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Trinidad geology. Figure 4. Three-dimensional view of the geologic map of the Southern Basin-Range of Trinidad taken from the larger geologic map of Trinidad overlain on topography as shown in Figure 2. All named major faults and folds are identified along with the sites where we collected paleostress information from outcrops of mesocale faults, which showed evidence for north-northwest-south-southeast compression. The large, red arrow shows the direction of displacement that can explain the late Miocene-Pliocene structures (thrusts, folds, and strike-slip faults) and the stress field of Figure 9.
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Kinematic analysis of faults in Trinidad reveal three main stages of the tectonic evolution of the southeastern Caribbean–South American plate boundary.
The polyphase evolution of Trinidad results from the eastward motion of the Caribbean arc and the propagation of the southern Subduction-Transform Edge Propagator (STEP) fault of the Caribbean sub...
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Context 1
... below the unconformity are highly deformed because of intense folding and thrusting. Rocks above the unconformity are locally deformed by strike-slip faults and thrusts, in particular in the Southern Basin and Southern Range (Figure 4). Babb and Mann (1999) recognized a middle Miocene thrusting event that affected the Southern basin and may be related to the late middle Miocene uplift of the Central Range ( Figure 2). ...Context 2
... example, we found this trend of compression at site Mayaro4 where bedding planes dip 40° to the south, and where tilting occurred during faulting and north-vergent thrusting (cf. the pretilt and posttilt striation in the diagram Mayaro4 of Figure 9). Note that, even if the fault slips were measured in a north-vergent fault-bend fold (Figure 4), the fault diagram mainly shows strike-slip faults. Generally, in fault slip studies, shortening is more often represented by strike-slip state of stress rather than a compressional state of stress. ...Context 3
... north-northwest-south-southeast trend of compression is also compatible with rightlateral and left-lateral slips on oblique ramps associated with thrusts in southern Trinidad (Figures 4, 9). For example, at Point Radix, strike-slip faulting of this compressional stage occurred during a 40° southern tilting of the Mayaro Formation, which is of Pliocene age (Figure 10). ...Context 4
... found no evidence for normal faults in this orientation while making observations along the coastline. Our structural and stress field analysis suggest that the mapped onshore north-trending faults could be left-lateral strike-slip faults related to the foldthrust system developed in the Southern Range during south-southeast-trending compression (Figures 4, 9). ...Context 5
... east-northeast-trending synclines of southern Trinidad involve the Pliocene sandstones of the Mayaro and Erin Formations, which confirms the proposed late Miocene-Pliocene age of the south-southeast-trending compression (Figure 4). In the Central Range, we found this trend of compression at sites P. Manza, Mayo1, and Fernando. ...Context 6
... site Mayaro1, the Pliocene Mayaro Formation is cut by reverse and strike-slip faults of the south-southeast-trending compression and strike-slip faults of the east-southeast-trending compression (Figure 7). The second compression reactivates east-west normal fault with a right-lateral sense (Figures 7, 14). As discussed above, normal faulting may have various causes such as foreland flexuring, gravity, sediments compaction, or stress permutation during strike-slip deformation. ...Context 7
... discussed above, normal faulting may have various causes such as foreland flexuring, gravity, sediments compaction, or stress permutation during strike-slip deformation. Site Mayaro1 is located close to the Columbus Basin and is characterized by east-and northwest-trending normal faults (Figure 14). With only three fault measurements, we cannot compute stress axes, but a north-northeast-trending extension as indicated by the white arrow in Figure 12, is possible and would suggest stress permutation of the recent strike-slip regime. ...Citations
... . Román et al., 2021), the northern Lesser Antilles (Philippon et al., 2020), Trinidad and Tobago (Hippolyte & Mann, 2021), and the Venezuelan margin (Beardsley & Avé Lallemant, 2007;. Rosencrantz (1990), Heubeck et al. (1991), Dolan et al. (1991), Escuder-Viruete et al. (2008), Boschmann et al. (2014), Garrocq et al. (2021), and Escalona et al. (2021) have all presented geologic and marine geophysical evidence for a similarly curved, semi-continuous series of back-arc basins adjacent to the plutonic and volcanic complexes of the eastern Caribbean region that may provide important structural and stratigraphic records of the Great Arc during the Late Cretaceous and Paleogene. ...
The 110,000 km² Yucatan Basin in the northern Caribbean Sea is critical for understanding the Late Cretaceous to Recent tectonic evolution of the Caribbean‐North American plate boundary. This study integrates gravity, magnetic, and a 5,500 km grid of 2D seismic data to carry out a tectonostratigraphic analysis of the Yucatan Basin. These data provide the first recognition of 38–102 km‐long spreading ridges that constrain a SW‐NE opening direction in the western Yucatan Basin. The age of this oceanic crust is constrained to be late Paleocene‐middle Eocene (57–42 Ma) based on heat flow measurements, depth‐to‐seafloor, and three sedimentary sequences inferred to be Eocene—Recent in age based on stratigraphic correlations to distant wells. We interpret the Yucatan Basin as a back‐arc basin formed during the northeastward movement of the Caribbean volcanic arc that is now exposed in Cuba, evolved during the early Cretaceous to middle Eocene, and was terminated by collision with the Bahama carbonate platform during the late Paleocene to middle Eocene. We identify regional, left‐lateral strike‐slip faults that extend into the Cuban volcanic arc, as observed in other active back‐arc basins. We propose that the Yucatan back‐arc basin once formed the northwestern extension of age‐equivalent back‐arc basins in Hispaniola, where the basin is inverted, topographically elevated, and strongly shortened, and in the Lesser Antilles where the Paleogene back‐arc basin has remained undeformed and submarine. This once‐continuous back‐arc basin was disrupted and left‐laterally offset by ∼500 km during the Late Eocene‐Recent formation of the Cayman trough strike‐slip system.
