Showing papers by "Karsten Piepjohn published in 2000"

Eocene Compressive Deformation in Arctic Canada, N orth Greenland and Svalbard and Its Plate Teetonic Causes

Abstract: The compressive deformation in the Eurekau fold belt of Canada as weil as in the Wcst-Spitsbergen Fold-and-thrust bell is related to northward movement of the Greenland plate between anomalies 24 and 13, During this period, spreading systems Wand E of Greenland, eonverging at a RRR triplejunetion S of Greenland, were active simultaneously. It is proposed that sinistral strike-slip movement in Nares Strait occurred before this period, when spreading occurred in the Baffin Bay system W of Greenland only and the entire Eurasian plate (with Greenland attached) moved to the NE,

The Svalbardian–Ellesmerian deformation of the Old Red Sandstone and the pre-Devonian basement in NW Spitsbergen (Svalbard)

Abstract: Abstract In NW Spitsbergen, the Late Silurian to Late Devonian infill of an Old Red Sandstone (ORS) basin was affected by west-vergent folding and west-directed thrusting during the Early Carboniferous (Tournaisian) Svalbardian deformation. The brittle, predominantly compressional structures of the Svalbardian Fold-and-Thrust Belt are concentrated along at least five narrow, more or less north-south-trending zones. Three zones are exposed in the Devonian infill of the ORS basin. The involvement of the post-Caledonian ?Late Silurian to Earliest Devonian Viggobreen weathering zone and deposits Early Devonian in two thrust zones within the basement of the western basin margin indicates that the Svalbardian deformation also affected the basement areas along the west coast of NW Spitsbergen. Structures of the Svalbardian Fold-and-Thrust Belt are exposed within an area at least 100 km wide between the Billefjorden Fault Zone in the east and the west coast of NW Spitsbergen. Therefore, the Svalbardian deformation represents a much more important fold belt than previously recognized. On the basis of the timing, the large extent and the orientation of the fold-and-thrust zones, the Svalbardian Fold-and-Thrust Belt appears to represent the eastern continuation of the Ellesmerian Fold Belt in North Greenland and the Canadian Arctic Archipelago.

New data on the age of the uppermost ORS and the lowermost post-ORS strata in Dickson Land (Spitsbergen) and implications for the age of the Svalbardian deformation

Abstract: Abstract In NW Spitsbergen, the infill of a large Old Red Sandstone (ORS) basin was affected by the Svalbardian deformation shortly after the sedimentation of the uppermost ORS units. In the Billefjorden area, along the eastern margin of the basin, folded and thrustfaulted Devonian deposits are unconformably overlain by undeformed Carboniferous clastic sediments and platform carbonate deposits. To re-examine the age of the Svalbardian deformation, samples for palynological investigations were taken from the youngest deformed ORS strata and the oldest post-Svalbardian sediments. The results of palynological investigations show that the folded and thrust-faulted uppermost ORS unit, the Plantekløfta member of the Mimerdalen Formation (Andrée Land Group), is Late Famennian in age. The lowermost undeformed and unconformably overlying post-ORS unit, the Triungen member of the Hørbyebreen Formation (Billefjorden Group), is ?Late Tournaisian to Viséan but not Famennian in age. Thus, the compressional west-directed folding and thrusting of the Svalbardian deformation took place after Late Famennian and before Late Tournaisian time.

Involvement of a Tertiary Foreland Basin in the Eurekan Foldbelt Deformation, NW Coast of Kane Basin, Ellesmere Island, Canada

Abstract: Summary: Along the NW eoast of Kane Basin (Ellesmere Island), a flatlying eonglomerate sueeession of a Tertiary foreland basin is overthrust by thiek Early Paleozoie sediments during the Tertial')' Eurekan deformation. In the sourhern study area between Franklin Pierce Bay and Dobbin Bay, Cambrian to Silurian sediments are thrust over the Tertiary basin along the Parrish Glaeier anel Cape Hawks thrusts. In front of the Parrish Glacier Thrust, Ordovician/Silurian, Cretaceous and Tertiary deposits are involved into a stack of several thrust sheets along dctachments characterized by flat-ramp gcometries, Due to erosion, sornc of the thrust sheets are cxposcd in klippcn and comprisc a tectonic inversion of the rock units. The N-dipping Allman Bay Reverse Fault on the peninsula between Franklin Pierce Bay anel Allman Bay rcprcscnts the southernmost exposed Eurekan strueture in the Dobbin Bay area. The transport directions are predominantly towards SSE and S. In the northern study area at Cape Lawrcnce, Cambrian and younger sedimcnts are thrust over the Tertiary basin along the WNW-dipping Rawlings Bay Thrust Zone. Between the Cambrian of the hanging wall and the Tertiary of the footwall, folded Ordovician evaporites and carbonates are imbricated in the thrust zone. The thick Tertiary eonglomerate beds below the Rawlings Bay Thrust Zone arc also affected by intense Eurekan shortening which is charaeterized by flat-lying detachments, folds and triangle structures. Hcre, the transport directions are to the E and ESE. In the study areas, the Eurekan deformation is characterized by compression with SSE- to E-directed tectonic transport towards the basement bloeks of the GreenIand-Canadian shield SE of Narcs Strait and S of Prineess Marie Bay. Only at Cape Lawrencc, a largc-scale, SE-vergent anticlinal­ synelinal pair and a NW-dipping reverse fault in the Tertiary eonglomerate eould be related to sinistral strike-slip movements along Nares Strait after deposition of the eonglomerate and prior to the Eurekan comprcssion along the Rawlings Bay Thrust Zone.