the influence of basin topography was overprinted by a rise in relative sea level and the fault block crest to the east was inundated. Towards the west, the Stensiö Plateau may have formed a separate block that was transgressed first, as indicated by the fact that the Pelion Formation is older at this locality than at Steensby Bjerg and Diener Bjerg. The presence of an angular unconformity between the Jurassic and Cretaceous succession shows that block rotation took place in post-Kimmeridgian – pre-Bar- remian time. During this tectonic episode, the fault block originally defining the Hold with Hope basin was split into narrower blocks. This might have taken place in the Volgian–Valanginian as suggested by com- parison with the Wollaston Forland Basin where a simi- lar tectonic event took place during this time interval. Acknowledgements The present study received support from Saga Petro- leum asa, and is a contribution to the project ‘Resources of the sedimentary basins of North and East Green- land’ supported by the Danish Research Councils. 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