The structural evolution of the Halten Terrace, offshore Mid‐Norway: extensional fault growth and strain localisation in a multi‐layer brittle–ductile system
61
Citation
36
Reference
10
Related Paper
Citation Trend
Abstract:
ABSTRACT Tectonic subsidence in rift basins is often characterised by an initial period of slow subsidence (‘rift initiation’) followed by a period of more rapid subsidence (‘rift climax’). Previous work shows that the transition from rift initiation to rift climax can be explained by interactions between the stress fields of growing faults. Despite the prevalence of evaporites throughout the geological record, and the likelihood that the presence of a regionally extensive evaporite layer will introduce an important, sub‐horizontal rheological heterogeneity into the upper crust, there have been few studies that document the impact of salt on the localisation of extensional strain in rift basins. Here, we use well‐calibrated three‐dimensional seismic reflection data to constrain the distribution and timing of fault activity during Early Jurassic–Earliest Cretaceous rifting in the Åsgard area, Halten Terrace, offshore Mid‐Norway. Permo‐Triassic basement rocks are overlain by a thick sequence of interbedded halite, anhydrite and mudstone. Our results show that rift initiation during the Early Jurassic was characterised by distributed deformation along blind faults within the basement, and by localised deformation along the major Smørbukk and Trestakk faults within the cover. Rift climax and the end of rifting showed continued deformation along the Smørbukk and Trestakk faults, together with initiation of new extensional faults oblique to the main basement trends. We propose that these new faults developed in response to salt movement and/or gravity sliding on the evaporite layer above the tilted basement fault blocks. Rapid strain localisation within the post‐salt cover sequence at the onset of rifting is consistent with previous experimental studies that show strain localisation is favoured by the presence of a weak viscous substrate beneath a brittle overburden.Keywords:
Basement
ABSTRACT The Permo‐Carboniferous to Eocene Sverdrup Basin in Canada's Arctic Archipelago is strongly influenced by evaporite diapirism. However, salt structures within the basin have not been extensively investigated recently due to their remote location. This study includes the interpretation of legacy seismic reflection and borehole data to characterize the geometry of selected evaporite domes, and 1D backstripping of wells to investigate tectonic and sedimentary influences on diapirism. Extensional rift‐structures appear to have played a significant role in the formation of evaporite domes by triggering and directing salt movement. Diapirism was initiated by at least the Middle Triassic and continued to develop during the Mesozoic. Differential loading of salt on opposing east–west dome margins led to their present day asymmetric geometries. Diapir growth rates in the Mesozoic were closely linked to the rate of sedimentation and influenced by regional tectonism.
Archipelago
Salt tectonics
Salt dome
Cite
Citations (26)
Cite
Citations (86)
Abstract In the Okinawa Trough, a number of mud diapirs were observed by the seismic datasets from several different cruises. In this paper, based on the seismic profiles, we separated three different types of mud diapirs according to their configuration. All the mud diapirs are associated with free gas or gas hydrates, indicating that the mud diapirs could sever good migration pathways for free gas migrating upwards. Mud diapirs are distributed in the middle and south of the Okinawa Trough. Most of them are located to the south of the Miyako Fault zone. The triggering mechanisms were discussed in a large scale, which suggests the mud diapirs might be triggered by the collision between the Eurasian Plate and the northward subducting Philippine Luzon arc. The distribution of mud diapirs was mainly controlled by the compression during the Late Miocene and the Miyako Fault zone. Copyright © 2016 John Wiley & Sons, Ltd.
Trough (economics)
Mud volcano
Seismic zone
Striation
Cite
Citations (19)
Several authors have reported intrusive gypsum in northeastern Mexico. Salt diapirism also has been inferred. Recent evidence from cores indicates that the complete sequence of evaporites behaved as a mobile unit in response to tight folding. The salt (Jurassic) has a steeply dipping planar fabric in both Sierra del Fraile, where gypsum diapirism already has been documented, and in Sierra de Minas Viejas. The salt in Sierra de Minas Viejas is abnormally thick. It seems reasonable to conclude on this basis that Minas Viejas is also a true diapir. Because of the large scale of the mobility, however, it is of no great consequence whether or not actual piercement has occurred.
Cite
Citations (8)
This paper presents the results of comprehensive mineralogical and petrographic studies conducted on evaporite rocks of the Zechstein (Upper Permian) period, extracted from boreholes drilled in the Mogilno diapir.Based on the research results, the occurrence of rock salts, potash-magnesium salts (kieseritic sylvinites), clayey salts, zubers, and anhydrites was identi ed.Those formations were assigned to cyclothems PZ-3 and PZ-2.No presence of evaporites belonging to cyclothems PZ-1 and PZ-4 were discovered.The recognized rocks were mainly composed of halite, sylvine, kieserite and anhydrite.Smaller quantities of polyhalite, kainite, carbonates and clayey minerals were also found.A number of accessory minerals were identi ed, with their salt rock contents from several to about several tens of ppm Key words: Upper Permian in Poland, Zechstein evaporites,
Lithostratigraphy
Cite
Citations (8)
BADENIAN EVAPORITE EVOLUTION AND METHANE ENTRAPMENT IN THE TRANSYLVANIAN BASIN Constantin Pene1, Octavian Coltoi2, Stefan Grigorescu2 1University of Bucharest, Faculty of Geology and Geophysics, 6 Traian Vuia Str., Bucharest, Romania 2Geological Institute of Romania, 1 Caransebes Str., 70124-RO, Bucharest, Romania Summary Transylvanian Basin is the main producer of methane in Romania. The correlation of data shows that at least during of the Lower to Middle Badenian in Transylvanian Basin and Carpathian Foredeep was a unique sedimentary basin, isolated from Central Parathetys and Mediterranean. The Badenian salt in the Transylvanian Basin has almost continuously development in average thickness of 400m. The top of the salt layer is highly undulating, while the base is nearly horizontal. The salt shapes has been different: in the central part there are pillows, layers and piercements; in east and west, salt flowing created the salt diapirs and salt wall. The salt movement created large dome-shape of the overlying deposits that represent excellent traps for the biogenic methane entrapment. The aim of this paper is to investigate the Badenian evaporites evolution we used a model of an elastic plate overlying a viscous fluid to understand the causes that created zones with different intensity of the diapirism.
Salt dome
Salt tectonics
Cite
Citations (0)
Salt water
Salt tectonics
Cite
Citations (0)
Basement
Salt tectonics
Cite
Citations (0)
The Sivas Basin in Central Anatolia is possibly the world’s finest open-air museum of salt tectonics structures. It is an elongated Oligo-Miocene sag basin that developed in an orogenic context above the Neotethys suture zone. A mid-Oligocene quiet period during convergence of the Arabian and Eurasian plates allowed the deposition of a thick sequence of evaporites. Erosion of the Taurus Mountains shed clastic sediments northwards over the evaporitic basin. Sediments and deformation propagated from the south, forming mini-basins and associated evaporite diapirs and walls. Following this quiet period, compression resumed in the early Miocene, enhancing the formation of gypsum overhangs and allochtonous sheets. The Sivas outcrops expose classic salt tectonics geometries associated with the development of diapirs: halokinetic sedimentary sequences along diapir walls, welds and evaporite sheets or canopies, minibasins, and overturned minibasin wings (overturned edges of minibasins). These exposures are some of the finest field analogues for classical petroleum provinces controlled by salt tectonics such as the Gulf of Mexico and offshore Angola. We illustrate seismic-scale structures and, in the vicinity of the evaporite bodies, interesting analogues for drilled structures where seismic data do not provide an image.
Salt tectonics
Outcrop
Cite
Citations (54)