Stratigraphy of the Silurian turbidite sequence of North Greenland

Abstract

A new lithostratigraphic scheme is erected for the Silurian deep-water clastic rocks of North Greenland, from Washington Land in the west to Kronprins Christian Land in the east. All Silurian clastic rocks are included in the Peary Land Group and were deposited in upper to lower slope, submarine fan and basin plain environments. All age determinations are based on graptolites. Ordovician faunas are of North American aspect whilst Silurian faunas are cosmopolitan. Therefore, series and stage definitions in the Ordovician follow American terminology whereas in the Silurian standard international terminology is used. Eight formations and six members are included in the Peary Land Group, which extends from the latest Ordovician (Cincinnatian) to the latest Silurian (Pridoli). Lithostratigraphic units include: Sydgletscher Formation (new) composed of basinal, extremely thick, structureless sandstone beds and black mudstones – Lower Llandovery; Cape Schuchert Formation composed of upper slope mudstones, calcarenites and cherts – Middle Llandovery to lower Upper Llandovery; Lafayette Bugt Formation composed of upper to lower slope mudstones and resedimented limestone conglomerates - Middle Llandovery to Ludlow; Merqujoq Formation (new), a middle to outer fan and basinal sandstone dominated turbidite sequence of 'classical flysch' appearance - uppermost Ordovician (Cincinnatian) to uppermost Llandovery; Citronens Fjord Member (new), a base-of-slope resedimented limestone conglomerate, shale and thin-bedded siltstone and mudstone turbidite sequence – ?Middle Llandovery to Upper Llandovery; Freja Fjord Member (new), an isolated base-of-slope resedimented limestone conglomerate – Upper Llandovery; Wulff Land Formation (new), a lower slope to basin plain black mudstone and thin-bedded fine sandstone and siltstone turbidite sequence – Upper Llandovery to Lower Ludlow; Repulse Havn Member (new), a lower slope to basin plain sequence of thin-bedded mudstone and siltstone turbidites – Lower to Middle Ludlow; Thors Fjord Member (new), a lower slope to basin plain sequence of black mudstones with fine siltstone and sandstone turbidite units – Upper Llandovery to Middle Wenlock; Lauge Koch Land Formation (new), an outer fan and basinal sandstone and siltstone turbidite sequence of 'classical flysch' appearance – Upper Llandovery to Lower Ludlow; Profilfjeldet Member (new), a faulted, folded and cleaved sandstone turbidite and mudstone sequence in Kronprins Christian Land – Upper Llandovery to Middle Wenlock; Nordkronen Formation (new), a sequence of chert pebble conglomerates, pebbly sandstones and sandstones deposited in a base-of-slope and submarine fan environment – ?Middle Wenlock to ?Lower Ludlow; Hendrik ø Member (new) which represents the western distal wedge of the Nordkronen Formation – ?Lower Ludlow; Chester Bjerg Formation (new) composed of basinal laminated mudstones and fine turbiditic sandstones – ?Lower Ludlow to Upper Pridoli..