Regional tectonics derived from gravity gradients

AbstractThe average anisotropy beneath Anatolia is very strong and is well constrained by shear-wave splitting measurements. However, the vertical layering of anisotropy and the contribution of each layer to the overall pattern is still an open question. Here, we construct anisotropic phase-velocity maps of fundamental-mode Rayleigh waves for the Anatolia region using ambient noise seismology and records from several regional seismic stations. We find that the anisotropy patterns in the crust, lithosphere and asthenosphere beneath Anatolia have limited amplitudes and are generally consistent with regional tectonics and mantle processes dominated by the collision between Eurasia and Arabia and the Aegean/Anatolian subduction system. The anisotropy of these layers in the crust and upper mantle are, however, not consistent with the strong average anisotropy measured in this area. We therefore suggest that the main contribution to overall anisotropy likely originates from a deep and highly anisotropic region round the mantle transition zone.

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Erratum to “Origin of the Strait of Çanakkale (Dardanelles): regional tectonics and the Mediterranean–Marmara incursion” [Marine Geology 164 (2000) 139–156]

Marine Geology ◽

10.1016/s0025-3227(00)00046-3 ◽

2000 ◽

Vol 167 (1-2) ◽

pp. 189-190 ◽

Cited By ~ 2

Author(s):

C Yaltırak ◽

B Alpar ◽

M Sakınç ◽

H Yüce

Keyword(s):

Marine Geology ◽

The Mediterranean ◽

Regional Tectonics

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Benthic foraminiferal response to relative sea-level changes in the Maastrichtian–Danian succession at the Dakhla Oasis, Western Desert, Egypt

Geological Magazine ◽

10.1017/s0016756816001023 ◽

2016 ◽

Vol 155 (3) ◽

pp. 729-746 ◽

Cited By ~ 9

Author(s):

SHERIF FAROUK ◽

SREEPAT JAIN

Keyword(s):

Sea Level ◽

Western Desert ◽

Level Curve ◽

Sea Level Changes ◽

Low Oxygen ◽

Benthic Environment ◽

Oxygen Conditions ◽

Early Paleocene ◽

Dakhla Oasis ◽

Regional Tectonics

AbstractThe Maastrichtian–Danian benthic foraminiferal diversity and assemblages through sequence stratigraphy were studied at Dakhla Oasis, Egypt. Benthic foraminifera numbers (BFN), high-flux species and characteristic benthic foraminiferal species and genera distribution are also incorporated to assess palaeobathymetry, palaeoenvironment and palaeoproductivity. All these proxies are then taken together to construct a sea-level curve and interpreted in terms of regional tectonics, climate and eustasy. Data suggest a remarkably highly equitable benthic environment deposited in a brackish littoral and/or marsh setting with moderate (?) to low oxygen conditions and reduced salinity (oligotrophic), possibly due to increased precipitation and terrestrial runoff. The interrupted dominance of calcareous forms and high-organic-flux species suggests occasional marine incursions and high palaeoproductivity, due to local upwelling. The inferred sea-level curve replicates the global eustatic curve and suggests that the curve is more influenced by the prevailing climate and global eustasy rather than by regional tectonics. The post-Cretaceous–Palaeogene boundary displays improvement in the environment in terms of diversity and number of species and specimens, with a marked reduction in the abundance of high-organic-flux species during early Paleocene (Danian) time, indicating a shift from a more mesotrophic open marine environment to much reduced oligotrophic conditions.

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Possible evidence for contemporary doming of the Adirondack Mountains, New York, and suggested implications for regional tectonics and seismicity

Tectonophysics ◽

10.1016/0040-1951(75)90142-0 ◽

1975 ◽

Vol 29 (1-4) ◽

pp. 169-181 ◽

Cited By ~ 42

Author(s):

Y.W. Isachsen

Keyword(s):

New York ◽

Adirondack Mountains ◽

Regional Tectonics

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Tectonique synsedimentaire d'age cretace superieur en Tunisie nord orientale; blocs bascules et reorganisation des aires de subsidence

BSGF - Earth Sciences Bulletin ◽

10.2113/171.4.431 ◽

2000 ◽

Vol 171 (4) ◽

pp. 431-440 ◽

Cited By ~ 9

Author(s):

Lahcen Boutib ◽

Fetheddine Melki ◽

Fouad Zargouni

Keyword(s):

Structural Analysis ◽

Upper Cretaceous ◽

Tectonic Activity ◽

Normal Faults ◽

Half Graben ◽

Combined Movements ◽

Basin Floor ◽

Tunisian Atlas ◽

Facies Variation ◽

Regional Tectonics

Abstract Structural analysis of late Cretaceous sequences from the northeastern Tunisian Atlas, led to conclude on an active basin floor instability. Regional tectonics resulted in tilted blocks with a subsidence reorganization, since the Campanian time. These structural movements are controlled both by N140 and N100-120 trending faults. The Turonian-Coniacian and Santonian sequences display lateral thickness and facies variation, due to tectonic activity at that time. During Campanian-Maastrichtian, a reorganization of the main subsidence areas occurred, the early Senonian basins, have been sealed and closed and new half graben basins developed on area which constituted previously palaeohigh structures. These syndepositional deformations are characterized by frequent slumps, synsedimentary tilting materials, sealed normal faults and progressive low angle unconformities. These tilted blocks combined to a subsidence axis migration were induced by a NE-SW trending extensional regime. This extension which affects the Tunisian margin during the Upper Cretaceous, is related to the Tethyan and Mesogean rifting phase which resulted from the combined movements of the African and European plates.

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