Cretaceous Oceanic Red Beds (CORBs) in the Austrian Eastern Alps: Passive-Margin vs. Active-Margin Depositional Settings

2009 ◽  
pp. 73-88 ◽  
Author(s):  
MICHAEL WAGREICH ◽  
STEFANIE NEUHUBER ◽  
HANS EGGER ◽  
INES WENDLER ◽  
ROBERT SCOTT ◽  
...  
Keyword(s):  
Eastern Alps ◽  
Passive Margin ◽  
Red Beds ◽  
Active Margin ◽  
Depositional Settings

Comparison of turbidite facies associations in modern passive-margin Mississippi fan with ancient active-margin fans

1988 ◽  
Vol 58 (1) ◽  
pp. 63-77 ◽  
Author(s):  
G. Shanmugam ◽  
R.J. Moiola ◽  
J.G. McPherson ◽  
S. O'Connell
Keyword(s):  
Passive Margin ◽  
Active Margin ◽  
Facies Associations

scholarly journals The Wechsel Gneiss Complex of Eastern Alps: an Ediacaran to Cambrian continental arc and its Early Proterozoic hinterland

2020 ◽  
Vol 113 (1) ◽  
Author(s):  
Franz Neubauer ◽  
Yongjiang Liu ◽  
Ruihong Chang ◽  
Sihua Yuan ◽  
Shengyao Yu ◽  
...  
Keyword(s):  
Oceanic Lithosphere ◽  
Eastern Alps ◽  
Detrital Zircons ◽  
Passive Margin ◽  
Low Grade ◽  
Metasedimentary Rocks ◽  
Gneiss Complex ◽  
Continental Arc ◽  
Nappe Complex ◽  
Nearby Source

AbstractMany metamorphosed basement complexes in the Alps are polymetamorphic and their origin and geological history may only be deciphered by detailed geochronology on the different members including oceanic elements like ophiolites, arc successions, and continental passive margin successions. Here we present a case study on the Lower Austroalpine Variegated Wechsel Gneiss Complex and the overlying low-grade metamorphosed Wechsel Phyllite Unit at the eastern margin of Alps. The Wechsel Gneiss Complexes are known to have been overprinted by Devonian metamorphism, and both units were affected by Late Cretaceous greenschist facies metamorphism. New U–Pb zircon ages reveal evidence for two stages of continental arc-like magmatism at 500–520 Ma and 550–570 Ma in the Variegated Wechsel Gneiss Complex. An age of ca. 510 Ma of detrital zircons in metasedimentary rocks also constrain the maximum age of metasedimentary rocks, which is younger than Middle Cambrian. The overlying Wechsel Phyllite Unit is younger than 450 Ma (Late Ordovician) and seems to have formed by denudation of the underlying Variegated Wechsel Gneiss Complex. We speculate on potential relationships of the continental arc-type magmatism of the Variegated Wechsel Gneiss Complex and potential oceanic lithosphere (Speik complex) of Prototethyan affinity, which is also preserved in the Austroalpine nappe complex. The abundant, nearly uniform 2.1 Ga- and ca. 2.5 Ma-age signature of detrital zircons in metasediments (paragneiss, quartzite) of the Variegated Wechsel Gneiss Complex calls for Lower Proterozoic continental crust in the nearby source showing the close relationship to northern Gondwana prominent in West Africa and Amazonia.

scholarly journals A two-dimensional model of the methane cycle in a sedimentary accretionary wedge

2012 ◽  
Vol 9 (8) ◽  
pp. 3323-3336 ◽  
Author(s):  
D. E. Archer ◽  
B. A. Buffett
Keyword(s):  
Heat Flux ◽  
Passive Margin ◽  
Model Description ◽  
Accretionary Wedge ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Methane Cycle ◽  
Active Margin ◽  
Two Dimensional Model ◽  
The Impact

Abstract. A two-dimensional model of sediment column geophysics and geochemistry has been adapted to the problem of an accretionary wedge formation, patterned after the margin of the Juan de Fuca plate as it subducts under the North American plate. Much of the model description is given in a companion paper about the application of the model to an idealized passive margin setting; here we build on that formulation to simulate the impact of the sediment deformation, as it approaches the subduction zone, on the methane cycle. The active margin configuration of the model shares sensitivities with the passive margin configuration, in that sensitivities to organic carbon deposition and respiration kinetics, and to vertical bubble transport and redissolution in the sediment, are stronger than the sensitivity to ocean temperature. The active margin simulation shows a complex sensitivity of hydrate inventory to plate subduction velocity, with results depending strongly on the geothermal heat flux. In low heat-flux conditions, the model produces a larger inventory of hydrate per meter of coastline in the passive margin than active margin configurations. However, the local hydrate concentrations, as pore volume saturation, are higher in the active setting than in the passive, as generally observed in the field.

scholarly journals Neoproterozoic-paleozoic evolution of the Drina formation (Drina-Ivanjica entity)

2018 ◽  
Vol 79 (2) ◽  
pp. 57-68 ◽  
Author(s):  
Darko Spahic ◽  
Bojan Glavas-Trbic ◽  
Slavica Djajic ◽  
Tivadar Gaudenyi
Keyword(s):  
Lower Devonian ◽  
Amphibolite Facies ◽  
Passive Margin ◽  
Early Paleozoic ◽  
Active Margin ◽  
Lower Paleozoic ◽  
Margin Setting ◽  
Felsic Volcanism

This paper addresses a Drina-Ivanjica basement member, Drina Formation, characterized by ? controversial Neoproterozoic to Carboniferous age. The Drina Formation is also informally referred to as the ?Lower Drina Formation? and the ?Upper Drina Formation? including the Golija Formation as a conditional analog unit of the latter. A review of the biostratigraphic, sedimentary and paleogeographic constraints identified Drina Formation (Inner Dinarides) as a migrated crustal segment derived from a marginal section of northern Gondwana, being, however, of Neoproterozoic-Early Paleozoic age. The presence of arenites, pelites, conglomerates, scarce limestones, basic (sub)volcanics and tuffs of the volcano-sedimentary Drina Formation metamorphosed up to greenschist and locally up to amphibolite facies, coupled with the absence of felsic volcanism implies a passive margin setting. Considering the age, such environment was probably associated with the perplexed Lower Paleozoic Avalonian-Cadomian arc, situated along the former north Gondwanan active margin. More precisely, the Drina Formation originated from a depositional junction between the Gondwana sediment supplier (Sahara metacraton) and Cadomian arc. A comparison with the regional Early Paleozoic succession of the ?Kucaj Unit? (eastern Serbia) yields the absence of typical anchimetamorphic Silurian to Lower Devonian deep-marine fossil-bearing succession. The volcano-sedimentary passive margin system of Drina Formation is overlain by a late Variscan convergencerelated voluminous clastic sequence allocated as the Golija Formation.

scholarly journals A two-dimensional model of the methane cycle in a sedimentary accretionary wedge

2012 ◽  
Vol 9 (3) ◽  
pp. 2967-3002 ◽  
Author(s):  
D. E. Archer ◽  
B. A. Buffett
Keyword(s):  
Companion Paper ◽  
Passive Margin ◽  
North American Plate ◽  
Model Description ◽  
Accretionary Wedge ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Methane Cycle ◽  
Active Margin ◽  
Two Dimensional Model

Abstract. A two-dimensional model of sediment column geophysics and geochemistry has been adapted to the problem of an accretionary wedge formation, patterned after the margin of the Juan de Fuca plate as it subducts under the North American plate. Much of the model description was given in a companion paper about application of the model to a passive margin setting; here we build on that formulation to simulate the deformation of the sediment wedge as it approaches the subduction zone. The active margin configuration of the model shares sensitivities with the passive margin configuration, in that sensitivities to organic carbon deposition and respiration kinetics, and to vertical bubble transport and redissolution in the sediment, are stronger than the sensitivity to ocean temperature. The active margin simulation also shows a sensitivity to plate subduction velocity, with higher plate velocities producing less hydrate per meter of coastline than slower velocities or the passive margin configuration. However, the local hydrate concentrations, as pore volume saturation, are higher in the active setting than the passive, as generally observed in the field.

Tectonic and geomorphic controls on the distribution of submarine landslides across active and passive margins, eastern New Zealand

2019 ◽  
Vol 500 (1) ◽  
pp. 477-494 ◽  
Author(s):  
S. J. Watson ◽  
J. J. Mountjoy ◽  
G. J. Crutchley
Keyword(s):  
New Zealand ◽  
Slope Failure ◽  
Submarine Landslide ◽  
Passive Margin ◽  
Continental Margins ◽  
Submarine Landslides ◽  
Mass Wasting ◽  
Active Margin ◽  
Passive Margins ◽  
Marine Habitats

AbstractSubmarine landslides occur on continental margins globally and can have devastating consequences for marine habitats, offshore infrastructure and coastal communities due to potential tsunamigenesis. Therefore, understanding landslide magnitude and distribution is central to marine and coastal hazard planning.We present the first submarine landslide database for the eastern margin of New Zealand comprising >2200 landslides occurring in water depths from c. 300–4000 m. Landslides are more prevalent and, on average, larger on the active margin compared with the passive margin. We attribute higher concentrations of landslides on the active margin to tectonic processes including uplift and oversteepening, faulting and seamount subduction. Submarine landslide scars are concentrated around canyon systems and close to canyon thalwegs. This suggests that not only does mass wasting play a major role in canyon evolution, but also that canyon-forming processes may provide preconditioning factors for slope failure.Results of this study offer unique insights into the spatial distribution, magnitude and morphology of submarine landslides across different geological settings, providing a better understanding of the causative factors for mass wasting in New Zealand and around the world.

The Pre-Pan-African rifting of Saghro (Anti-Atlas, Morocco): example of the middle Neoproterozoic Basin of Boumalne

2002 ◽  
Vol 173 (1) ◽  
pp. 25-35 ◽  
Author(s):  
Abdelilah Fekkak ◽  
André Pouclet ◽  
Lakhlifi Badra
Keyword(s):  
Continental Margin ◽  
Detrital Zircons ◽  
Passive Margin ◽  
Lava Flows ◽  
Active Margin ◽  
Volcanic Arc ◽  
Chemical Signature ◽  
Pan African ◽  
Back Arc ◽  
Oceanic Domain

Abstract In the Anti-Atlas, the Boumalne basin includes 3,000 m of Middle Neoproterozoic sediments. It consists of turbiditic deposits folded during the major Pan-African event ca 685 Ma. A syn-sedimentary basaltic pile of lava flows is interbedded in the upper part of the lower formation. These lavas show an initial rift tholeiite (IRT) chemical signature. Petrographical analysis of sediments and typology of detrital zircons indicate a continental margin sedimentation, without any volcano-sedimentary supply from a close volcanic arc. It is concluded that the Boumalne Basin formed in a continental passive margin evolving from an intracontinental rift. This interpretation differs clearly from that of a back-arc basin which is commonly accepted. Hence, the opening of this basin is related to the pre-Pan-African Saghro rift synchronous to the Central Anti-Atlas oceanization, and not to the demise of this oceanic domain along an active margin.

Guadalupian (Permian) onset of subduction zone volcanism and geodynamic turnover from passive- to active-margin tectonics in southeast China

2019 ◽  
Vol 132 (1-2) ◽  
pp. 130-148 ◽  
Author(s):  
Feng-Qi Zhang ◽  
Hong-Xiang Wu ◽  
Yildirim Dilek ◽  
Wei Zhang ◽  
Kong-Yang Zhu ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
South China ◽  
Carbonate Platform ◽  
Passive Margin ◽  
Magma Source ◽  
South China Block ◽  
The South ◽  
Active Margin ◽  
Topographic High

Abstract New stratigraphic, geochemical, and geochronological data from the late Paleozoic depositional record in Anhui Province, China, signal the onset of active-margin magmatism in East Asia. Chert-shale sequences of the Gufeng Formation are part of a Carboniferous–Permian carbonate platform that developed along the passive margin of the South China block. Thin tuffaceous interlayers in these sequences represent distal ash deposits, marking discrete volcanic events. Sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon dating of the stratigraphically bottom and near-top tuffaceous interlayers has revealed crystallization ages of 270 Ma and 264 Ma, respectively, constraining the time span of subaerial eruptions to ∼6 m.y. during the Guadalupian Epoch. High SiO2 and Al2O3 contents, enrichments in large ion lithophile and light rare earth elements, and depletion patterns of high field strength and heavy rare earth elements indicate a calc-alkaline magma source in an arc setting for the origin of these volcanic tuff deposits. Detrital zircon geochronology of sandstones in the overlying Longtan Formation shows two prominent age populations of 290–250 Ma and 1910–1800 Ma. The former age cluster overlaps with the tightly constrained zircon ages obtained from the Gufeng Formation. The latter age group is compatible with the known magmatic-metamorphic ages from Cathaysia in the South China block, and it points to the existence of a NE-SW–trending topographic high as a major sediment source. We interpret this topographic high and silicic volcanism to represent an Andean-type active margin, developed above a north-dipping paleo-Pacific slab. Our tightly constrained Guadalupian eruption ages indicate the inception of magmatic arc construction and mark a major switch from passive- to active-margin tectonics along SE Asia.

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