Cayman Trough Research Articles

Low marine terraces of Grand Cayman Island

Twenty levelling profiles across the shore zone of Grand Cayman Island reveal the presence of six low marine terraces above present sea level. The lowest and youngest one at about 2 m elevation is the most widespread and probably represents Sangamon interglacial high sea level. Higher terraces are much eroded and probably much older, but none provides evidence of post-terrace warping. Similarities in age and elevation of the 2 m terrace on this island to those in north-western Yucatan, northern Jamaica, the Bahamas and Florida suggest that vertical movements at Grand Cayman Island have been minor during at least the past 125 000 years, even with its nearness to the tectonically active Cayman Trough.

Shallow-Water Limestones from Slope off Grand Cayman Island

Limestones of Oligocene age obtained from a submersible at two sites about 3,000 m deep on the Oriente Slope and from two shallow drill holes on nearby Grand Cayman Island were deposited in shallow marine waters. All samples contain calcareous algae and shallow-water foraminifera, but no deep-water remains were found. The limestone on the slope was lithified in fresh water, according to its petrography and stable isotopes. A third dive encountered massive beds presumed to be outcrops of limestone that dip southward down the slope. We conclude that the region began to subside along a hinge line parallel to the Oriente Slope during Oligocene time and soon became too deep to generate a shallow-water carbonate deposit. This subsidence was associated with plate movements along the Cayman Trough.

Geological and Geophysical Investigation of the Mid-Cayman Rise Spreading Center: Geochemical Variation and Petrogenesis of Basalt Glasses

Basalt glasses erupted from the transverse spreading center within the Cayman Trough have higher contents of , Zr, Y, Sr, and Ba than typical mid-ocean ridge basalts (MORB). These compositional features are unique and the glasses appear to be transitional between fractionated MORB and incompatible-element enriched basalts from certain oceanic regions such as the mid-Atlantic Ridge near 43°N, the triple junction near Bouvet, and Fracture Zone B at the FAMOUS (MAR 37°N) spreading center. The major element compositional variation defines an apparent cotectic, in the normative plagioclase-pyroxene-olivine triangle, which is systematically offset into the plagioclase field compared to most other MORB trends. Model fits based on the assumption of simple, single-stage fractional crystallization are very good for both major and trace elements, with no apparent "decoupling" of the incompatible elements as observed in the FAMOUS (37°N) spreading center. These calculations indicate that, like typical MORB, three-phase crystallization is required to explain the major and trace element variations, although only plagioclase and olivine are observed as liquidus (phenocryst) phases. High-pressure crystallization of clinopyroxene is suggested by mineral assemblages in Cayman Trough gabbros and by analogy with experimental data, and may be favored by the special tectonic setting of the Cayman Trough. Other geochemical peculiarities of the glasses may be related in part to local characteristics of the mantle source beneath the equatorial Atlantic and/or Caribbean plate.

The Galapagos Rift at 86° W: 3. Sheet flows, collapse pits, and lava lakes of the Rift Valley

It has long been known that pillow basalts are a dominant feature of oceanic volcanism on midocean ridges. Recent studies in the Cayman Trough, East Pacific Rise, and Galapagos Rift valley have shown that sheet flows are also an important component, especially on ridges with intermediate and fast opening rates. This paper describes the surface forms of such sheet flows observed in the Galapagos Rift valley. The principal types are lobate, smooth, rippled, and wrinkled, as well as hackly and jumbled forms. Collapse pits of a wide range of sizes are common; they appear to result from subsidence of the lava as a consequence of distal spreading of the flow and/or headward drainback into the subsurface plumbing system. Lava pillars are numerous around collapse pits, and current evidence suggests that they most likely are spiracles produced by water trapped below an advancing flow and rising through it to the surface. From Hawaiian analogs we conclude that sheet flows can be considered a submarine equivalent of surface‐fed pahoehoe, while the pillow basalts are analogous to subaerial tube‐fed pahoehoe. We view the difference between sheet flows and pillow basalts to be the result of different degrees of channelization and rates of delivery of lava to flow fronts, associated with differences in duration and rate of eruption. In this model the sheet flows and pillowed ridges of the Galapagos Rift are the analogs of the early and the late products of an Hawaiian eruptive event, respectively. The sheet flows represent early, brief but voluminous eruptions. These are followed by more sustained, slower but steadier eruptive phases that produce pillow basalts after an internal plumbing system has been well established. Thus pillowed volcanics should normally overlie sheet flow complexes of only slightly greater age, and stratigraphie sections accumulated over long intervals should consist of alternating sequences of sheet and pillow flows. This model leads to several different ways of explaining the distinction between the apparent dominance of pillows on slow spreading ridges and the sheet flow and pillow complexes on faster spreading ridges.

The tectonic significance of basalts and dacites in the Wagwater Belt, Jamaica

SummaryThe Wagwater Belt is a fault-bounded structural unit in which more than 3000 m of early Tertiary sedimentary and volcanic rocks are exposed. Geochemical analyses of the volcanic rocks show that they comprise a bimodal suite of plateau-type tholeiitic basalts and calcalkaline dacites. The extrusion of these volcanics is associated with the development of an interarc basin, the Wagwater Basin, at the beginning of the Cenozoic Era. The Wagwater Basin formed as a result of the splitting of a mature late Cretaceous volcanic arc into a frontal and third arc represented by the Blue Mountain Massif and the Clarendon Block respectively. This model for Jamaica can be correlated with tectonic events occurring in the NW Caribbean during the early Tertiary. The creation of the Wagwater Basin and the eruption of the basalts is related to the initial opening of the Cayman Trough. The cessation of dacite volcanic activity in Jamaica signified the separation of the Caribbean Plate from the East Pacific Farallon Plate.

Quaternary faulting along the Caribbean-North American plate boundary in Central America

Recent detailed mapping along the Motagua fault zone and reconnaissance along the Chixoy—Polochic and Jocotán—Chamelecón fault zones provide new information regarding the nature of Quaternary deformation along the Caribbean—North American plate boundary in Central America. The southern boundary of the Motagua fault zone is defined by a major active left-slip fault that ruptured during the February 4, 1976 Guatemala earthquake. The recurrent nature of slip along the fault is dramatically demonstrated where stream terraces of the Río El Tambor show progressive left-slip and vertical (up-to-the-north) slip. Left-slip increases from 23.7 m (youngest mappable terrace) to 58.3 m (oldest mappable terrace) and vertical slip increases from 0.6 m to 2.5 m. The oldest mappable terrace crossed by the fault appears to be younger than 40,000 years and older than 10,000 years. Reconnaissance along the Chixoy—Polochic fault zone between Chiantla and Lago de Izabal has located the traces of a previously unmapped major active left-slip fault. Geomorphic features along this fault are similar to those observed along the active trace of the Motagua fault zone. Consistent and significant features suggestive of left-slip have so far not been observed along the Guatemala section of the Jocotán—Chamelecón fault zone. In Central America, the active Caribbean—North American plate boundary is comprised of the Motagua, Chixoy—Polochic, and probably the Jocotán—Chamelecón fault zones, with each accommodating part of the slip produced at the mid-Cayman spreading center. Similarities in geomorphic expression, apparent amount of left-slip, and frequency and magnitude of historical and instrumentally recorded earthquakes between the active traces of the Motagua and Chixoy—Polochic fault zones suggest a comparable degree of activity during Quaternary time; the sense and amount of Quaternary slip on the Jocotán—Chamelecón fault zone remain uncertain, although it appears to be an active earthquake source. Uplift of major mountain ranges on the north side of each fault zone reflects the small but consistent up-to-the-north vertical component (up to 5% of the lateral component) of slip along the plate boundary. Preliminary findings, based on offset stream terraces, indicate a late Quaternary slip rate along the Caribbean—North American plate boundary of between 0.45 and 1.8 cm/yr. Age dating of offset Quaternary terraces in Guatemala will allow refinement of this rate.

Rock and paleomagnetic evidence for the existence and nature of a Cayman Trough spreading center

Rock and paleomagnetic measurements have been made on a set of 54 basalts dredged from 17 stations located within the central valley of the Cayman Trough. Seventeen of the samples could be oriented with respect to the in situ vertical by the use of lava cooling ledges and stalactites.Peak remanent intensities in the Cayman Trough are lower than peak Mid-Atlantic Ridge values by a factor of 2 or 3 even after allowance is made for the latitudinal variation in geomagnetic field intensity. This difference is likely to be the result of the combined effects of relatively low saturation magnetization and more advanced low temperature oxidation of titanomagnetite in the Cayman Trough basalts.Five young, reversely magnetized basalts, similar to those found on the Mid-Atlantic Ridge, occur in the Cayman Trough sample set.Plots of the magnetic parameters of the pillow basalts with distance from the axis of the trough show broad highs or lows associated with the axis. Our interpretation is that crustal formation in the central valley has occurred recently, but it has either been rather diffuse or is now much disturbed tectonically on a small scale in comparison with the Mid-Atlantic Ridge. Analysis of the distribution of Curie temperatures suggests that crustal accretion has been slow (0.1–0.4 cm year−1 half-rate) and may have ceased in the area studied at about 0.6 Ma BP.

Inversion of magnetic anomalies and sea-floor spreading in the Cayman Trough

For some time, sea-floor spreading has been hypothesized for the Mid-Cayman Rise based on inferences from seismicity, heat flow, topography and plate geometry. Here we present magnetic anomaly inversions from which a reasonable record of sea-floor spreading emerges. We obtain total opening rates of 20 ± 2 mm/yr for 0–2.4 m.y. B.P. and 40 ± 2 mm/yr for 2.4–6.0 m.y. B.P. Data on the west flank extend the half-opening rate of 20 mm/yr back to 8.3 m.y. B.P. Spreading has been very nearly symmetric. These new observations place important constraints on plate tectonic reconstructions by defining the relative motion between the North American and Caribbean plates. They also shed some light on sea-floor spreading processes in which the spreading center is a secondary feature in the sense that it is over an order of magnitude shorter than the adjoining transform faults.

The geology and evolution of the Cayman Trench

The geology and stratigraphic relationships of the Cayman Ridge, Nicaraguan Plateau, and mid-Cayman spreading center, which have been determined from the succession of rocks recovered at 80 dredge stations in the Cayman Trench, are consistent with the inferred crustal structure of the region deduced from published geophysical data. The Cayman Ridge and Nicaraguan Plateau are composed of metamorphic, plutonic, volcanic, sedimentary, and carbonate rock units that typically crop out along continental margins and in island arcs. In contrast, the trench floor is composed of mafic and ultramafic rocks identical to those recovered from the major ocean basins. Our petrographic, radiometric, and paleontologic data are correlated with the regional geology of Central America and the Greater Antilles and suggest that the Cayman Ridge and Nicaraguan Plateau developed as a single, broad island arc during the Laramide Orogeny. By late Eocene time, volcanism had greatly diminished, uplift and erosion had exposed the underlying igneous rock, thick clastic sequences had been deposited in newly formed grabens, and a zone of east-west axial accretion had been created between the rifted ridge and plateau. An average spreading rate of .4 cm/yr across the mid-Cayman spreading center since the Eocene accounts for approximately 200 km of left-lateral displacement between the Cayman Ridge and Nicaraguan Plateau. The geologic histories of the ridge and plateau differ slightly after the Eocene, but general subsidence, at an average rate of 6 cm/1,000 yr, caused progressive restriction of carbonate banks and reefs to a few isolated islands and algal pinnacles. The pre-Cretaceous history of the Cayman Trench has been extrapolated from the Paleozoic-Mesozoic geology and structure of Central America and Cuba, while the Cretaceous to Holocene evolution of the trench has been related to the relative motions between the North American, South American, and Caribbean plates. Plate convergence during the Cretaceous caused southerly subduction of oceanic lithosphere beneath the ancestral Cayman Ridge–Nicaraguan Plateau, which subsequently led to the formation of a chain of volcanic islands to the south, along the North American–Caribbean plate boundary. Numerous ophiolite-like outcrops that fringe the north Caribbean margin are believed to reflect a Late Cretaceous closure of this subduction zone. Early Tertiary left-lateral shear and tensional stresses along this plate boundary split the Cayman Ridge from the Nicaraguan Plateau, and a small spreading center was created in the rift. Declining isotherms beneath the ridge and plateau caused general subsidence and local tectonic re-equilibration in late Tertiary time.

Petrology and geochemistry of mafic rocks from the Cayman Trench: Evidence for spreading

Research Article| February 01, 1977 Petrology and geochemistry of mafic rocks from the Cayman Trench: Evidence for spreading Michael R. Perfit Michael R. Perfit 1Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 Search for other works by this author on: GSW Google Scholar Author and Article Information Michael R. Perfit 1Lamont-Doherty Geological Observatory of Columbia University, Palisades, New York 10964 Publisher: Geological Society of America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 Geological Society of America Geology (1977) 5 (2): 105–110. https://doi.org/10.1130/0091-7613(1977)5<105:PAGOMR>2.0.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 Michael R. Perfit; Petrology and geochemistry of mafic rocks from the Cayman Trench: Evidence for spreading. Geology 1977;; 5 (2): 105–110. doi: https://doi.org/10.1130/0091-7613(1977)5<105:PAGOMR>2.0.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 Rocks dredged from 16 localities withing the Cayman Trench suggest a crustal sequence identical to that reported from the mid-oceanic ridge. Serpentinites, serpentinized peridotites, cumulate mafic rocks, and gabbros crop out deep along the precipitous north-trending ridges. Numerous basalts and dolerites crop out somewhat higher, along with minor amounts of limestone and sediment. Major-element variations and trace-element abundances substantiate the abyssal tholeiitic nature of the basalts and indicate possible shallow fractionation from a primary melt in the upper mantle. A combination of dynamic, hydrothermal, and contact metamorphism near the axial valley is proposed to explain the observed metamorphic features. The geochemical data, along with pubulished geophysical evidence, support the hypothesis of a mid-Cayman spreading center in this tectonically complex region. 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.

Morphology off northern Honduras, northwestern Carribean Sea

Over 5500 km of sounding lines were used to construct a detailed bathymetric chart of the sea floor between Honduras and the southern Cayman Trough. The submarine morphology is related clearly to the tectonic setting. Complex transform faulting has ruptured the crust seaward of the Honduras continental margin into a series of deep grabens separated by irregular submarine ridges. Because of the proximity of the Cayman Trough, the western continental margin is a faulted platform characterized by an irregular shelf as narrow as 10 km and a steeply dipping slope; both shelf and slope have been modified substantially by the growth of thick reef masses. Further east, tectonism is reduced as a result of the divergent trends of the Cayman Trough and the Honduras continental margin. Consequently, the eastern margin sector is a depositional platform consisting mostly of a broad, smooth shelf and gentle slopes. Submarine erosion and local slumping have steepened the slope throughout the area.

Return to the Deep: The Cayman Trough

Return to the Deep: The Cayman Trough

Structural Evolution of the Honduras Continental Margin and the Sea Floor South of the Western Cayman Trough

The interpretation of 2,500 km of seismic-reflection profiles and its synthesis with the results of previous work reveal a four-stage development for the Honduras continental margin since late Mesozoic time. Late Cretaceous–early Eocene orogenesis deformed basement rocks and pre-orogenic units offshore Honduras. Following subsidence during middle Tertiary time, postorogenic units I and II blanketed the eroded preorogenic rocks, creating a distinct angular unconformity. The widespread distribution and uniform thickness of the postorogenic sediments suggest deposition during a tectonically quiescent period. Pliocene time marked the onset of block-faulting activity which fragmented the crust into irregular ridges and basins in northern Central America and along the Honduras continental margin and the western Cayman Trough. The continental shelf and slope of Honduras have been prograding since the Miocene Epoch; turbidites are now filling the proximal fault basins offshore Honduras. Assuming that regional tectonism and continental margin development are relatable to lithospheric plate interactions, the deformed preorogenic units are interpreted as having been buckled by convergent plate motions during Late Cretaceous–early Eocene time. Plate slippage may have lapsed during middle Tertiary time, as inferred from the nature of the postorogenic units. This phase of plate passivism was terminated during Pliocene time by block-faulting activity, which presumably represents the resumption of plate motions along the Cayman Trough that have persisted to the present in the northwestern Caribbean.

The deposition of reef-derived sediment upon a bathyal slope: The deep off-reef environment, north of Discovery Bay, Jamaica

The steep submarine slope north of Jamaica was formed as a normal fault scarp during the early rifting of the Cayman Trough. It is overgrown at the top by flourishing reefs, and below these a series of irregular valleys have been cut into the rocks of the slope and run downslope to at least 2,500 m. Cores from these valleys contain thin layers of reef-derived sands interbedded with pelagic muds of Quaternary age. Cores from topographically high areas recovered only pelagic muds. It is shown that bottom currents and turbidity currents are both unlikely to have been the agencies responsible for the deposition of the reef-derived sands, but that they were probably emplaced by either free avalanching or by sand flow.

Evidence for sea-floor spreading in the Cayman Trough

New seismic reflection and bathymetric data reveal that the rough topography in the central quarter of the Cayman Trough consists predominantly of north-south oriented ridges and valleys. Ridges with a relief of 200–2,000 m lie on either side of a north-south trending V-shaped valley which extends from the north to the south wall of the trough. We suggest that this valley and the flanking ridges represent an axis of sea-floor spreading for which we propose the name Mid-Cayman Rise. Although overall depths are greater for the Mid-Cayman Rise (rift valley, 5,500–6,000 m; flanking ridges, 3,500–4,000 m) than are typical of the mid-oceanic rise, striking similarities in morphology and sediments are noted. Both rises exhibit an axial rift valley, rough sediment-free basement near the axis, increasing depth and increasing burial by sediments with distance from the axial rift, and symmetry in basement morphology about the rift. Earthquake epicenters are clustered near the ends of the rift, where it intersects linear deeps along the north and south walls of the trough. The rift in the Cayman Trough is approximately equidistant from the two ends of the trough, suggesting that the Mid-Cayman Rise may have been spreading symmetrically for a long time, in response to relative motion between the Americas and Caribbean plates. Our interpretations impose important constraints on tectonic models for the Cenozoic history of plate motions in the Caribbean region.

Diapirlike Features Offshore Honduras: Implications Regarding Tectonic Evolution of Cayman Trough and Central America: Reply

A seismic-reflection survey along the continental margin of Honduras has uncovered an assemblage of diapirlike bodies. Features such as disrupted and upturned flank reflectors as well as a domed and faulted overburden suggest that the bodies are truly piercement structures. Although unequivocal evidence is lacking, the diapirs are probably salt. The bodies are shallow and corroboration could be obtained by drilling (Fig. 1). The Cayman Trough is a locus of intense tectonism along which the Caribbean plate is considered to be decoupled from the North America plate. Salt offshore Honduras (Caribbean plate) may have been displaced eastward by about 1,000 km relative to presumably equivalent salt deposits in Guatemala (North America plate). Hence, slip rates for the lithospheric plates in the northwestern Caribbean can be estimated to lie between 1 and 2 cm/yr, depending on whether the transcurrent motions were initiated in the mid-Mesozoic or the mid-Cenozoic. The bulk of the data available from this and other studies convinces one that the Cayman Trough is a strike-slip feature. Consequently, a sphenochasm model for the structural evolution of the Gulf of Honduras that delegates strike-slip faulting to a subordinate role is improbable. A model involving the relative clockwise rotation of Honduras from Yucatan in the mid-Mesozoic followed in the mid-Tertiary by roughly 300 km of sinistral, strike-slip displacement localized along the Cayman Trough is conceivable but unlikely. Additional magnetic surveying will probably be needed to test this model.

Ultrabasic Rocks from the Cayman Trough, Caribbean Sea

Ultrabasic rocks have been dredged from the center of the Cayman Trough, a postulated boundary between the North American and Caribbean plates, 160 km southwest of Grand Cayman Island. Serpentinite, which may be altered spinel Iherzolite, dominates the collection and is believed to be bedrock in the station area. Two samples of a clinopyroxene-plagioclase-ilmenite crystal cumulate were found.

Eastern Yucatan Continental Margin and Western Caribbean Tectonics

The eastern Yucatan continental margin and the rest of the Western Caribbean are characterized by linear fault ridges that merge southwestward. This tectonic fabric is believed to be the result of the rotation of the Yucatan peninsula away from Guatemala-Honduras. Initial rotation formed the Yucatan basin and fragmented the Greater Antillean geosyncline in Late Jurassic-mid-Cretaceous time. Late Cenozoic rotation produced the Cayman Ridge-Cayman Trough-Nicaraguan Rise complex, and the late Cenozoic orogenic activity in eastern Cuba, Hispaniola, and Jamaica. Left-lateral motion along the Cayman Trough since the Eocene is believed to be several tens of kilometers, not 180-200 km as previously suggested by others.

Circum-Caribbean Tectonic and Igneous Activity and the Evolution of the Caribbean Plate: Reply

Convergence of the North and South American blocks and northeastward movement of the East Pacific-Caribbean plate during the Late Cretaceous and early Tertiary led to the Laramide tectonic and igneous activity that has been recorded in the geology of the circum-Caribbean region. Volcanism in Central America and the initiation of major transcurrent faulting along northern South America during the late Eocene suggest that the Caribbean decoupled from the East Pacific plate near the end of the Laramide Orogeny. Lack of post-Eocene structural activity in the Greater Antilles is consistent with the initiation of eastward movement of the Caribbean plate during the Eocene. The evolution of the Cayman Trough and the history of orogenic activity in Cuba can be explained by assuming that Caribbean lithosphere was transferred to the Americas plate as the trough developed from west to east. As each new section was added to the eastward-growing trough, a new transform fault formed in the Caribbean lithosphere to connect the eastern end of the trough with the Cuban Trench. This west to east stepping of the plate boundary transferred “Caribbean” lithosphere to the Americas plate and allowed underthrusting and related tectonic activity to continue longer in eastern than in western Cuba. The presence of intermediate depth earthquakes and high seismicity along the Puerto Rico Trench suggest that the Atlantic lithosphere which underthrust Puerto Rico prior to the Oligocene is beginning to break away from the Americas plate. Fault displacements inferred along the Caribbean-Americas boundary in the Greater Antilles are equivalent to a constant post-Eocene eastward movement of 0.5 cm/yr for the Caribbean plate.

Middle Cretaceous Nappe Structures in Puerto Rican Ophiolites and Their Relation to the Tectonic History of the Greater Antilles: Reply

Radiolarian chert, serpentinized peridotite, pillow lava, and metamorphosed tholeiitic rocks form an ophiolite association in southwestern Puerto Rico. These are the oldest rocks in Puerto Rico and apparently represent exposed oceanic crust. Relations between the lithologies are complex; there is an older complex of serpentinized peridotite and metatholeiite 110 m.y. old or older, an intermediate pillow lava and felsite association, and a younger radiolarian chert formation of middle Cretaceous (Albian) or older age. A gravitational nappe structure, showing northward movement probably of Albian or earlier age, is composed of a disharmonically deformed sheet of radiolarian chert. Serpentinite occurs in small lenses along the sole of the nappe and probably served as a lubricant for movement of the nappe. A second nappe is suggested, on less extensive data, to have moved Campanian-Maestrichtian pelagic limestones northward over the older chert nappe. This movement occurred in Maestrichtian or later time and is perhaps synchronous with smaller northward slides of the same formation during the Maestrichtian about 20 km to the north. Other northward slides occurred in early Tertiary time in several places in southern Puerto Rico. Northward gravity transport of the nappes and other slides is opposite to the sense of tectonic transport indicated by northward-dipping axial planes in the volcanic and volcano-sedimentary rocks in central Puerto Rico. Similar relations exist in Cuba where thrust and gravity slides show northward motion toward and into the volcanic pile. Gravity transport may have been from an oceanic ridge northward toward a trench, with volcanism developing between the two structures. Early buckling of lithosphere plates into an oceanic ridge and complementary trench, before rupture and subduction, may provide the necessary relief for gravitational trench-ward slides. A speculative geologic history of the Greater Antilles contains three stages: (1) pre-Albian buckling of the lithosphere into ridge and trench, with gravitational sliding of crustal rocks toward the trench; (2) rupture of the lithosphere and Albian-Campanian (or Maestrichtian) subduction, forming volcanism between ridge and trench; (3) choking of the Benioff zone by continental lithosphere of the northern plate, and further Maestrichtian to Eocene movement resolved along lateral faults with fault-controlled volcanism along an ancestral Cayman trough–Puerto Rico trench trend.