Upslope‐climbing shelf‐edge clinoforms and the stepwise evolution of the northern European glaciation (lower Pleistocene Eridanos Delta system, U.K. North Sea): When sediment supply overwhelms accommodation

Abstract

Clinoforms are basinward‐dipping and accreting palaeo‐bathymetric profiles that record palaeo‐environmental conditions and processes; thus, clinothems represent natural palaeo‐archives. Here, we document shelf‐edge scale clinoform sets which prograded through the entire width of an epicontinental marine basin (ca. 400 km), eventually encroaching onto the opposite basin flank, where they started to prograde upslope and landward, in defiance of gravity (“upslope‐climbing clinoforms”). The giant westward‐prograding Eridanos muddy shelf‐edge clinothem originated from the Baltic hinterland in the Oligocene and achieved maximum regression in the Early Pleistocene, on the UK Central Graben (CG) and Mid North Sea High (MNSH), after crossing the whole North Sea mesopelagic depocentre and causing near complete basin infill. Here we integrate well and seismic data through the MNSH and CG and examine the Eridanos final heyday and demise, identifying five clinothem complexes (A1, A2, A3, B and C) and six depositional sequence boundaries (SB1 to SB6) in the Miocene‐Recent section. Tectonic and climatic events drove the recent evolution of this system. Early Pleistocene climate cooling, in particular, resulted in a stepwise increase in sediment supply. This climaxed in the earliest Calabrian, following a likely Eburonian eustatic fall (=SB3) when the Eridanos clastic wedge was restructured from a 100–300 m thick compound shelf‐edge and delta system to a “hybrid” shelf‐edge delta at sequence boundary SB3 (ca. 1.75 Ma). In the ca. 40 kyr that followed SB3, a progradation rate peak (>1,000 m/kyr) is associated with clinoforms starting to accrete upslope, onto the east‐dipping slope between CG and MNSH. This “upslope‐climbing clinoform” phase was quickly followed by the maximum regression and final retreat of the Eridanos system in the Early Calabrian (=SB4), likely as the result of climate‐driven changes in the Baltic hinterland and/or delta auto‐retreat. To our knowledge, this contributions represents the first documentation of “upslope‐climbing clinoforms” recorded in the stratigraphic record.

Ephemeral rollover points and clinothem evolution in the modern Po Delta based on repeated bathymetric surveys

“…Delta scale clinothems, characterized by tens of metres of relief (Patruno & Helland‐Hansen, ), are depositional elements fundamental in understanding ancient physiographic settings (e.g. Patruno et al, ; Pellegrini et al, ; Rovere, Pellegrini, Chiggiato, Campiani, & Trincardi, ; Steel & Olsen, ), the evolution of modern coasts (e.g. Coleman, ; Correggiari et al, ; Correggiari et al, ; Törnqvist, Bick, González, Borg, & Jong, ), and the main processes governing their formation (Burgess, Steel, Granjeon, Hampson, & Dalrymple, ; Gerber et al, ; Muto & Steel, ; Swenson et al, ).…”

Salt‐induced crestal faults control the formation of Quaternary tunnel valleys in the southern North Sea

“…2018; Patruno et al . 2020). Clinoforms are replaced by horizontal parallel reflections upwards and in the up‐dip direction.…”

Exploring the reservoir potential of Lower Cretaceous Clinoforms in the Fingerdjupet Subbasin, Norwegian Barents Sea

“…Late Barremian reworking of possible sand‐sized sediments associated with the BrU is a possible mechanism for reservoir development in delta‐scale clinoforms in the S2b Sequence. Seismic stratigraphy suggests that the S2b‐age delta‐scale clinoform sets prograded outward across a previously tilted substrate (c.f., Patruno et al, ).…”