Modern and early Holocene ice shelf sediment facies from Petermann Fjord and northern Nares Strait, northwest Greenland

Based on sediment cores and geophysical data collected from Petermann Fjord northern Nares Strait, NW Greenland, an Arctic ice shelf facies is presented that distinguishes sub pro environments. Sediment were sites beneath the present day Ice Tongue (PIT) in deglacial sediments of Strait with a focus understanding glacial oceanographic history over last 11,000 cal yr BP. The modern laminated devoid coarse clasts (IRD) due to strong basal melting releases debris (debris filtering) at grounding zone driven by buoyant subglacial meltwater entrained Atlantic Water. Laminated deep basin proximal gounding comprise layers fine mud formed suspension settling turbid plumes (plumites) interrupted normally graded very sand medium silt sharp contacts rip-up mud, interpreted as turbidites. An inner fjord sill limits distribution gravity flows basin, such beyond tongue largely only plumites. Bioturbation foraminiferal abundances increase distance zone. benthic species, Elphidium clavatum absent tongue, but dominant influenced environment tongue. sparse IRD PIT derives mainly englacial side valley glaciers, rock falls steep walls sea ice. We use characteristics infer past presence shelves using analyses several cruises (OD1507, HLY03, 2001LSSL, RYDER19). On bathymetric highs, bioturbated dispersed overlies 10–15 m thick, distinctly clay unit rare foraminifera which forms drape nearly uniform thickness. interpret these represent glaciomarine deposition emanating streams terminated floating shelves. layers, shifts composition (qXRD, MS XRF) faunal assemblage changes document periods ice-shelf instability sometimes, not always, coupled retreat. Our reconstruction, including shelves, begins ∼10.7 ka BP, confluent grounded Hall Basin fronted Robeson Channel shelf. breakup retreat relatively stable zones Kennedy mouth was accomplished 9.4 BP when established. This broke up reformed once prior final break 8.5 8.4 marking stream collapse, separation Greenland Innuitian sheets, opening for Arctic-Atlantic throughflow. remained until Glacier retreated ∼7.1 resilience early Holocene insolation subsurface Water advection attributed their aspect, buttressing narrow passages, high flux Sheet (GIS).