The cenozoic sediments cover of western central Atlantic oceanic floor was cored at about 5 000 m depth, close to the deformation front of the Barbados Accretionary Prism. Good preservation of sedimentary structures and high recovery rate allowed the recognition and study of hemipelagic calcareous or siliceous clays and muds, with or without interbedded airfall volcanic ash beds, and with or without interbedded coarser deposits coming from lateral inputs. The latters are either calcareous fine-grained turbidites coming from local shallower oceanic areas, or terrigenous and calcareous (more hypothetical) contourites (reworking turbidites) related to bottom currents running along the South-America margin. Fluid-escape veinstructures, related to dewatering process - upward, vertical to almost horizontal advection - were identified, especially in relation with the beginning of offscraping stress in early Miocene incipient décollementhorizon. Twenty-four color print photos of splitted cores are presented; the macroscopic features they show are commented and discussed. La couverture sédimentaire cénozoïque du plancher océanique de l'Atlantique Central occidental a été carottée à environ 5000 m de profondeur, à proximité du front de déformation du prisme d'accrétion de la Barbade. Une bonne préservation des structures sédimentaires et un taux de récupération élevé ont permis la reconnaissance et l'étude d'argilites et shales hémipélagiques, calcaires ou siliceuses, localement intercalées de lits de cendres volcaniques, et auxquelles s'ajoutent des niveaux plus grossiers attribués à des apports latéraux. Ces derniers consistent, soit en turbidites calcareuses à grain fin provenant de hauts-fonds océaniques proches, soit en (plus hypothétiques) contourites calcareuses et terrigènes (remaniant des turbidites) attribuées à l'activité de courants profonds longeant la marge sud-américaine. Des veinesd'échappement de fluides - advection verticale ascendante, à presque horizontale - ont été identifiées, particulièrement en relation avec la naissance des contraintes d' offscrapingau sein des sédiments Miocène inférieur, siège du futur décollement. Vingt-quatre photographies couleurs de carottes sont présentées; les structures macroscopiques qu'elles montrent sont commentées et discutées.

A 23-day marine geophysical expedition in the summer of 1996 revealed a previously unidentified strike-slip fault zone within 60–100 km of the densely populated northern coast of Puerto Rico. The purpose of the expedition, which was held aboard the U.S. research vessel Maurice Ewing, was to map the northeastern portion of the North America Caribbean plate boundary. The 3000-km-long North America-Caribbean plate boundary stretches from Guatemala to the Lesser Antilles arc. The dominantly left-lateral strike-slip boundary accommodates slow (1–2.6 cm/yr) eastward motion of the Caribbean plate relative to North America. Distributed interplate motion in the region generates large earthquakes (Figure 1, inset). In 1976, an M 7.5 left-lateral, strike-slip earthquake in Guatemala killed approximately 23,000 people and left a quarter of the nation's population homeless.

Detailed studies of the chemical composition of interstitial waters in the sediments obtained along a drill hole transect across the accretionary prism of the Northern Barbados Ridge have revealed a complex set of processes: (1) In Plio-Pleistocene volcanic ash-bearing sediments increased concentrations of dissolved calcium and decreases in dissolved magnesium are the result of volcanic ash alteration; (2) below the decollement large concentration increases in dissolved calcium, accompanied by large decreases in sodium as well as a granual decrease in dissolved magnesium, suggest exchange of these constituents with the deeper seated rocks of layer 2 of the oceanic crust; (3) low chloride concentrations, particularly associated with the decollement zone separating the converging plates and underthrusted sandstones, and also with recent faults in the accretionary complex, suggest advective transport of low chlorinity waters from deeper within the accretionary complex. In and below the decollement zone elevated concentrations of methane of thermogenic origin have been measured.

Research Article| November 01, 1989 Upslope deposition of extremely distal turbidites: An example from the Tiburon Rise, west-central Atlantic James Dolan; James Dolan 1U.S. Geological Survey, M.S. 999, Menlo Park, California 94025 Search for other works by this author on: GSW Google Scholar Christian Beck; Christian Beck 2Département des Géosciences, Université de Savoie, B.P. 1104, 77011 Cambery Cedex, France Search for other works by this author on: GSW Google Scholar Yujiro Ogawa Yujiro Ogawa 3Department of Geology, Kyushu University 33, Hakozaki, Fukuoka 812, Japan Search for other works by this author on: GSW Google Scholar Author and Article Information James Dolan 1U.S. Geological Survey, M.S. 999, Menlo Park, California 94025 Christian Beck 2Département des Géosciences, Université de Savoie, B.P. 1104, 77011 Cambery Cedex, France Yujiro Ogawa 3Department of Geology, Kyushu University 33, Hakozaki, Fukuoka 812, Japan Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1989) 17 (11): 990–994. https://doi.org/10.1130/0091-7613(1989)017<0990:UDOEDT>2.3.CO;2 Article history First Online: 02 Jun 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation James Dolan, Christian Beck, Yujiro Ogawa; Upslope deposition of extremely distal turbidites: An example from the Tiburon Rise, west-central Atlantic. Geology 1989;; 17 (11): 990–994. doi: https://doi.org/10.1130/0091-7613(1989)017<0990:UDOEDT>2.3.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract Terrigenous silt and sand turbidites recovered from the crest of the Tiburon Rise in the west-central Atlantic represent an unprecedented example of upslope turbidite deposition in an extremely distal setting. These Eocene-Oligocene beds, which were derived from South America more than 1000 km to the southeast, were probably deposited by extremely thick (>1500 m) turbidity currents that flowed parallel to the southern margin of the rise. We suggest that flow thickness was the dominant control on deposition of these beds, rather than true upslope flow. This interpretation points out the importance of local bathymetry on the behavior of even extremely distal turbidity currents. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

The cenozoic sediments cover of western central Atlantic oceanic floor was cored at about 5 000 m depth, close to the deformation front of the Barbados Accretionary Prism. Good preservation of sedimentary structures and high recovery rate allowed the recognition and study of hemipelagic calcareous or siliceous clays and muds, with or without interbedded airfall volcanic ash beds, and with or without interbedded coarser deposits coming from lateral inputs. The latters are either calcareous fine-grained turbidites coming from local shallower oceanic areas, or terrigenous and calcareous (more hypothetical) contourites (reworking turbidites) related to bottom currents running along the South-America margin. Fluid-escape veinstructures, related to dewatering process - upward, vertical to almost horizontal advection - were identified, especially in relation with the beginning of offscraping stress in early Miocene incipient décollementhorizon. Twenty-four color print photos of splitted cores are presented; the macroscopic features they show are commented and discussed.

Other| January 01, 1988 Anatomie et physiologie d'un prisme d'accretion; premiers resultats des forages du complexe de la ride de la Barbade, Leg ODP 110 C. Beck; C. Beck Author Univ. Lille I, Lab. Dynam. Sediment. Struct., Villeneuve d'Ascq 59655, France Search for other works by this author on: GSW Google Scholar G. Blanc; G. Blanc Author Search for other works by this author on: GSW Google Scholar A. Mascle; A. Mascle Author Search for other works by this author on: GSW Google Scholar J. C. Moore; J. C. Moore Author Search for other works by this author on: GSW Google Scholar E. Taylor; E. Taylor Author Search for other works by this author on: GSW Google Scholar F. Alvarez; F. Alvarez Author Search for other works by this author on: GSW Google Scholar Patrick Andreieff; Patrick Andreieff Author Search for other works by this author on: GSW Google Scholar R. Barnes; R. Barnes Author Search for other works by this author on: GSW Google Scholar J. Behrmann; J. Behrmann Author Search for other works by this author on: GSW Google Scholar K. Brown; K. Brown Author Search for other works by this author on: GSW Google Scholar M. Clark; M. Clark Author Search for other works by this author on: GSW Google Scholar J. Dolan; J. Dolan Author Search for other works by this author on: GSW Google Scholar A. T. Fisher; A. T. Fisher Author Search for other works by this author on: GSW Google Scholar J. Gieskes; J. Gieskes Author Search for other works by this author on: GSW Google Scholar M. Hounslow; M. Hounslow Author Search for other works by this author on: GSW Google Scholar P. McLellan; P. McLellan Author Search for other works by this author on: GSW Google Scholar K. Moran; K. Moran Author Search for other works by this author on: GSW Google Scholar Y. Ogawa; Y. Ogawa Author Search for other works by this author on: GSW Google Scholar T. Sakai; T. Sakai Author Search for other works by this author on: GSW Google Scholar J. Schoonmaker; J. Schoonmaker Author Search for other works by this author on: GSW Google Scholar Peter Vrolijk; Peter Vrolijk Author Search for other works by this author on: GSW Google Scholar R. Wilkens; R. Wilkens Author Search for other works by this author on: GSW Google Scholar C. Williams C. Williams Author Search for other works by this author on: GSW Google Scholar Author and Article Information C. Beck Author Univ. Lille I, Lab. Dynam. Sediment. Struct., Villeneuve d'Ascq 59655, France G. Blanc Author A. Mascle Author J. C. Moore Author E. Taylor Author F. Alvarez Author Patrick Andreieff Author R. Barnes Author J. Behrmann Author K. Brown Author M. Clark Author J. Dolan Author A. T. Fisher Author J. Gieskes Author M. Hounslow Author P. McLellan Author K. Moran Author Y. Ogawa Author T. Sakai Author J. Schoonmaker Author Peter Vrolijk Author R. Wilkens Author C. Williams Author Publisher: Société Géologique de France First Online: 03 Mar 2017 Online Issn: 1777-5817 Print Issn: 0037-9409 GeoRef, Copyright 2012, American Geosciences Institute. Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique, Vandoeuvre-les-Nancy, France Bulletin de la Société Géologique de France (1988) IV (1): 129–140. https://doi.org/10.2113/gssgfbull.IV.1.129 Article history First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation C. Beck, G. Blanc, A. Mascle, J. C. Moore, E. Taylor, F. Alvarez, Patrick Andreieff, R. Barnes, J. Behrmann, K. Brown, M. Clark, J. Dolan, A. T. Fisher, J. Gieskes, M. Hounslow, P. McLellan, K. Moran, Y. Ogawa, T. Sakai, J. Schoonmaker, Peter Vrolijk, R. Wilkens, C. Williams; Anatomie et physiologie d'un prisme d'accretion; premiers resultats des forages du complexe de la ride de la Barbade, Leg ODP 110. Bulletin de la Société Géologique de France 1988;; IV (1): 129–140. doi: https://doi.org/10.2113/gssgfbull.IV.1.129 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin de la Société Géologique de France Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Other| May 01, 1988 Advection de fluides interstitiels dans les series sedimentaires du complexe d'accretion de la Barbade (Leg 110 ODP) G. Blanc; G. Blanc Author Univ. Pierre et Marie Curie, Lab. Geochim. Metallogenie, Paris 75252, France Search for other works by this author on: GSW Google Scholar J. M. Gieskes; J. M. Gieskes Author Search for other works by this author on: GSW Google Scholar P. J. Vrolijk; P. J. Vrolijk Author Search for other works by this author on: GSW Google Scholar A. Mascle; A. Mascle Author Search for other works by this author on: GSW Google Scholar C. J. Moore; C. J. Moore Author Search for other works by this author on: GSW Google Scholar E. Taylor; E. Taylor Author Search for other works by this author on: GSW Google Scholar F. Alvarez; F. Alvarez Author Search for other works by this author on: GSW Google Scholar P. Andreieff; P. Andreieff Author Search for other works by this author on: GSW Google Scholar R. Barnes; R. Barnes Author Search for other works by this author on: GSW Google Scholar C. Beck; C. Beck Author Search for other works by this author on: GSW Google Scholar J. Behrmann; J. Behrmann Author Search for other works by this author on: GSW Google Scholar K. Brown; K. Brown Author Search for other works by this author on: GSW Google Scholar M. Clark; M. Clark Author Search for other works by this author on: GSW Google Scholar J. Dolan; J. Dolan Author Search for other works by this author on: GSW Google Scholar A. Fisher; A. Fisher Author Search for other works by this author on: GSW Google Scholar M. Hounslow; M. Hounslow Author Search for other works by this author on: GSW Google Scholar P. McClellan; P. McClellan Author Search for other works by this author on: GSW Google Scholar K. Moran; K. Moran Author Search for other works by this author on: GSW Google Scholar Y. Ogawa; Y. Ogawa Author Search for other works by this author on: GSW Google Scholar T. Sakai T. Sakai Author Search for other works by this author on: GSW Google Scholar Author and Article Information G. Blanc Author Univ. Pierre et Marie Curie, Lab. Geochim. Metallogenie, Paris 75252, France J. M. Gieskes Author P. J. Vrolijk Author A. Mascle Author C. J. Moore Author E. Taylor Author F. Alvarez Author P. Andreieff Author R. Barnes Author C. Beck Author J. Behrmann Author K. Brown Author M. Clark Author J. Dolan Author A. Fisher Author M. Hounslow Author P. McClellan Author K. Moran Author Y. Ogawa Author T. Sakai Author Publisher: Société Géologique de France First Online: 03 Mar 2017 Online Issn: 1777-5817 Print Issn: 0037-9409 GeoRef, Copyright 2012, American Geosciences Institute. Reference includes data from PASCAL, Institute de l'Information Scientifique et Technique, Vandoeuvre-les-Nancy, France Bulletin de la Société Géologique de France (1988) IV (3): 453–460. https://doi.org/10.2113/gssgfbull.IV.3.453 Article history First Online: 03 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation G. Blanc, J. M. Gieskes, P. J. Vrolijk, A. Mascle, C. J. Moore, E. Taylor, F. Alvarez, P. Andreieff, R. Barnes, C. Beck, J. Behrmann, K. Brown, M. Clark, J. Dolan, A. Fisher, M. Hounslow, P. McClellan, K. Moran, Y. Ogawa, T. Sakai; Advection de fluides interstitiels dans les series sedimentaires du complexe d'accretion de la Barbade (Leg 110 ODP). Bulletin de la Société Géologique de France 1988;; IV (3): 453–460. doi: https://doi.org/10.2113/gssgfbull.IV.3.453 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyBulletin de la Société Géologique de France Search Advanced Search This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

Drilling near the deformation front of the northern Barbados Ridge cored an accretionary prism consisting of imbricately thrusted Neogene hemipelagic sediments detached from little-deformed Oligocene to Campanian underthrust deposits by a decollement zone composed of lower Miocene to upper Oligocene, scaly radiolarian claystone. Biostrati-graphically defined age inversions define thrust faults in the accretionary prism that correlate between sites and are apparent on the seismic reflection sections. Two sites located 12 and 17 km west of the deformation front document continuing deformation of the accreted sediments during their uplift. Deformational features include both large- and small-scale folding and continued thrust faulting with the development of stratal disruption, cataclastic shear zones, and the proliferation of scaly fabrics. These features, resembling structures of accretionary complexes exposed on land, have developed in sediments never buried more than 400 m and retaining 40% to 50% porosity. A single oceanic reference site, located 6 km east of the deformation front, shows incipient deformation at the stratigraphic level of the decollement and pore-water chemistry anomalies both at the decollement level and in a subjacent permeable sand interval. Pore-water chemistry data from all sites define two fluid realms: one characterized by methane and chloride anomalies and located within and below the decollement zone and a second marked solely by chloride anomalies and occurring within the accretionary prism. The thermogenic methane in the decollement zone requires fluid transport many tens of kilometers arcward of the deformation front along the shallowly inclined decollement surface, with minimal leakage into the overlying accretionary prism. Chloride anomalies along faults and a permeable sand layer in the underthrust sequence may be caused by membrane filtration or smectite dewatering at depth. Low matrix permeability requires that fluid flow along faults occurs through fracture permeability. Temperature and geochemical data suggest that episodic fluid flow occurs along faults, probably as a result of deformational pumping.

Detailed analysis of ODP Leg 110 cores provides evidence for a complex structural evolution of the frontal thrust system in the northern Barbados Accretionary Prism. Initial east-directed in-sequence thrusts are biostratigraphically documented, and are overprinted towards the west by out-of-sequence overthrusts, largescale folds and penetrative deformation of the accreted rocks. This structural progression is interpreted to reflect the need for secondary shape adjustments of the accretionary prism in order to maintain a critical taper. At present the basal décollement is located within Lower Miocene strata. Accreted Eocene sediments suggest either fossil frontal off-scraping at a lower stratigraphic level or duplex formation and underplating.