East-west cross sections of the Jurassic age San Rafael Group rocks from western Colorado to central and western Utah

1978 ◽  
Author(s):  
James Clifton Wright ◽  
Dayton Delbert Dickey
Keyword(s):  
Cross Sections ◽  
Western Colorado ◽  
San Rafael ◽  
East West

scholarly journals North-south cross sections of the Jurassic San Rafael Group in Utah and western Colorado

1978 ◽  
Author(s):  
James Clifton Wright ◽  
Dayton Delbert Dickey
Keyword(s):  
Cross Sections ◽  
Western Colorado ◽  
San Rafael

Miscellaneous cross sections of the Jurassic San Rafael Group in southern Utah

1978 ◽  
Author(s):  
James Clifton Wright ◽  
Dayton Delbert Dickey
Keyword(s):  
Cross Sections ◽  
San Rafael

scholarly journals IMP 8 magnetosheath field comparisons with models

1998 ◽  
Vol 16 (4) ◽  
pp. 376-387 ◽  
Author(s):  
Z. Kaymaz
Keyword(s):  
Magnetic Field ◽  
Interplanetary Magnetic Field ◽  
Cross Sections ◽  
Field Vector ◽  
Cross Sectional ◽  
Vector Maps ◽  
Planetary Magnetic Fields ◽  
Magnetohydrodynamic Models ◽  
The Magnetic Field ◽  
East West

Abstract. This study presents cross-sectional vector maps of the magnetic field derived from IMP 8 magnetometer in the magnetosheath at 30 Re behind the Earth. In addition the vector patterns of the magnetosheath field for northward, southward, and east-west interplanetary magnetic field (IMF) directions are qualitatively compared with those obtained from the Spreiter-Stahara gas dynamic (GD) and Fedder-Lyon magnetohydrodynamic models (MHD). The main purpose is to display the cross-sectional differences in relation to the dayside merging with different IMF directions, allowing the reader to make direct visual comparisons of the vector patterns. It is seen that for east-west IMF directions, the data-based and MHD-based patterns differ noticeably in a similar way from the GD model, presumably reflecting the influence of dayside magnetic merging of the Earth's magnetic field with the y-component of the interplanetary magnetic field. All three northward IMF cross sections show comparable field draping patterns as expected for a closed magnetosphere. For southward IMF case, on the other hand, differences between the three cross-sectional patterns are greater as seen in the field vector sizes and directions, especially closer to the magnetopause where more disturbed magnetospheric conditions are known to be exist. The data comparisons with the MHD and GD models show that the differences result from the magnetic field-flow coupling and that the effects of dayside reconnection are present in IMP 8 magnetic field measurements.Keywords. Vector maps · IMP 8 magnetometer · Inter-planetary magnetic fields

Glaciotectonics and tunnel valleys in the southeastern North Sea imaged by high-resolution multi-channel seismics

2020 ◽  
Author(s):  
Arne Lohrberg ◽  
Sebastian Krastel ◽  
Daniel Unverricht ◽  
Klaus Schwarzer
Keyword(s):  
High Resolution ◽  
North Sea ◽  
Cross Sections ◽  
Forward Direction ◽  
Subsequent Formation ◽  
Reflection Seismic ◽  
Dense Grid ◽  
Thrust Sheets ◽  
Multiple Deformation ◽  
East West

<p>Glaciotectonic disturbance of sediments and tunnel valleys are often found near the margin of former ice sheets. Hence, these landforms can be used to reconstruct the dynamics of former ice sheet margins. The direction of thrusts usually points perpendicular to the ice front. Considering heterogeneity due to local ice advances, this relation can be used to infer the regional forward direction of large ice lobes. Here, we present a dense grid of high-resolution 2D multi-channel reflection seismic data from the German sector of the southeastern North Sea imaging a buried glaciotectonic complex and tunnel valleys in unprecedented detail.</p><p>We have identified individual thrust sheets in an area of approx. 650 km² (combined with recent results of Winsemann et al. (2020)). All thrust sheets are buried and partly eroded at their top. Two major phases of thrusting with two corresponding detachment surfaces have been identified in the subsurface, of which the younger phase led to the deformation of sediments several kilometers further into the foreland. The thickness of individual thrust sheets differs between 180 and 240 m. Some thrust sheets have been cut by the subsequent formation of tunnel valleys with an overall incision direction ranging from east-west to northeast-southwest. The glaciotectonic complex is limited to its southeast by an updipping reflector, which represents the margin of a source depression.</p><p>The restauration of cross-sections shows that the thrust sheets transported sediments over more than a kilometer towards the northwest to west, which relates the formation of the thrust sheets and the source depression. The landforms are very similar to a hill-hole pair that led to the foreland thrust sheets, probably as a result of combined bulldozing and gravity spreading in the foreland of the ice margin. Their occurrence and the adjacent tunnel valleys leads us to assume that we identified the marginal position of an Elsterian ice lobe in the southeastern North Sea.</p><p>Reference:<br>Winsemann, J., Koopmann, H., Tanner, D.C., Lutz, R., Lang, J., Brandes, C., Gaedicke, C., 2020. Seismic interpretation and structural restoration of the Heligoland glaciotectonic thrust-fault complex: Implications for multiple deformation during (pre-)Elsterian to Warthian ice advances into the southern North Sea Basin. Quat. Sci. Rev. 227, 1–15. https://doi.org/10.1016/j.quascirev.2019.106068</p>

A Discussion on natural strain and geological structure - Strain patterns in the Pyrenean Chain

1976 ◽  
Vol 283 (1312) ◽  
pp. 271-280 ◽  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Horizontal Displacement ◽  
Geological Structure ◽  
Deformation Analysis ◽  
Brittle Deformation ◽  
Deformation Axis ◽  
Narrow Zone ◽  
The North ◽  
East West

The Pyrenean Chain is a deformed part of the crust, fan-shaped in cross section, in which we can define the main characteristics of the major deformation as follows: (a) East—west folds always have their axial planes nearly vertical; the B axes of these folds have gentle plunges; (b) in the domain where schistosity is present (dominent flattening), the direction of maximum apparent elongation on cleavage planes, i.e. the X deformation axis, is nearly parallel to the geometric A axis of the folds. Inside the domain of strong flattening, a very narrow zone is present (less than 2 km wide on some cross sections) bounded by discontinuities, one of the most important is the North Pyrenean fault. This narrow zone is fundamentally different from the rest of the chain: (i) here, the deformation has the highest intensity and the rocks are metamorphosed; (ii) the B axes of the folds are curved and display steep plunges; (iii) the X deformation axis is parallel to the B geometric axis. We imagine that these anomalies have been created by sinistral horizontal displacement on the North Pyrenean fault during the folding. In addition to these facts, a brittle-deformation analysis permits the drawing of deformation trajectories in the flat northern foreland up to 400 km from the chain itself.

Cretaceous (Albian–Turonian) foraminiferal biostratigraphy and paleogeography of northern Montana and southern Alberta

1988 ◽  
Vol 25 (2) ◽  
pp. 316-342 ◽  
Author(s):  
Harold R. Lang ◽  
Alan McGugan
Keyword(s):  
Cross Sections ◽  
The Arctic ◽  
Tectonic Activity ◽  
Planktonic Foraminifer ◽  
The West ◽  
Isopach Maps ◽  
Southern Alberta ◽  
International Border ◽  
North And South ◽  
East West

In Albian–Turonian time, the interior of North America was flooded by a seaway extending from the present Gulf of Mexico to the Arctic Ocean. Detailed studies of this interval north and south of the Canada – United States international border have not usually been integrated. The present foraminiferal biostratigraphic study includes a 38 000 km2 area straddling the Alberta–Montana border from the Lewis thrust in the west to the Sweetgrass Hills in the east, including the Sweetgrass Arch.Stratigraphic cross sections and isopach maps of six Albian – early Turonian stratigraphic units prepared from 57 surface and subsurface sections demonstrate that sedimentation was controlled primarily by (i) sporadic volcanism to the west and (ii) tectonic activity coincident with the present location of the Sweetgrass Arch.The occurrence of the late Cenomanian planktonic foraminifer, Rotalipora cushmani, in association with three other keeled species, suggests an east–west marine connection between the eastern Pacific and Western Interior. This interpretation is consistent with the facies model described by Kauffman, the paleogeographic model developed in the present study, reported gastropod paleozoogeographic data, and reevaluation of pelecypod and ammonite paleozoogeographic interpretations.

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