Subduction of the Caribbean Plate and basement uplifts in the overriding South American Plate (original) (raw)
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Tectonics, 1985
Since we wrote our paper [Kellogg and Bonini, 1982], a great deal of new information has been published about the complex Caribbean-South American plate boundary. We were pleased that recent multichannel seismic profiles of the South Caribbean deformed belt [Lehner et al., 1983; Lu and McMillen, 1983; Ladd et al., 1984] support our interpretation that Caribbean oceanic crust is actively underthrusting the deformed belt north of Colombia (Figure 1). We also learned that recent drilling by Intercor [International Colombia Resources Corporation] for the Cerrej6n Coal Project northwest of the Sierra de Perij• [Reyes and Luna, 1983] confirmed the existence of the buried thrust faults that we predicted (Figure 2). Schubert [this issue] comments on a brief part of our paper concerning the tectonics of the Venezuelan [M•rida] Andes [Figure 2]. We presented a regional tectonic interpretation of the Caribbean-South American boundary and did not intend to give a detailed review of the late Tertiary geology of the M•rida Andes. We would like to respond to two of Schubert's comments, however, that have broader tectonic implications. The first concerns Copyright 1985 by the American Geophysical Union. Paper number 5T0538. 0278-7407/85/005T-0538502.00 our overthrust model for the M6rida Andes based on the observed gravity field, which Schubert fails to explain. The second comment concerned displacement on the Ke 1 logg and Bonini: Comment ary
Subduction of the Eastern Panama Basin and seismotectonics of northwestern South America
Journal of Geophysical Research, 1981
Spreading along the Cocos-Nazca plate boundary since the breakup of the Farallon plate in the Miocene has resulted in the formation of the Panama basin and a complex interaction of plates in and near northwestern South America. Current plate boundaries have been defined, and segments of subducted lithosphere identified through selection of hypocentral locations of earthquakes, considering only welllocated events, and through focal mechanism determinations. The existence of relict plate boundaries, bathymetric features, and the Panamanian isthmus has affected the subduction process of the Nazca plate beneath Sou_th America and determined the present-day configuration of the subducting lithospheric plate. There is no single triple junction separating the Caribbean, South American, and Nazca plates. Instead, the Panamanian isthmus and surrounding areas are accommodating east-west compression (and a lesser degree of north-south compression) along a series of thrust faults striking NW to NE, and the Andean ranges of Ecuador, Colombia, and Venezeula are moving as a block NNE relative to the rest of the South American plates, along a system of faults following the front of the Eastern Cordillera. The subducted portions of the Panama basin and old Farallon plate have become segmented into three pieces recognized in this study. From north to south, they are (1)a 'Bucaramanga' segment continuous with the Caribbean seafloor northwest of Colombia, (2) a 'Cauca' segment continuous with oceanic crust (Nazca plate) currently being subducted beneath South America at the Colombia-Ecuador trench, and (3) an 'Ecuador' segment at the northern end of the subducted lithospheric plate which is dipping at a small angle to the east beneath northern Peru. The segmentation of the subducted plate can be explained by the buoyancy of bathymetric features which have been partially subducted. _ INTRODUCTION The Andean margin of South America and the circum-Caribbean region have long been areas of special interest to geologists and geophysicists. Since the later 1960's, studies both on land and at sea have focused on determining the structure and history of the area within the framework of plate tectonics. These have been especially successful along the Andean margin south of the equator [Barazangi and Isacks, 1976], along schumacher, 1976], now represented by a scarp along the southern limit of the 'Galapagos gore' (Figure 1). The Galapagos gore represents the limits of crust created by spreading on the Cocos-Nazca plate boundary [Holden and Dietz, 1972]. The configuration of the spreading center-transform fault system within the Panama basin has been determined by bathymetric and marine magnetic studies reported by van Andel et al. [1971], Hey et al. [1972, 1977], Handschumacher [1976], and Lonsdale and Klitgord [1978]; the active and relict plate • Now at Department of Geological Sciences, University of Texas at Austin, Austin, Texas 78712. the Middle American trench [Molnar and Sykes, 1969; Dean boundaries as determined by those studies are shown 'm Figand Drake, 1978], and near the Galapagos triple junction [Hey ure 2. et al., 1972, 1977].
Geophysical Journal International, 2018
We examine the hypocentral distribution of seismicity and a series of geodetic velocity vectors obtained from Global Positioning System observations between 1994 and 2015 both offshore and mainland northwestern South America (66 • W-77 • W; 8 • N-14 • N). Our analysis, that includes a kinematic block modelling, shows that east of the Caribbean-South American-North Andes plates triple junction at ∼68 • W; 10.7 • N, right-lateral easterly oriented shear motion (∼19.6 ± 2.0 mm yr −1) between the Caribbean and South America plates is split along two easterly striking, right-lateral strike-slip subparallel fault zones: the San Sebastián fault that runs offshore the Venezuelan coast and slips about 17.0 ± 0.5 mm yr −1 and the La Victoria fault, located onshore to the south, which is accumulating strain equivalent to 2.6 ± 0.4 mm yr −1. West of the triple junction, relative right-lateral motion between the Caribbean and South American plates is mostly divided between the Morrocoy and Boconó fault systems that strike northwest and southwest from the triple junction, respectively, and bound the intervening North Andes plate that shows an easterly oriented geodetic slip of 15.0 ± 1.0 mm yr −1 relative to the South American plate. Slip on the Morrocoy fault is right-lateral and transtensional. Motion across the Boconó fault is also right-lateral but instead transpressional, divided between ∼9 and 11 mm yr −1 of right-slip on the Boconó fault and 2-5 mm yr −1 of convergence across adjacent and subparallel thrust faults. Farther west of the triple junction, ∼800 km away in northern Colombia, the Caribbean plate subducts to the southeast beneath the North Andes plate at a geodetically estimated rate of ∼5-7 mm yr −1 .
Tectonics, 1992
Recent marine and onland geophysical and geological investigations along the northern Caribbean plate boundary call for a review of its tectonic interpretation, in the light of a new compilation of the seismological data avalaible from Cuba to Puerto Rico. We show that the shallow seismicity in the northeastern Caribbean is concentrated along an east-west trending lineament corresponding to the trace of the major strike-slip fault system. The most intense seismicity is located around restraining bends such as southern Cuba and northern Hispaniola. The stress and strain distribution deduced from focal mechanisms and microtectonic analysis lead us to infer a small N-S convergence component associated with the major eastward strike-slip motion of the Caribbean plate versus North America. Earthquake distribution and focal mechanisms suggest the existence of a lithospheric slab inherited from the frontal subduction under the Lesser Antilles diping down under Puerto Rico and eastern Hispaniola. We propose a model in which this slab is disconnected from the Atlantic oceanic lithosphere by transcurrent faulting along the plate boundary. INTRODUCTION As evidenced by Molnar and Sykes [1969], the Caribbean domain and Central America form a small lithospheric plate inserted between North and South America that is moving eastward relative to North America (Figure 1). Its northern boundary is a left-lateral transcurrent fault system connected around its eastern end to the subduction of the Atlantic oceanic lithosphere under the Lesser Antilles. Recent geophysical and geological investigations have been conducted along the northern Caribbean plate boundary, both at sea [Scanlon et al.,
Record and Constraints of the Eastward Advance of the Caribbean Plate in Northern South America
Memoir 108: Petroleum Geology and Potential of the Colombian Caribbean Margin
A great variety of complex structures found in northern Colombia, northern Venezuela, the Lesser Antilles, Barbados, and Trinidad and Tobago record the eastward movement of the Caribbean plate relative to the South American plate through time. The development of these structures includes transtensional and foredeep basins as well as fold-and-thrust belts that become younger eastward since the Cretaceous. In northern Colombia, terrane accretion began in the Triassic and ended in the late Cretaceous, along the Gulf of Uraba, and the Sinu-San Jacinto Belt. Further east, the structure offshore Guajira, east from the Bucaramanga fault, is characterized by accretion involving the South American metamorphic basement. Well and seismic data in the Maracaibo Basin record the Paleogene flexure related to terrane collision and accretion. In the Gulf of Venezuela, offshore eastern Falcon, and La Vela, transtensional basins record the eastward movement of the Caribbean plate. Onshore northern Venezuela, the Villa de Cura subduction mélange in the Cordillera de la Costa nappes represents the accretionary wedges involving ophiolites of Eocene age. The Guarico flysch records the flexure of the accretionary wedge during Oligocene time and fills the foredeep of the same age. The Cariaco, Carupano, and La Blanquilla are pull-apart basins related to a younger Oligocene-Miocene-stage strike-slip as the Caribbean plate advances toward the east. Ophiolitic obduction of the Caribbean oceanic domain onto the accreted terranes is represented by the thrusted ophiolites of Isla Margarita. The Monagas area or Serrania del Interior folded belt is a characterized Oligocene to Miocene thinskinned thrusting involving the passive margin units of the South American plate and is overlain by the Carapita accretionary wedge. The Maturin Basin is the flexural basin associated with the loading of the Serrania del Interior thrust stack and extends to the east toward the Delta Centro and Punta Pescador areas, in the Orinoco delta and south of Trinidad. The Gulf of Paria pull-apart basin in eastern Venezuela and Trinidad developed since the late Miocene and is the easternmost strike-slip basin related to the eastward advance of the Caribbean plate, and terminates against the frontal accretionary wedge of the Caribbean plate of Barbados and Trinidad that is a Miocene to present-day shale-dominated accretionary wedge.
The Triple Junction of the North America, Cocos, and Caribbean Plates: Seismicity and tectonics
Tectonics, 1989
Different kinematic models have been proposed for the triple junction between the North American, Cocos and Caribbean plates. The two most commonly accepted hypotheses on its driving mechanism are (a) the north American drag of the forearc and (b) the cocos Ridge subduction push. We present an updated GPS velocity field which is analyzed together with earthquake focal mechanisms and regional relief. The two hypotheses have been used to make kinematic predictions that are tested against the available data. An obliquity analysis is also presented to discuss the potential role of slip partitioning as driving mechanism. The North American drag model presents a better fit to the observations, although the cocos Ridge push model explains the data in costa Rica and Southern nicaragua. Both mechanisms must be active, being the driving of the Central American forearc towards the NW analogous to a pushpull train. The forearc sliver moves towards the west-northwest at a rate of 12-14 mm/yr, being pinned to the North American plate in Chiapas and western Guatemala, where the strike-slip motion on the volcanic arc must be very small. After the establishment of plate tectonics as a paradigm of geology throughout the 1960s, in the 1970s numerous works attempted to explain tectonics in this new theoretical framework. Different kinematic models were proposed to explain the motion of the forearc sliver along the Cocos-Caribbean subduction, in the framework of the triple junction between the North American, Cocos and Caribbean plates, and particularly for the north of Central America. In one of the first proposals it is suggested that the relative drift of the Caribbean plate to the east gave rise to the formation of N-S grabens in Honduras while southern Guatemala and western Honduras remained pinned to North America 1. This basic model, which did not consider the existence of a forearc sliver yet, was refined, suggesting the existence of a weakness zone along the Volcanic Arc that facilitates the displacement of a forearc sliver dragged laterally, or pulled, by the North American plate motion towards the Northwest 2,3. These works define the basis of the dragging hypothesis (DH) and the deformation in the trailing edge of the Caribbean plate 4,5. The higher South America-North America convergence towards the west has been also proposed as mechanism for the Caribbean-North America pinning on its western edge and the relative extrusion of the Caribbean Plate towards the east 6,7. As an alternative model to explain the north-westward drift of the forearc sliver the slip partitioning in the subduction was proposed 8. This model of slip partitioning has been refuted as the subduction interface is not coupled enough to transmit the necessary forces to drive the upper plate forearc 4,9-12. In addition, it has an insufficient obliquity angle to generate the partition 13 , although it will be discussed below. Towards the southeast of the forearc, in southern Nicaragua and Costa Rica, the GPS vectors show a centrifugal arrangement in front of the
28 The inversion of Mesozoic extensional structures in the northern Andes 29 controlled the location of syn-orogenic successions and dispersal of detritus 30 since latest Maastrichtian time. Our results are supported by detailed 31 geological mapping, integrated provenance (petrography, heavy minerals, 32 geochronology) analysis and chronostratigraphic correlation (palynological 33 and geochronology data) of 13 areas with Palaeogene strata across the 34 central segment of Eastern Cordillera. Thickness trends, spatial and temporal 35 variations of sedimentation rates and provenance signatures indicate that 36 mechanisms driving location of uplifts and tectonic subsidence vary among 37 syn-orogenic depocenters. In the late Maastrichtian-mid Palaeocene time, 38 crustal tilting of the Central Cordillera favored reverse reactivation of the 39 western border of the former extensional Cretaceous basin; block-tilting of the 40 hanging-wall separated two depocenters: a western depocenter (in the 41 Magdalena Valley) and an eastern depocenter (presently along the axial zone 42 of the Eastern Cordillera, Llanos foothills and Llanos basin) of the reactivated 43 fault. In Late Palaeocene to Early Eocene time, as eastern subduction of the 44 Caribbean plate and intraplate magmatic advanced eastward, reactivation of 45 older structures migrated eastward up to the Llanos basin and disrupted the 46 eastern depocenter. These three depocenters were separated by two low-47