Transition from a Passive Continental Margin to an Active Margin Documented by Time-Facies Profiles and Geohistory Diagrams: ABSTRACT

AAPG Bulletin ◽  
1988 ◽  
Vol 72 ◽  
Author(s):  
Jeroen A. M. Kenter, John J. G. Rey
Keyword(s):  
Continental Margin ◽  
Passive Continental Margin ◽  
Active Margin

scholarly journals Hydrogeological dissimilarity of geodynamically different terranes

2021 ◽  
Vol 44 (2) ◽  
pp. 134-140
Author(s):  
V. E. Glotov
Keyword(s):  
Continental Margin ◽  
Sandy Loam ◽  
Active Continental Margin ◽  
Passive Continental Margin ◽  
Coarse Grained ◽  
Active Margin ◽  
Water Abundance ◽  
Fine Grained ◽  
Weathering Processes

The article presents and analyzes the data on ground waters of active (suprapermafrost) and hindered (subpermafrost) water exchange of geodynamically different terrains in order to prove the hydrogeological importance of their historical and tectonic characteristics. On the example of Trans-Polar Chukotka it is shown that, under suprapermafrost conditions, the ubiquitous eluvial-deluvial nappes are the most water-abundant on the terrane – a fragment of the passive continental margin, whereas they are the least water-abundant on the terrains of the active margin. Hydrogeological situation changes under subpermafrost conditions: more permeable and water-retaining rocks compose the terranes of the active margin. These differences are associated with the level of rock tectonic decompaction and, accordingly, with different intensity of weathering processes in the terrane rocks of different geodynamic origin in suprapermafrost and subpermafrost conditions. The hypergenesis zone on the terranes of the passive continental margin features coarse-grained rock weathering products accumulated in relatively calm geological and historical environments, the aggregate is sandy. The terranes of the active margin, which underwent long-term subvertical and subhorizontal displacements contain more fine-grained weathering products; the aggregate includes sandy loam and clay sand. Since the permafrost strata in both Trans-Polar Chukotka and Eastern Siberia is greater than the depth of hypergene transformations, the terranes of the active continental margin, the rocks of which were impacted by tectonic decompaction processes, mainly of a strike-slip and thrust nature, feature greater water abundance in subpermafrost conditions.

scholarly journals Dynamics and age of formation of the Seram-Ambon ophiolites (Central Indonesia)

2003 ◽  
Vol 174 (6) ◽  
pp. 529-543 ◽  
Author(s):  
Christophe Monnier ◽  
Jacques Girardeau ◽  
Hariady Permana ◽  
Jean-Pierre Rehault ◽  
Hervé Bellon ◽  
...  
Keyword(s):  
Continental Crust ◽  
Continental Margin ◽  
Passive Continental Margin ◽  
Early Miocene ◽  
Geochemical Data ◽  
Active Margin ◽  
Short Span ◽  
Group 2 ◽  
Type 3

Abstract The Seram-Ambon ophiolitic series comprise peridotites, websterites, gabbros and lavas. Petro-geochemical data show that the peridotites are weakly depleted rocks, except for the rare Cpx-free harzburgites. They underwent a sub-solidus metamorphic re-equilibration in the plagioclase field. The associated websterites and gabbros display various chemical features, allowing to define 3 types of websterites and 2 groups of gabbros. They have mostly BAB characteristics (presence of negative anomalies in Nb, Zr, Ti and Y), except the group 2 gabbros which have N-MORB features and the type 3 websterites which bear adakitic affinities. Lavas also display a variety of compositions, including high-Mg IAT and Mg-rich BABB with sub-alkaline affinities. Both IAT and BABB display high Th/Nb ratios which support an origin close to a continental crust environment. Our 20 to 15 Ma 40K/40Ar ages calculated for the BABB and 15-9 Ma for the IAT show that the basin and arc formed in a very short span of time, before their obduction 9–7 Ma ago [Linthout et al., 1997]. Considering the paleogeographic situation in the Miocene [Haile, 1979 ; Haile, 1981] and our data, we propose that the Seram-Ambon ophiolites formed during the early Miocene in a small, short-lived (10 Ma), transtensive basin bordered on its east by an active margin and on its western part by a passive continental margin over which it was later obducted towards the SW direction.

Paleozoic formations of the Northeast margin of the European platform

2006 ◽  
Author(s):  
A. I. Eliseev ◽  
◽  
A. I. Antoshkina ◽  
V. A. Saldin ◽  
N. Yu. Nikulova ◽  
...  
Keyword(s):  
Continental Margin ◽  
Sedimentary Basins ◽  
Passive Continental Margin ◽  
European Continent ◽  
History Of ◽  
Geodynamic Reconstructions

Paleozoic sedimentary basins of the northeast European Platform is a component of large megabasin of the northeast passive continental margin of the European continent in the Paleozoic. The establishment of a connection between a paleodynamic history of a basin and its sedimentary formations types, which are the most reliable indicators of geodynamic conditions, is one of the primary problems of modern lithology. Reliable indicators at geodynamic reconstructions are genetically predetermined by laterial and vertical lines of the sedimentary formations. Formations and lithological complexes being the brightest indicators of the paleodynamic regimes change of the basin have been considered formations lines of the passive continental margin of the westuralian type during the Paleozoic.

scholarly journals Tectono-thermal evolution of Oman's Mesozoic passive continental margin under the obducting Semail Ophiolite: a case study Jebel Akhdar, Oman

2018 ◽  
Author(s):  
Arne Grobe ◽  
Christoph von Hagke ◽  
Ralf Littke ◽  
István Dunkl ◽  
Franziska Wübbeler ◽  
...  
Keyword(s):  
Fluid Inclusion ◽  
Continental Margin ◽  
Thermal Evolution ◽  
Carbonate Platform ◽  
Passive Continental Margin ◽  
Passive Margin ◽  
Temperature Evolution ◽  
Thermal Maturity ◽  
Solid Bitumen ◽  
Shear Sense

Abstract. The Mesozoic sequences of the Oman Mountains experienced only weak post-obduction overprint and deformation, thus they offer a unique natural laboratory to study obduction. We present a study of the pressure and temperature evolution in the passive continental margin under the Oman Ophiolite, using numerical basin models calibrated with thermal maturity data, fluid inclusion thermometry and low-temperature thermochronology. Thermal maturity data from the Adam Foothills constrain burial in the foredeep moving in front of the advancing nappes to be at least 4 km. Peak temperature evolution in the carbonate platform under the ophiolite is only weakly dependent on the temperature of the overriding nappes which have cooled during transport from the oceanic subduction zone to emplacement. Fluid-inclusion thermometry yields pressure-corrected homogenization temperatures of 225 to 266 °C for veins formed during progressing burial, 296–364 °C for veins related to peak burial and 184 to 213 °C for veins associated with late-stage strike-slip faulting. In contrast, the overlying Hawasina nappes have not been heated above c. 170 ºC, as witnessed by only partial resetting of the zircon (U-Th)/He thermochronometer. In combination with independently determined temperatures from solid bitumen reflectance, we infer that the fluid inclusions of peak-burial-related veins formed at minimum pressures of 225–285 MPa. This implies that the rocks of the future Jebel Akhdar Dome were buried under 8–10 km of ophiolite on top of 2 km of sedimentary nappes, which is in agreement with thermal maturity data of solid bitumen reflectance and Raman spectroscopy. Burial of the passive margin under the ophiolite results in sub-lithostatic pore pressures, in agreement with observations on veins formed in dilatant fractures in the carbonates. We infer that overpressure is induced by rapid burial under the ophiolite nappes. Obduction-related tilt of the passive margin in combination with overpressure in the passive margin caused fluid migration towards the south in front of the nappes. Exhumation of the Jebel Akhdar as indicated by our zircon (U-Th)/He data, integrated with existing data, started as early as the late Cretaceous to early Cenozoic, linked with extension along a major listric shear zone with top-to-NNE shear sense, together with an early phase of extensional dome formation. The carbonate platform and obducted nappes of the whole Jebel Akhdar cooled together below c. 170 °C between 50 and 40 Ma, before the final stage of anticline formation.

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