Morphological Expression of Submarine Landslides in the Accretionary Prism of the Caribbean Continental Margin of Colombia

Abstract. In northern Hispaniola, the Imbert Formation (Fm) has been interpreted as an orogenic "mélange" originally deposited as trench-fill sediments, an accretionary (subduction) complex formed above a SW-dipping subduction zone, or the sedimentary result of the early oblique collision of the Caribbean plate with the Bahama Platform in the middle Eocene. However, new stratigraphical, structural, geochemical and geochronological data from northern Hispaniola indicate that the Imbert Fm constitutes a coarsening-upward stratigraphic sequence that records the transition of the sedimentation from a pre-collisional forearc to a syn-collisional piggy-back basin. This piggy-back basin was transported on top of the Puerto Plata ophiolitic complex slab and structurally underlying accreted units of the Rio San Juan complex, as it was emplaced onto the North America continental margin units. The Imbert Fm unconformably overlies different structural levels of the Caribbean subduction-accretionary prism, including a supra-subduction zone ophiolite, and consists of three laterally discontinuous units that record the exhumation of the underlying basement. The distal turbiditic lower unit includes the latest volcanic activity of the Caribbean island arc; the more proximal turbiditic intermediate unit is moderately affected by syn-sedimentary faulting; and the upper unit is a (caotic) olistostromic unit, composed of serpentinite-rich polymictic breccias, conglomerates and sandstones, strongly deformed by syn-sedimentary faulting, slumping and sliding processes. The Imbert Fm is followed by subsidence and turbiditic deposition of the overlying El Mamey Group. The 40Ar / 39Ar plagioclase plateau ages obtained in gabbroic rocks from the Puerto Plata ophiolitic complex indicate its exhumation at ∼ 45–40 Ma (lower-to-middle Eocene), contemporaneously to the sedimentation of the overlying Imbert Fm. These cooling ages imply the uplift to the surface and submarine erosion of the complex to be the source of the ophiolitic fragments in the Imbert Fm, during of shortly after the emplacement of the intra-oceanic Caribbean island-arc onto the continental margin.

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The Imbert Formation of northern Hispaniola: a tectono-sedimentary record of arc–continent collision and ophiolite emplacement in the northern Caribbean subduction–accretionary prism

Solid Earth ◽

10.5194/se-7-11-2016 ◽

2016 ◽

Vol 7 (1) ◽

pp. 11-36 ◽

Cited By ~ 4

Author(s):

J. Escuder-Viruete ◽

Á. Suárez-Rodríguez ◽

J. Gabites ◽

A. Pérez-Estaún

Keyword(s):

Subduction Zone ◽

Continental Margin ◽

Middle Eocene ◽

Accretionary Prism ◽

Island Arc ◽

Caribbean Island ◽

Stratigraphic Sequence ◽

Oblique Collision ◽

The Caribbean ◽

Ophiolitic Complex

Abstract. In northern Hispaniola, the Imbert Formation (Fm) has been interpreted as an orogenic “mélange” originally deposited as trench-fill sediments, an accretionary (subduction) complex formed above a SW-dipping subduction zone, or the sedimentary result of the early oblique collision of the Caribbean plate with the Bahama Platform in the middle Eocene. However, new stratigraphical, structural, geochemical and geochronological data from northern Hispaniola indicate that the Imbert Fm constitutes a coarsening-upward stratigraphic sequence that records the transition of the sedimentation from a pre-collisional forearc to a syn-collisional basin. This basin was transported on top of the Puerto Plata ophiolitic complex slab and structurally underlying accreted units of the Rio San Juan complex, as it was emplaced onto the North America continental margin units.The Imbert Fm unconformably overlies different structural levels of the Caribbean subduction-accretionary prism, including a supra-subduction zone ophiolite, and consists of three laterally discontinuous units that record the exhumation of the underlying basement. The distal turbiditic lower unit includes the latest volcanic activity of the Caribbean island arc; the more proximal turbiditic intermediate unit is moderately affected by syn-sedimentary faulting; and the upper unit is a (chaotic) olistostromic unit, composed of serpentinite-rich polymictic breccias, conglomerates and sandstones, strongly deformed by syn-sedimentary faulting, slumping and sliding processes. The Imbert Fm is followed by subsidence and turbiditic deposition of the overlying El Mamey Group.The 40Ar ∕ 39Ar plagioclase plateau ages obtained in gabbroic rocks from the Puerto Plata ophiolitic complex indicate its exhumation at ∼  45–40 Ma (lower-to-middle Eocene), contemporaneously to the sedimentation of the overlying Imbert Fm. These cooling ages imply the uplift to the surface and submarine erosion of the complex to be the source of the ophiolitic fragments in the Imbert Fm, during or shortly after the emplacement of the intra-oceanic Caribbean island arc onto the continental margin.

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Redistribution of Sediments by Submarine Landslides on the Eastern Nankai Accretionary Prism

Submarine Mass Movements and Their Consequences ◽

10.1007/978-90-481-3071-9_26 ◽

2010 ◽

pp. 313-322 ◽

Cited By ~ 4

Author(s):

K. Kawamura ◽

T. Kanamatsu ◽

M. Kinoshita ◽

S. Saito ◽

T. Shibata ◽

...

Keyword(s):

Accretionary Prism ◽

Submarine Landslides

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Coastal and offshore provinces of Timor-Leste — Geophysics exploration and drilling

The Leading Edge ◽

10.1190/tle39080543.1 ◽

2020 ◽

Vol 39 (8) ◽

pp. 543-550

Author(s):

Roberto Fainstein ◽

Juvêncio De Deus Correia do Rosário ◽

Helio Casimiro Guterres ◽

Rui Pena dos Reis ◽

Luis Teófilo da Costa

Keyword(s):

Continental Margin ◽

Accretionary Prism ◽

Stratigraphic Correlation ◽

Accretionary Wedge ◽

Northern Coast ◽

Potential Field Data ◽

The North ◽

Banda Arc ◽

Timor Leste ◽

Well Data

Regional geophysics research provides for prospect assessment of Timor-Leste, part of the Southeast Asia Archipelago in a region embracing the Banda Arc, Timor Island, and the northwest Australia Gondwana continental margin edge. Timor Island is a microcontinent with several distinct tectonic provinces that developed initially by rifting and drifting away from the Australian Plate. A compressive convergence began in the Miocene whereby the continental edge of the large craton collided with the microcontinent, forming a subduction zone under the island. The bulk of Timor Island consists of a complex mélange of Tertiary, Cretaceous, Jurassic, Triassic, Permian, and volcanic features over a basal Gondwana craton. Toward the north, the offshore consists of a Tertiary minibasin facing the Banda Arc Archipelago, with volcanics interspersed onshore with the basal Gondwana pre-Permian. A prominent central overthrust nappe of Jurassic and younger layers makes up the mountains of Timor-Leste, terminating south against an accretionary wedge formed by this ongoing collision of Timor and Australia. The northern coast of the island is part of the Indonesian back arc, whereas the southern littoral onshore plus shallow waters are part of the accretionary prism. Deepwater provinces embrace the Timor Trough and the slope of the Australian continental margin being the most prospective region of Timor-Leste. Overall crust and mantle tectonic structuring of Timor-Leste is interpreted from seismic and potential field data, focusing mostly on its southern offshore geology where hydrocarbon prospectivity has been established with interpretation of regional seismic data and analyses of gravity, magnetic, and earthquake data. Well data tied to seismic provides focal points for stratigraphic correlation. Although all the known producing hydrocarbon reservoirs of the offshore are Jurassic sands, interpretation of Permian and Triassic stratigraphy provides knowledge for future prospect drilling risk assessment, both onshore and offshore.

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Morphological Variability of Submarine Mass Movements in the Tectonically–Controlled Calabro–Tyrrhenian Continental Margin (Southern Italy)

Geosciences ◽

10.3390/geosciences9010043 ◽

2019 ◽

Vol 9 (1) ◽

pp. 43 ◽

Cited By ~ 2

Author(s):

Daniele Casalbore ◽

Alessandro Bosman ◽

David Casas ◽

Francesco Chiocci ◽

Eleonora Martorelli ◽

...

Keyword(s):

High Resolution ◽

Continental Margin ◽

Large Scale ◽

Southern Italy ◽

Morphological Variability ◽

Failure Behavior ◽

Main Role ◽

Submarine Landslides ◽

Large Variability ◽

Geomorphic Features

The analysis of high resolution morpho–bathymetric data on the Calabro Tyrrhenian continental margin (Southern Italy) enabled us to identify several morphological features originated by mass–wasting processes, including shallow gullies, shelf–indenting canyons and landslides. Specifically, we focus our attention on submarine landslides occurring from the coast down to −1700 m and affecting variable areas from thousands of square meters up to few tens of square kilometers. These landslides also show a large variability of geomorphic features which seems strictly related to the physiographic/morphological domains where the landslide formed. Tectonically–controlled scarps and canyon flanks are typically characterized by several coalescent and nested landslides, with diameters ranging from hundreds to a few thousands of meters. Canyon headwalls are commonly characterized by a cauliflower shape due to an array of small (diameters of tens of meters) and coalescent scars. In all these sectors, disintegrative–like landslides dominate and are generally characterized by a marked retrogressive evolution, as demonstrated by their morphology and comparison of repeated bathymetric surveys at the canyon headwall. Only in the lower part of tectonically–controlled scarps, a few cohesive–like and isolated landslides are present, indicating the main role of slope gradients and height drop in controlling the post–failure behavior of the mobilized material. Open slopes are generally characterized by large–scale (diameters of thousands of meters) and isolated scars, with associated landslide deposits. A peculiar case is represented by the Capo Vaticano Scar Complex that affected an area of about 18 km2 and is characterized by an impressive variability of landslide morphologies, varying also at short distance. The large extent and variability of such scar complex are thought to be associated with the occurrence of a mixed contouritic–turbidite system. By integrating the high–resolution morpho–bathymetric dataset with the results of previous studies, we discuss the main factors controlling the variability in size and morphology of submarine landslides developed in a tectonically–controlled setting and provide preliminary considerations on their potential geohazard in a densely populated coastal area.

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The crustal structure in the transition from the on land fold-and-thrust belt to the offshore accretionary prism in the Taiwan arc-continent collision

10.5194/egusphere-egu2020-2846 ◽

2020 ◽

Author(s):

Joaquina Alvarez-Marrón ◽

Dennis Brown ◽

Juan Alcalde ◽

Ignacio Marzán ◽

Hao Kuo-Chen

Keyword(s):

Continental Margin ◽

Seismic Tomography ◽

Accretionary Prism ◽

Crustal Thickening ◽

Accretionary Wedge ◽

Thrust Belt ◽

Deformation Front ◽

Coast Line ◽

Transition Area ◽

Fold And Thrust Belt

The region of Taiwan is undergoing active, oblique arc-continent colision between the Luzon Arc on the Philippine Sea Plate and the continental margin of Eurasia. The Fold-and-Thrust Belt (FTB) in Taiwan passes southwards into a submarine accretionary wedge at the Manila subduction zone. The aim of this contribution is to examine how an on land FTB changes into a marine accretionary prism in the context of an oblique arc-continent collision. The Miocene pre-orogenic sediments of the continental margin are widespread in the FTB ca. 23&#176; latitude while the offshore wedge is built up dominantly by Pliocene to recent syn-orogenic sediments. In the transition area from the marine accretionary wedge ca. 21&#176; latitude to the on land FTB, the thrust wedge is climbing up the slope of the Eurasian continental margin. The deformation front is at sea floor depth of ca. 4 km in the south to less than 1 km as it reaches the coast line. Here we use the island surface geology, marine reflection seismic profiles, and seismic tomography models to construct contour maps of the basal thrust and the depth to the Moho across a transition area from near 23&#176; to near 21&#176; latitude. In this zone, the deformation front draws a convex curvature as the wedge widens from ca. 50 in the north and south, to more than 130 km near 22&#176; latitude. The basal thrust surface shows a scoop shape as its dip changes from southeast near the coast line to east southward. The basal thrust reaches over 7 km deep beneath the rear of the FTB before ramping into de basement and merging into the Chaochou fault at 10 km depth. Offshore, it shows a gentler dip from 7 km to c. 10 km depth before getting steeper towards the east below the Hengchung Ridge. The basal cuts laterally along-strike through the margin&#8217;s sedimentary cover to incorporate thicker Miocene pre-orogenic sediments onto its hanging wall as it passes from the offshore wedge to the on land FTB.In the offshore area, the Moho (we use a Vp proxy of 7.5 km/s extracted from the seismic tomography) shallows southeastward, from near 25 km depth below the shelf slope break to less than 17 km depth below the offshore wedge near 21.5&#176; latitude before it starts to deep east towards beneath the Taiwan coast. The Moho dips northeast from near 25 km depth below the coast near Kaohsiung, to near 40 depth below the rear of the FTB at 23.5&#176;, latitude. This complex morphology of the Moho may be related to the changes in crustal thickness and the obliquity of the collision. Because of this, crustal thickening is less pronounced beneath southern Taiwan where the thinner part of the margin is colliding with the arc.This research is part of project PGC2018-094227-B-I00 funded by the Spanish Research Agency from the Ministry of Science Innovation and Universities of Spain.

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