Multiphase Late Devonian to Carboniferous volcanic events in the west of Oyu Tolgoi, southeastern Mongolia: New geochronological, geochemical, and isotopic constraints on tectonic history

2020 ◽  
Vol 88 ◽  
pp. 169-184 ◽  
Author(s):  
Zejia Ji ◽  
Zhicheng Zhang ◽  
Baofu Han ◽  
Narantsetseg Tserendash
Keyword(s):  
Late Devonian ◽  
The West ◽  
Tectonic History ◽  
Volcanic Events ◽  
Isotopic Constraints

scholarly journals Geology of the Upper Jurassic to Lower Cretaceous geothermal aquifers in the West Netherlands Basin – an overview

2020 ◽  
Vol 99 ◽  
Author(s):  
Cees J.L. Willems ◽  
Andrea Vondrak ◽  
Harmen F. Mijnlieff ◽  
Marinus E. Donselaar ◽  
Bart M.M. van Kempen
Keyword(s):  
Lower Cretaceous ◽  
Cold Water ◽  
Upper Jurassic ◽  
The West ◽  
Geothermal Heat ◽  
Sequence Stratigraphic ◽  
Tectonic History ◽  
Water Breakthrough ◽  
Hydrocarbon Fields ◽  
Sedimentary Aquifer

Abstract In the past 10 years the mature hydrocarbon province the West Netherlands Basin has hosted rapidly expanding geothermal development. Upper Jurassic to Lower Cretaceous strata from which gas and oil had been produced since the 1950s became targets for geothermal exploitation. The extensive publicly available subsurface data including seismic surveys, several cores and logs from hundreds of hydrocarbon wells, combined with understanding of the geology after decades of hydrocarbon exploitation, facilitated the offtake of geothermal exploitation. Whilst the first geothermal projects proved the suitability of the permeable Upper Jurassic to Lower Cretaceous sandstones for geothermal heat production, they also made clear that much detail of the aquifer geology is not yet fully understood. The aquifer architecture varies significantly across the basin because of the syn-tectonic sedimentation. The graben fault blocks that contain the geothermal targets experienced a different tectonic history compared to the horst and pop-up structures that host the hydrocarbon fields from which most subsurface data are derived. Accurate prediction of the continuity and thickness of aquifers is a prerequisite for efficient geothermal well deployment that aims at increasing heat recovery while avoiding the risk of early cold-water breakthrough. The potential recoverable heat and the current challenges to enhance further expansion of heat exploitation from this basin are evident. This paper presents an overview of the current understanding and uncertainties of the aquifer geology of the Upper Jurassic to Lower Cretaceous strata and discusses new sequence-stratigraphic updates of the regional sedimentary aquifer architecture.

Latest Devonian–Earliest Mississippian nearshore trace-fossil assemblages from West Virginia, Pennsylvania, and Maryland

1987 ◽  
Vol 61 (5) ◽  
pp. 865-889 ◽  
Author(s):  
Thomas W. Bjerstedt
Keyword(s):  
West Virginia ◽  
Trace Fossils ◽  
Price Formation ◽  
Late Devonian ◽  
Tidal Channel ◽  
Fair Weather ◽  
The West ◽  
North Central ◽  
The North ◽  
Channel Systems

Trace fossils are used in deposystem analysis of Late Devonian–Early Mississippian nearshore facies in the north-central Appalachian Basin. These nearshore facies resulted from separate transgressions during latest Devonian (Cleveland Shale) and earliest Mississippian (Sunbury Shale) time. Emphasis is placed on a well-exposed section at Rowlesburg, West Virginia, where the Oswayo, Cussewago Sandstone, and Riddlesburg Shale Members of the Price Formation are exposed.The Oswayo Member at Rowlesburg preserves an offshore-to-lower shoreface transition in a complex of euryhaline, protected-bay, lagoon, and possible estuarine facies. Cruziana is common and occurs along with Arthrophycus, Bifungites, Chondrites, Planolites, Palaeophycus, Rhizocorallium, Rosselia, Rusophycus, and Skolithos in intensely bioturbated mudstone, siltstone, and sandstone. These lithologies were deposited below fair-weather wave base and grade upsection to upper shoreface facies comprised of thick, horizontally-laminated sandstones with thinner, burrowed mudstone interbeds. Upper shoreface traces consist of Arenicolites, Cruziana, Diplocraterion, Dimorphichnus, Planolites, Thalassinoides, and Skolithos. Skolithos “pipe rock” sandstones occur at the toe of upper shoreface facies. Eastward the Oswayo Member grades into a restricted-bay facies and finally into beach and tidal flat facies near its stratigraphic wedge-out in eastern West Virginia and western Maryland. The Cussewago Sandstone Member at Rowlesburg overlies the Oswayo and is bounded at the top by a disconformity. The Cussewago contains Arenicolites, Isopodichnus, Phycodes, Planolites, and Skolithos in upper shoreface sandstones possibly related to deposition in deltaic or tidal channel systems.Regionally, the Riddlesburg Shale records a range of euryhaline environments in shallow-shelf, open-bay, and probable estuarine facies. The Riddlesburg Shale Member at Rowlesburg is comprised of dark-grey silty shales, siltstones, and hummocky cross-stratified sandstones. Trace fossils include Bergaueria, Bifungites, Fustiglyphus?, Helminthopsis, Planolites, and Skolithos. Lithofacies of the Riddlesburg Shale in West Virginia were markedly influenced by a syndepositionally active basement feature, the West Virginia Dome. Riddlesburg-age shoreface sandstones deposited on the crest of the Dome contain apparent omission surfaces with common Rhizocorallium and Arenicolites, Cruziana?, Planolites, and Skolithos.

scholarly journals Regional seismic stratigraphic correlations of the Ross Sea: Implications for the tectonic history of the West Antarctic Rift System

2007 ◽  
Author(s):  
Robert C. Decesari ◽  
Christopher C. Sorlien ◽  
Bruce P. Luyendyk ◽  
Douglas S. Wilson ◽  
Louis Bartek ◽  
...  
Keyword(s):  
Ross Sea ◽  
Rift System ◽  
The West ◽  
West Antarctic ◽  
Tectonic History ◽  
History Of ◽  
West Antarctic Rift System ◽  
West Antarctic Rift

The youngest styliolines and nowakiids (Late Devonian) currently known from New York

1986 ◽  
Vol 60 (3) ◽  
pp. 689-700 ◽  
Author(s):  
Ellis L. Yochelson ◽  
William T. Kirchgasser
Keyword(s):  
New York ◽  
North America ◽  
Wall Structure ◽  
Eastern North America ◽  
Late Devonian ◽  
Appalachian Region ◽  
The West ◽  
First Report

This is the first report of styliolines in the Angola Shale Member of the West Falls Formation in western New York. These specimens are of late Frasnian age and are the youngest individuals known from the Appalachian Region. This upward extension of range places the extinction of styliolines in eastern North America more in accord with their time of extinction in Europe. Nowakiids have also been found in the younger Hanover Shale Member, in the upper part of the Java Formation, also of late Frasnian age. These are the youngest known nowakiids from the Appalachians. Within the limits of preservation, the external characters and wall structure of the Angola styliolines are comparable with those of older specimens. The associated rare small annulated nowakiids and homotcenids have a laminated wall structure fundamentally different from that of the styliolines.

Kinematic data on major Variscan strike-slip faults and shear zones in the Polish Sudetes, northeast Bohemian Massif

1997 ◽  
Vol 134 (5) ◽  
pp. 727-739 ◽  
Author(s):  
P. ALEKSANDROWSKI ◽  
R. KRYZA ◽  
S. MAZUR ◽  
J. ŻABA
Keyword(s):  
Shear Zone ◽  
Fault Zone ◽  
Bohemian Massif ◽  
Early Carboniferous ◽  
Shear Zones ◽  
Strike Slip ◽  
Late Carboniferous ◽  
Late Devonian ◽  
The West ◽  
West Sudetes

The still highly disputable terrane boundaries in the Sudetic segment of the Variscan belt mostly seem to follow major strike-slip faults and shear zones. Their kinematics, expected to place important constraints on the regional structural models, is discussed in some detail. The most conspicuous is the WNW–ESE Intra-Sudetic Fault Zone, separating several different structural units of the West Sudetes. It showed ductile dextral activity and, probably, displacement magnitude of the order of tens to hundreds kilometres, during late Devonian(?) to early Carboniferous times. In the late Carboniferous (to early Permian?), the sense of motion on the Intra-Sudetic Fault was reversed in a semi-brittle to brittle regime, with the left-lateral offset on the fault amounting to single kilometres. The north–south trending Niemcza and north-east–southwest Skrzynka shear zones are left-lateral, ductile features in the eastern part of the West Sudetes. Similarly oriented (northeast–southwest to NNE–SSW) regional size shear zones of as yet undetermined kinematics were discovered in boreholes under Cenozoic cover in the eastern part of the Sudetic foreland (the Niedźwiedź and Nysa-Brzeg shear zones). One of these is expected to represent the northern continuation of the major Stare Mesto Shear Zone in the Czech Republic, separating the geologically different units of the West and East Sudetes. The Rudawy Janowickie Metamorphic Unit, assumed in some reconstructions to comprise a mostly strike-slip terrane boundary, is characterized by ductile fabric developed in a thrusting regime, modified by a superimposed normal-slip extensional deformation. Thrusting-related deformational fabric was locally reoriented prior to the extensional event and shows present-day strike-slip kinematics in one of the sub-units. The Sudetic Boundary Fault, although prominent in the recent structure and topography of the region, was not active as a Variscan strike-slip fault zone. The reported data emphasize the importance of syn-orogenic strike-slip tectonics in the Sudetes. The recognized shear sense is compatible with a strike-slip model of the northeast margin of the Bohemian Massif, in which the Kaczawa and Góry Sowie Units underwent late Devonian–early Carboniferous southeastward long-distance displacement along the Intra-Sudetic Fault Zone from their hypothetical original position within the Northern Phyllite Zone and the Mid-German Crystalline High of the German Variscides, respectively, and were juxtaposed with units of different provenance southwest of the fault. The Intra-Sudetic Fault Zone, together with the Elbe Fault Zone further south, were subsequently cut in the east and their eastern segments were displaced and removed by the younger, early to late Carboniferous, NNE–SSW trending, transpressional Moldanubian–Stare Mesto Shear Zone.

Monitoring system at etna volcano during seismo-volcanic crisis of december 2018 based on multiorbits SBAS-DInSAR analysis

2020 ◽  
Author(s):  
Susi Pepe ◽  
Manuela Bonano ◽  
Raffaele Castaldo ◽  
Francesco Casu ◽  
Claudio De luca ◽  
...  
Keyword(s):  
Local Population ◽  
Deformation Pattern ◽  
Etna Volcano ◽  
The West ◽  
Eastern Flank ◽  
Deformation Velocity ◽  
Volcanic Events ◽  
Western Side ◽  
East West

<p>An intense volcano-tectonic crisis affected a part of Etna volcano from 24 to 27 December 2018; such event was analyzed and monitored by using the DInSAR technique, taking advantage from Sentinel-1 constellation and COSMO-SkyMed measurements to retrieve the observed deformation pattern.</p><p>In particular, we used Sentinel-1 datasets acquired by ascending and descending orbits by with a 6 days revisit time and with the Interferometric Wide Swath (IWS) acquisition mode, referred to as Terrain Observation with Progressive Scans (TOPS). This volcano-tectonic crisis generated an intrusion dyke with an intense eruptive activity at summit craters accompanied by explosions and lava flows, modifying also part of the volcanic edifice and  on 26 December 2018 an earthquake with M=4.9 localized on the lower part of the southeastern flank. We generated long-term deformation mean deformation velocity maps and the corresponding time series relevant to pre-event (April 2015-24 December 2018) and post-event (28 December 2018-March 2020). We exploited for the crisis two ascending and one descending orbits interferograms acquired from Sentinel-1 undergo to a multilook operation (5 and 20 pixels along the azimuth direction and range, respectively) to finally lead to a ground pixel size of about 70 by 70 meters. Furthermore, we combined ascending and descending orbits to obtain the East-West and Vertical components of the volcano edifice displacements.</p><p>The main results show that the deformation on Etna summit craters and on eastern flank of edifice astride the eruptive event, causing a vertical deformation of about 50 cm and a jump of about 40 cm on horizontal component. These evidences are confirmed by East-West interferogram, whose maximum values exceed 30 cm towards the West and 40 towards the East on the summit of the volcano. Instead In the area in correspondence of the 26 December main shock, a maximum eastward and westward displacement of 12-14 cm and 15-17 cm is observed, respectively. In general, after December 27th the velocity map vertical and horizontal show a progressive attenuation of movements over time. For the eastern flank, horizontal displacements (eastwards) until to 10 cm were achieved in the months following the seismic-volcanic events of December 2018. In the region south-west of the Fiandaca structure, affected by the 4.9 MW earthquake, there is an almost stationary trend of the movement in the post-event period with a small movement of 1.5 cm towards the west in the last month. Finally, even the deformation of the area around the Elachea island currently shows a positive stationary trend (towards the east). On the western side, the trend of post-event displacement showed increases compared to the period preceding the event, although with generally smaller entities than on the eastern side. he progressive Tattenuation of the extent of the movement towards the west with time reaching about 7 cm in the last year is highlighted.</p><p>This analysis allowed to Italian Civil Protection to follow the evolution in the last two years of volcano - tectonic crises and the scientific community to take relevant decisions about the level of emergency for the local population.</p>

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