Baffin Bay Composite Tectono-Sedimentary Element

2021 ◽  
pp. M57-2016-7
Author(s):  
Paul C. Knutz ◽  
Ulrik Gregersen ◽  
Christopher Harrison ◽  
Thomas A. Brent ◽  
John R. Hopper ◽  
...  
Keyword(s):  
Structural Complexity ◽  
Large Data ◽  
Source Rocks ◽  
Sea Floor ◽  
Baffin Bay ◽  
Early Oligocene ◽  
Oceanic Basin ◽  
Late Paleocene ◽  
Transitional Crust ◽  
Sea Floor Spreading

AbstractBaffin Bay formed as a result of continental extension during the Cretaceous, which was followed by sea floor spreading and associated plate drift during the early to middle Cenozoic. Formation of an oceanic basin in the central part of Baffin Bay may have begun from about 62 Ma in tandem with Labrador Sea opening but the early spreading phase is controversial. Plate-kinematic models suggests that from Late Paleocene the direction of sea floor spreading changed to N-S generating strike-slip movements along the transform lineaments, e.g. the Ungava Fault Zone and the Bower Fracture Zone, and structural complexity along the margins of Baffin Bay. The Baffin Bay Composite Tectono-Sedimentary Element (CTSE) represents a 3-7 km thick Cenozoic sedimentary and volcanic succession that has deposited over oceanic and rifted continental crust since active seafloor spreading began. The CTSE is subdivided into 5 seismic mega-units that have been identified and mapped using a regional seismic grid tied to wells and core sites. Thick clastic wedges of likely Late Paleocene to Early Oligocene age (mega-units E and D2) were deposited within basins floored by newly formed oceanic crust, transitional crust, volcanic extrusives and former continental rift basins undergoing subsidence. The middle-late Cenozoic is characterized by fluvial-deltaic sedimentary systems, hemipelagic strata and aggradational sediment bodies deposited under the influenced of ocean currents (mega-units D1, C and B). The late Pliocene to Pleistocene interval (mega-unit A) displays major shelf margin progradation associated with ice-sheet advance-retreat cycles resulting in accumulation of trough-mouth fans and mass-wasting deposits products in the oceanic basin. The Baffin Bay CTSE has not produced discoveries although a hydrocarbon potential may be associated with Paleocene source rocks. Recent data have improved the geological understanding of Baffin Bay although large data and knowledge gaps remain.

Icelandia

2021 ◽  
Author(s):  
Gillian Foulger ◽  
Laurent Gernigon ◽  
Laurent Geoffroy
Keyword(s):  
Continental Crust ◽  
Structural Complexity ◽  
Ne Atlantic ◽  
Sea Floor ◽  
Passive Margins ◽  
The North ◽  
The Pacific ◽  
Ne Atlantic Ocean ◽  
Sea Floor Spreading ◽  
North And South

<p>The NE Atlantic formed by complex, piecemeal breakup of Pangea in an environment of structural complexity. North of the present-day latitude of Iceland the ocean opened by southward propagation of the Aegir ridge. South of the present-day latitude of Iceland breakup occurred along the proto-Reykjanes ridge which formed laterally offset by ~ 100 km from the Aegir ridge to the north. Neither of these new breakup axes were able to propagate across the east-westerly striking Caledonian frontal thrust region which formed a strong barrier ~ 400 km wide. As a result, while sea-floor spreading widened the NE Atlantic, the Caledonian front region could only keep pace by diffuse stretching of the continental crust, which formed the aseismic Greenland-Iceland-Faroe ridge. The magmatic rate there was similar to that of the ridges to the north and south and so the stretched continental crust is now blanketed by thick mafic flows and intrusions. The NE Atlantic also contains a magma-inflated microcontinent – the Jan Mayen Microplate Complex, and an unknown but probably large amount of stretched continental crust blanketed by seaward-dipping reflectors in the passive margins of Norway and Greenland. The NE Atlantic thus contains voluminous continental crust in diverse forms and settings. If even a small portion of the sunken continental material contiguous with the Greenland-Iceland-Faroe ridge is included the area exceeds a million square kilometers, an arbitrary threshold suggested to designate a sunken continent. We have called this region Icelandia. The conditions and processes that funneled large quantities of continental crust into the NE Atlantic ocean are common elsewhere. This includes much of the North and South Atlantic oceans including both the seaboards and the deep oceans. Nor are such processes and outcomes confined to oceans bordered by passive margins. They are also found around the Pacific rims where subduction is in progress. Indeed, these conditions and processes likely are generic to essentially all the world's oceans and are potentially also informed by observations from intracontinental extensional regions and land-locked seas.</p>

Seismicity of the Baffin Bay region

1974 ◽  
Vol 64 (1) ◽  
pp. 87-98
Author(s):  
Anthony Qamar
Keyword(s):  
Upper Mantle ◽  
Baffin Island ◽  
Sea Floor ◽  
Baffin Bay ◽  
Hypocenter Determination ◽  
Joint Hypocenter Determination ◽  
Glacial Rebound ◽  
Sea Floor Spreading ◽  
Linear Trends ◽  
Northeast Coast

abstract Twenty-eight earthquakes in the Baffin Bay region have been relocated using the method of Joint Hypocenter Determination. The revised locations indicate two parallel, linear trends, one along the northeast coast of Baffin Island and the other in the western part of Baffin Bay. The seismicity does not appear to be controlled by glacial rebound but may be a remnant of sea-floor spreading which occurred 40 to 60 m.y. ago. Early P arrivals at near seismograph stations (Δ < 20°) can be explained by a high-velocity (8.5 km/sec) upper mantle in the Baffin region.

scholarly journals Post mid-Cretaceous inversion tectonics in the Danish Central Graben – regionally synchronous tectonic events?

2002 ◽  
Vol 49 ◽  
pp. 129-144
Author(s):  
Ole Valdemar Vejbæk
Keyword(s):  
Stress Field ◽  
Eastern Alps ◽  
Upper Jurassic ◽  
Normal Faults ◽  
Sea Floor ◽  
Early Oligocene ◽  
Tectonic Events ◽  
Structural Style ◽  
Reverse Faulting ◽  
Sea Floor Spreading

Structural analysis of the Upper Cretaceous to Palaeogene succession in the Danish Central Graben suggests continuous inversion heralded in the Late Hauterivian and continuing into Palaeogene times. The following phases of increased intensity are identified: 1) latest Santonian, 2) Mid Campanian, 3) late Maastrichtian, 4) Late Paleocene – Eocene, and 5) Early Oligocene. Phases 1 through 3 are Sub-Hercynian, phase 4 is Laramide, and phase 5 is Pyrenean according to Alpine Orogen nomenclature. A temporal change in structural style is noted from early inversion confined to narrow zones associated with reverse faulting along pre-existing normal faults to late inversion dominated by gentle basinwide flexuring and folding. Inversion phases in the Danish Central Graben seem to be synchronous with inversion phases along the Sorgenfrei-Tornquist Zone. The location of inversion is generally spatially linked to Upper Jurassic – Lower Cretaceous depocentres, whereas older depocentres generally have remained intact. The origin of the compressional stress field is generally based on suggested compressional stresses transmitted into the foreland from the Alpine Orogen. In the Sub-Hercynian phase, orogenic compression dominated the Eastern Alps and Northern Carpathians to produce a likely NW oriented compression. However, structures in Denmark rather suggest a transpressional environment resulting from NNE–SSW compression. Furthermore, transmission of Alpine orogenic stresses into the foreland commenced in the Turonian, a considerable time after the Late Hauterivian and later inversion precursors. Ridge-push forces transmitted from sea-floor spreading south of the Charlie-Gibbs fracture zone, particularly from the Goban Spur SW of Ireland, acting in conjunction with Alpine orogenic stresses are suggested as the cause for the stress field.

scholarly journals Cenozoic evolution of the Vietnamese coastal margin

2007 ◽  
Vol 13 ◽  
pp. 73-76
Author(s):  
Michael B.W. Fyhn ◽  
Lars Henrik Nielsen ◽  
Lars Ole Boldreel
Keyword(s):  
Source Rocks ◽  
Sea Floor ◽  
Southern Song ◽  
Potential Source ◽  
Fundamental Understanding ◽  
Geological Evolution ◽  
Coastal Margin ◽  
Early Neogene ◽  
Climatic Record ◽  
Sea Floor Spreading

A series of Cenozoic basins fringes the Vietnamese coastal margin, often characterised by more than 10 km of sedimentary infill (Fig. 1). Greater parts of the margin are still in an early explorational state, although significant petroleum production has taken place in all but the southern Song Hong and the Phu Khanh Basins. This has increased the need for a fundamental understanding of the processes behind the formation of the basins, including analyses of potential source rocks. The basins fringing the Indochina Block provide excellent evidence of the geological evolution of the region, and the basin geometries reflect the collision of India and Eurasia and the late Cenozoic uplift of south Indochina (Rangin et al. 1995a; Fyhn et al. in press). In addition, the basins provide evidence of regional Palaeogene rifting and subsequent Late Palaeogene through Early Neogene sea-floor spreading in the South China Sea. Apart from the regional Cenozoic tectonic record, the basins contain a high-resolution climatic record of South-East Asia due to the high depositional rates, changing depositional styles and large hinterland of the basin (Clift et al. 2004).

New geophysical evidence for sea-floor spreading in central Baffin Bay

1979 ◽  
Vol 16 (11) ◽  
pp. 2122-2135 ◽  
Author(s):  
H. R. Jackson ◽  
C. E. Keen ◽  
R. K. H. Falconer ◽  
K. P. Appleton
Keyword(s):  
Magnetic Anomaly ◽  
Crustal Structure ◽  
Magnetic Anomalies ◽  
Geophysical Data ◽  
Plate Motion ◽  
Labrador Sea ◽  
Sea Floor ◽  
Baffin Bay ◽  
Spreading Rates ◽  
Sea Floor Spreading

Geophysical data collected during a detailed survey in Baffin Bay have shown that lineated magnetic anomalies trending north-northwest occupy the deep central region. These anomalies exhibit maximum amplitudes of about 300 nT and can be modelled by a 1-km thick magnetic source layer divided into blocks of normal and reversed polarity. The magnetizations required are comparable with those of oceanic basalts. A striking feature of the gravity field is a 20 mGal gravity low, about 20 km wide, which runs through the centre of the bay with approximately the same trend as the magnetic lineations. The gravity low is associated with a change in crustal structure measured from seismic refraction data and sometimes with a deepening of the sediment-basement interface, reminiscent of a median valley. These results suggest that the magnetic anomalies were produced by sea-floor spreading and that the gravity low marks an extinct spreading centre in Baffin Bay. Comparisons of the magnetic anomaly profiles with a model profile computed for magnetic anomalies 13–24 (38 to 60 Ma), show good correlation between the observed and computed anomalies in the time period represented by anomalies 13–21, with slow spreading rates of about 0.3–0.4 cm yr−1 perpendicular to the spreading axis. These results are in reasonable agreement with magnetic anomaly identifications and spreading rates deduced from geophysical data in the Labrador Sea. The direction of plate motion in Baffin Bay is not well defined from the data, but the Labrador Sea data require plate motions at a highly oblique angle to the spreading centre in the bay. Peculiarities of the postulated spreading centre, including the change in crustal structure beneath the gravity low along its strike from south to north, and the decrease in coherence and amplitude of the magnetic anomalies immediately north of the survey area, may be the result of these very low spreading rates, oblique spreading and changes in spreading direction, or the proximity of this area to the junction with a possible major transform fault through the Nares Strait.

Burial History Reconstruction of the Appalachian Basin in Kentucky, West Virginia, Pennsylvania, and New York, Using 1D Petroleum System Models

2019 ◽  
Vol 56 (4) ◽  
pp. 365-396
Author(s):  
Debra Higley ◽  
Catherine Enomoto
Keyword(s):  
New York ◽  
Vitrinite Reflectance ◽  
Structural Complexity ◽  
Appalachian Basin ◽  
Source Rocks ◽  
Burial History ◽  
Gas Generation ◽  
Deep Basin ◽  
Utica Shale ◽  
Wet Gas

Nine 1D burial history models were built across the Appalachian basin to reconstruct the burial, erosional, and thermal maturation histories of contained petroleum source rocks. Models were calibrated to measured downhole temperatures, and to vitrinite reflectance (% Ro) data for Devonian through Pennsylvanian source rocks. The highest levels of thermal maturity in petroleum source rocks are within and proximal to the Rome trough in the deep basin, which are also within the confluence of increased structural complexity and associated faulting, overpressured Devonian shales, and thick intervals of salt in the underlying Silurian Salina Group. Models incorporate minor erosion from 260 to 140 million years ago (Ma) that allows for extended burial and heating of underlying strata. Two modeled times of increased erosion, from 140 to 90 Ma and 23 to 5.3 Ma, are followed by lesser erosion from 5.3 Ma to Present. Absent strata are mainly Permian shales and sandstone; thickness of these removed layers increased from about 6200 ft (1890 m) west of the Rome trough to as much as 9650 ft (2940 m) within the trough. The onset of oil generation based on 0.6% Ro ranges from 387 to 306 Ma for the Utica Shale, and 359 to 282 Ma for Middle Devonian to basal Mississippian shales. The ~1.2% Ro onset of wet gas generation ranges from 360 to 281 Ma in the Utica Shale, and 298 to 150 Ma for Devonian to lowermost Mississippian shales.

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