Crustal structure of the southwestern colombian caribbean margin: Geological interpretation of geophysical data

The active Colombian Caribbean margin has evolved since the late Cretaceous time, resulting in a complex deformation history involving oblique subduction, accretion, extension and tectonic inversion during the Cenozoic period. The combined interpretation of 2D seismic reflection, gravity and magnetic data provides new insights into the margin configuration (Morrosquillo Gulf area) and the architecture and types of crust present. The margin displays the morphological and tectonic characteristics of a typical accretion-dominated subduction complex. The 3D gravity modelling suggests that the Caribbean Plate is subducting beneath NW Colombia at a low angle of about 5° in an E to SE direction. The major tectonic domains forming the margin include, from west to east: trench, active accretionary prism, outer high and forearc basins. The trench axis coincides with the toe of the active accretionary prism. The active prism corresponds to the deformation front of the Sinú-Colombia Accretionary Wedge. The outer high domain includes the major structural complex formed by the easternmost part of the Sinú-Colombia Accretionary Wedge and the San Jacinto Fold Belt. It represents the fossil part of the accretionary prism which today acts as a dynamic backstop to the active accretionary prism

Arguments for and against the Pacific origin of the Caribbean Plate: discussion, finding for an inter-American origin

Arguments in support of the Pacific origin for the Caribbean Plate are discussed along with others that point to an inter-American origin. Entry of a Pacific-derived plate would have involved unlikely, geometrically complex and highly diachronous events. They would have included changes in direction of subduction, changes in direction of plate migration, major (1000s of km) plate migration, major rotation of large parts of a volcanic arc, major rotations of the Maya and Chortis blocks and diachronous development of flysch/wildflysch deposits as the entering plate interacted with neighbouring elements. The internal structural conformity of the Caribbean Plate and of the Maya and Chortis blocks with regional geology of Middle America shows that no major migrations or rotations have occurred. Coeval, regional deposits of Albian shallow water limestones, Paleocene– Middle Eocene flysch/wildflysch deposits, Middle Eocene limestones, and a regional Late Eocene hiatus show an inter-American location, not a changing Pacific-Caribbean location. Neogene displacement of the Caribbean relative to North and South America amounts to no more than 300 km

Tectonostratigraphic evolution of the Gulf of Venezuela.

Master's thesis in Petroleum Geosciences EngineeringThe Gulf of Venezuela is located at the boundary between the Cretaceous-Cenozoic deformation zone of the South American and Caribbean plates. It is an underexplored area lying between the hydrocarbon-rich Maracaibo Basin and the emergent plays such as the Perla field (Late Oligocene to Early Miocene carbonates) located on the allochthonous terrane. Gravity data, stratigraphy, structural styles, and subsidence plots reveal three main basement provinces in the Gulf of Venezuela: (1) A western Paleozoic basement (Maracaibo province) with continental-affinity similar to those in the Guajira Peninsula and the Maracaibo Basin; (2) a central province covering the area of the Urumaco trough offshore with Meso-Neoproterozoic rocks (Urumaco province); and (3) an easternmost province, with Cretaceous Caribbean arc rocks, related to the Leeward Antilles island arc system (Caribbean province). Two major interpreted strike-slip faults define the boundary between the main provinces. The Cuiza-Río Seco fault is the western flank of the Urumaco trough offshore and represents a structural and stratigraphic abrupt change that is proposed as the boundary between the Maracaibo autochthonous province and the allochthonous provinces. The Pueblo Nuevo fault is proposed to be the continuation onland of a major interpreted strike-slip fault, defining the boundary between the central and easternmost province. In addition, the Cuiza-Río Seco and Pueblo Nuevo faults accommodate strain partitioning as well as the Oca- Ancón fault but at different timing, due to oblique compression of the Caribbean plate against the South American plate. Furthermore, a pop-up structure associated with the Sierra de Perijá is recognized in the southernmost Maracaibo province, allowing to define about ̴ 70-80 km of right-lateral strike-slip displacement along the Oca fault. This fault has a relevant role to the present-day basement configuration, since it has displaced eastwards and segmented the northern part of the basement provinces, resulting in a more complex distribution that needs to be considered to reconstruct the geologic history. Considering the continuation of the Maracaibo block northwards, this region might hold promising opportunities for hydrocarbons exploration, where the Maracaibo Basin petroleum system might extends offshore into the Gulf of Venezuela.The Conjugate Basins, Tectonics and Hydrocarbons Project (CBTH)submittedVersio

Caribbean paleogeography

95 p. : ill., maps (some col.) ; 26 cm.Includes bibliographical references (p. 59-72)."This paper presents a series of detailed paleogeographical analyses of the Caribbean region, beginning with the opening of the Caribbean basin in the Middle Jurassic and running to the end of the Middle Miocene. Three intervals within the Cenozoic are given special treatment: Eocene-Oligocene transition (35-33 Ma), Late Oligocene (27-25 Ma), and early Middle Miocene (16-14 Ma). While land mammals and other terrestrial vertebrates may have occupied landmasses in the Caribbean basin at any time, according to the interpretation presented here the existing Greater Antillean islands, as islands, are no older than Middle Eocene. Earlier islands must have existed, but it is not likely that they remained as such (i.e., as subaerial entities) due to repeated transgressions, subsidence, and (not incidentally) the K/T bolide impact and associated mega-tsunamis. Accordingly, we infer that the on-island lineages forming the existing (i.e., Quaternary) Antillean fauna must all be younger than Middle Eocene. The fossil record, although still very poor, is consistent with the observation that most land mammals lineages entered the Greater Antilles around the Eocene-Oligocene transition. Western Laurasia (North America) and western Gondwana (South America) were physically connected as continental areas until the mid-Jurassic, ca. 170 Ma. Terrestrial connections between these continental areas since then can only have occurred via landbridges. In the Cretaceous, three major uplift events, recorded as regional unconformities, may have produced intercontinental landbridges involving the Cretaceous Antillean island arc. The Late Campanian/Early Maastrichtian uplift event is the one most likely to have resulted in a landbridge, as it would have been coeval with uplift of the dying Cretaceous arc. However, evidence is too limited for any certainty on this point. The existing landbridge (Panamanian Isthmus) was completed in the Pliocene; evidence for a precursor bridge late in the Middle Miocene is ambiguous. We marshal extensive geological evidence to show that, during the Eocene-Oligocene transition, the developing northern Greater Antilles and northwestern South America were briefly connected by a "landspan" (i.e., a subaerial connection between a continent and one or more offshelf islands) centered on the emergent Aves Ridge. This structure (Greater Antilles + Aves Ridge) is dubbed GAARlandia. The massive uplift event that apparently permitted these connections was spent by 32 Ma; a general subsidence followed, ending the GAARlandia landspan phase. Thereafter, Caribbean neotectonism resulted in the subdivision of existing land areas. The GAARlandia hypothesis has great significance for understanding the history of the Antillean biota. Typically, the historical biogeography of the Greater Antilles is discussed in terms of whether the fauna was largely shaped by strict dispersal or strict continent-island vicariance. The GAARlandia hypothesis involves elements of both. Continent-island vicariance sensu Rosen appears to be excludable for any time period since the mid-Jurassic. Even if vicariance occurred at that time, its relevance for understanding the origin of the modern Antillean biota is minimal. Hedges and co-workers have strongly espoused over-water dispersal as the major and perhaps only method of vertebrate faunal formation in the Caribbean region. However, surface-current dispersal of propagules is inadequate as an explanation of observed distribution patterns of terrestrial faunas in the Greater Antilles. Even though there is a general tendency for Caribbean surface currents to flow northward with respect to the South American coastline, experimental evidence indicates that the final depositional sites of passively floating objects is highly unpredictable. Crucially, prior to the Pliocene, regional paleoceanography was such that current-flow patterns from major rivers would have delivered South American waifs to the Central American coast, not to the Greater or Lesser Antilles. Since at least three (capromyid rodents, pitheciine primates, and megalonychid sloths) and possibly four (nesophontid insectivores) lineages of Antillean mammals were already on one or more of the Greater Antilles by the Early Miocene, Hedges' inference as to the primacy of over-water dispersal appears to be at odds with the facts. By contrast, the landspan model is consistent with most aspects of Antillean land-mammal biogeography as currently known; whether it is consistent with the biogeography of other groups remains to be seen"--P. 3

Plate-tectonic evolution of the Gulf of Mexico and Caribbean region

A geologic- kinematic model for the evolution of the Gulf of Mexico and Caribbean region is built within a framework provided by a detailed Late Paleozoic (Alleghenian) plate reconstruction and a revised North American (NOAM) and South American (SOAM) relative motion history. From the Middle Jurassic to the Campanian, SOAM migrated east-southeast from NOAM. From the Carapanian to the Eocene. Little or no NOAM-SOAM relative motion occurred, although minor sinistral transpression is suggested. Since the Eocene, minor west-northwest convergence between NOAM and SOAM has occurred along pre-existing fracture zones. Three stages of evolution are recognized which correlate with these phases of relative motion. Stage 1: mainly carbonate shelves fringed the Gulf of Mexico and "Proto-Caribbean" passive rifted margins, during plate separation. Stage 2: the Caribbean Plate (CARIB) progressively entered the NOAM-SOAM gap from the Pacific by subduction of Proto-Caribbean crust beneath the Greater Antilles, Stage 3: CARIB migrated east by 1200 km, subducting Proto-Caribbean crust and forming the Lesser Antilles Arc, Transform faults have dissected the original Greater Antilles Arc, and nappes in the Venezuelan Andes have been emplaced southeastwards onto the northern SOAM margin, diachronously from west to east. Field work done in Dominican Republic, both near Puerto Plata and in the southwest sector, indicates that 1) Cuba and northern and central Hispaniola are parts of one original Greater Antilles arc, 2) this arc collided with the Bahamas in the Late Paleocene=Mid Eocene, and 3) Hispaniola has been assembled by strike-slip juxtaposition of terranes from the west

Basin evolution and shale tectonics on an obliquely convergent margin: the Bahia Basin, offshore Colombian Caribbean

Oblique convergent margins accumulate strike‐slip deformation that controls basin formation and evolution. The Bahia Basin is located offshore, proximal to major strike‐slip fault systems that affect northern Colombia. It lies behind the toe of the modern accretionary prism, where the Caribbean Plate is being subducted obliquely beneath South America. This is the first attempt using 3D seismic reflection data to interpret a complex strike‐slip basin at the western end of the southern margin of the Caribbean Plate. Detailed 2D and 3D seismic mapping of regional unconformities and faults is used to describe the structural geometry, timing and evolution of extensional and strike‐slip faults which controlled the formation of the basin. Analysis of the fault zones is coupled with a description of the seismic‐stratigraphic units observed within the Bahia Basin to reconstruct the spatial and temporal evolution of deformation, and to evaluate the influence of the pervasive shale tectonics observed in the area. The results, presented as a series of structural‐paleogeographic maps, illustrate an initial stage of transtension that controlled the formation of shale‐withdrawal minibasins from late Oligocene to late Miocene times. The continuous deformation and northward expulsion of the Santa Marta Massif resulted in transpression during Pliocene times, leading to basin inversion and ultimate closure of the basin. Basin evolution along the southern Caribbean oblique, convergent margin, shows the occurrence of a complex interaction between subduction and major‐onshore strike‐slip fault systems, and illustrates how strain‐partitioning led to the break‐up and lateral displacement of early accretionary prisms formed along the margin

Reconciling the Cretaceous breakup and demise of the Phoenix Plate with East Gondwana orogenesis in New Zealand

Following hundreds of millions of years of subduction in all circum-Pacific margins, the Pacific Plate started to share a mid-ocean ridge connection with continental Antarctica during a Late Cretaceous south Pacific plate reorganization. This reorganization was associated with the cessation of subduction of the remnants of the Phoenix Plate along the Zealandia margin of East Gondwana, but estimates for the age of this cessation from global plate reconstructions (∼86 Ma) are significantly younger than those based on overriding plate geological records (105–100 Ma). To find where this discrepancy comes from, we first evaluate whether incorporating the latest available marine magnetic anomaly interpretations change the plate kinematic estimate for the end of convergence. We then identify ways to reconcile the outcome of the reconstruction with geological records of subduction along the Gondwana margin of New Zealand and New Caledonia. We focus on the plate kinematic evolution of the Phoenix Plate from 150 Ma onward, from its original spreading relative to the Pacific Plate, through its break-up during emplacement of the Ontong Java Nui Large Igneous Province into four plates (Manihiki, Hikurangi, Chasca, and Aluk), through to the end of their subduction below East Gondwana, to today. Our updated reconstruction is in line with previous compilations in demonstrating that as much as 800–1100 km of convergence occurred between the Pacific Plate and Zealandia after 100 Ma, which was accommodated until 90–85 Ma. Even more convergence occurred at the New Zealand sector owing to spreading of the Hikurangi Plate relative to the Pacific Plate at the Osbourn Trough, with the most recent age constraints suggesting that spreading may have continued until 79 Ma. The end of subduction below most of East Gondwana coincides with a change in relative plate motion between the Pacific Plate and East Gondwana from westerly to northerly, of which the cause remains unknown. In addition, the arrival of the Hikurangi Plateau in the subduction zone occurred independent from, and did not likely cause, the change in Pacific Plate motion. Finally, our plate reconstruction suggests that the previously identified geochemical change in the New Zealand arc around 105–100 Ma that was considered evidence of subduction cessation, may have been caused by Aluk-Hikurangi ridge subduction instead. The final stages of convergence before subduction cessation must have been accommodated by subduction without or with less accretion. This is common in oceanic subduction zones but makes dating the cessation of subduction from geological records alone challenging

The evolution of the intra-Carpathian basins and their relationship to the Carpathian mountain system

Thesis (Ph.D.)--Massachusetts Institute of Technology, Dept. of Earth and Planetary Sciences, 1982.Microfiche copy available in Archives and ScienceVita.Includes bibliographies.by Leigh Handy Royden.Ph.D

Foreland basins: lithospheric flexure, plate strength and regional stratigraphy

Foreland basin subsidence through time is reproduced in this study, as the flexure of an elastic beam in an inviscid fluid under the vertical stress, caused by discrete-distributed loads. Thus, seismostratigraphic data from the Timor Sea peripheral foreland basin, in northwestern Australia, and the Putumayo retroarc foreland basin in the Colombian Andes, are forward modeled, at chronostratigraphic intervals, to assess the evolving geodynamic conditions of the basins. Results show that the accommodation in foreland basins varies as the depositional basement is vertically adjusted according to the regionally isostatic compensation of the lithosphere. Distributed tectonic (thrust belts) and sedimentary loads that act independently but consecutively during tectono-stratigraphic events, throughout the evolution of foreland basins, control the deflection of the plate that forms the foredeep of these depocenters. Accordingly, the loads limit the amount and distribution of available space for sedimentation. Results also reduce the role of eustasy to only 2 to 6% of the total accommodation, even in marine foreland depocenters. The strength of the plate remains invariable during the evolution of the basin at time scales of 106 to 107 m.y. Asymmetrical flexure, produced by oblique plate convergence, induces diachronuous and local marine cycles at basin scale (100’s of km). Stratigraphic development of non-marine foreland basins is more likely to respond to the evolution of the equilibrium-profile during basin history

Orogenic architecture of the Mediterranean region and kinematic reconstruction of its tectonic evolution since the Triassic

The basins and orogens of the Mediterranean region ultimately result from the opening of oceans during the early break-up of Pangea since the Triassic, and their subsequent destruction by subduction accommodating convergence between the African and Eurasian Plates since the Jurassic. The region has been the cradle for the development of geodynamic concepts that link crustal evolution to continental break-up, oceanic and continental subduction, and mantle dynamics in general. The development of such concepts requires a first-order understanding of the kinematic evolution of the region for which a multitude of reconstructions have previously been proposed. In this paper, we use advances made in kinematic restoration software in the last decade with a systematic reconstruction protocol for developing a more quantitative restoration of the Mediterranean region for the last 240 million years. This restoration is constructed for the first time with the GPlates plate reconstruction software and uses a systematic reconstruction protocol that limits input data to marine magnetic anomaly reconstructions of ocean basins, structural geological constraints quantifying timing, direction, and magnitude of tectonic motion, and tests and iterations against paleomagnetic data. This approach leads to a reconstruction that is reproducible, and updatable with future constraints. We first review constraints on the opening history of the Atlantic (and Red Sea) oceans and the Bay of Biscay. We then provide a comprehensive overview of the architecture of the Mediterranean orogens, from the Pyrenees and Betic-Rif orogen in the west to the Caucasus in the east and identify structural geological constraints on tectonic motions. We subsequently analyze a newly constructed database of some 2300 published paleomagnetic sites from the Mediterranean region and test the reconstruction against these constraints. We provide the reconstruction in the form of 12 maps being snapshots from 240 to 0 Ma, outline the main features in each time-slice, and identify differences from previous reconstructions, which are discussed in the final section