The American margins of the Caribbean comprise basins and accreted terranes recording a polyphase tectonic history. Plate kinematic models and reconstructions back to the Jurassic show that Mesozoic separation of the Americas produced passive margins that were overridden diachronously from west to east by allochthonous Caribbean plate-related arc and oceanic complexes. P-T-t and structural data, sedimentary provenance, and basin-subsidence studies constrain this history. Caribbean lithosphere is Pacifi c-derived and was engulfed between the Americas during their westward drift as the Atlantic Ocean opened. This began ca. 120 Ma with development of a west-dipping Benioff zone between Central America and the northern Andes, now marked by the Guatemalan and Cuban sutures in North America and by the northern Colombian and Venezuelan "sutures" of South America, persisting today as the Lesser Antilles subduction zone. Most Caribbean high-pressure metamorphic complexes originated at this subduction zone, which probably formed by arc-polarity reversal at an earlier west-facing Inter-American Arc and was probably caused by westward acceleration of the Americas. The mainly 90 Ma Caribbean basalts were extruded onto preexisting Caribbean crust ~30 m.y. later and are not causally linked to the reversal. The Great Caribbean Arc originated at this trench and evolved up to the present, acquiring the shape of the preexisting ProtoCaribbean Seaway. The uplift and cooling history of arc and forearc terranes, and history of basin opening and subsidence, can be tied to stages of Caribbean plate motion in a coherent, internally consistent regional model that provides the basis for further studies.

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The 1300‐m‐thick turbiditic Bude Formation was deposited in a lake, Lake Bude, but disagreement persists over whether the environment was a deltaic or deep‐water fan. The tectonic setting of the lake was the northern flank of a northerly advancing Variscan foreland basin, close to the Westphalian palaeo‐equator. Palaeocurrents indicate sediment sourcing from all quadrants except the south. There is a dm‐m scale cyclicity, whereby sandstone bodies comprising amalgamated event beds alternate with mudstone intervals containing non‐amalgamated event beds. The ‘ideal’ cycle is a symmetrical coarsening‐up/fining‐up cycle, consisting of three facies (1, 2 and 3) arranged in 12321 order. Facies 3, in the middle of the cycle, is an amalgamated sandstone body up to 10 m thick which interfingers laterally with thin (cm) mudstone layers. The sandstone body comprises amalgamated beds of very fine sandstone which are largely massive and up to 0.4 m thick. Channels are absent except for scours up to 0.2 m deep which truncate the interfingering mudstone layers. Sandstone bodies are inferred to be tongue‐shaped in three dimensions. Facies 1 and 2, completing the 12321 cycle, are respectively dark‐grey fine and light‐grey coarse, varved(?) mudstone containing thin (< 0.4 m) sandstone event beds. Fossils and burrows indicate that facies 1 and 2 were deposited, respectively, in brackish (rarely marine) and fresh water. Hence, the ideal cycle (12321) reflects an upward decrease then increase in salinity (brackish‐fresh‐brackish); this is attributed to the lake sill being periodically overtopped by the sea, due to glacio‐eustatic sea‐level oscillations. The resulting oscillations in lake depth produced the coarsening‐up/fining‐up (regressive‐transgressive) cyclicity, the central sandstone body representing the regressive maximum. Event beds are interpreted as river‐fed turbidites deposited during catastrophic storm‐floods. Combined‐flow ripples and other wave‐influenced structures occur in event beds throughout the ideal cycle, suggesting deposition of the entire Bude Formation above storm wave base. The proposed environment is a shelf, of continental‐shelf dimensions, but lacustrine instead of marine. Sandstone bodies are interpreted to be river‐connected tongues or lobes. The absence of cycles containing nearshore or emergent facies is attributed to: (i) the lake sill preventing the water level from falling below sill level, thereby insulating the lake floor from eustatically forced emergence; and (ii) relatively distal deposition, beyond the reach of shoreline progradations. The lack of palaeoflow from the south is attributed to a (now eroded?) deep‐water trough lying to the south, in front of the northerly advancing orogen. Some facies 2 laminated mudstone beds grade laterally into massive and/or contorted beds, interpreted as in‐situ seismites (Facies 4), consistent with an active foreland basin setting. Development of seismites was possibly facilitated by gas bubbles and/or weak cohesion in the (fresh water) bottom mud....

The Ross Formation (Namurian, Ireland) and the near-identical Bude Formation (Westphalian, England), both amply described in the literature, are used by oil companies as deep-sea-fan reservoir analogues. However, the Ross Formation is reinterpreted here, like the Bude Formation in recent publications, to be composed of river-fed turbidites deposited on the wave-influenced northern shelf of a Variscan foreland-basin lake, which also had a southern flysch trough.Key features of these formations are: (i) two classes of thin (<0.4m) sandstone "event bed" in shale comprising (a) structureless turbidite-like beds, and (b) rippled beds with combined-flow ripples and/or hummocky cross-stratification, neither structure having previously been reported from the Ross Formation; (ii) "trademark" tabular packets (1-10m) of amalgamated event beds which interfinger laterally with mudstones; (iii) sharp packet bases and tops; (iv) rare sinuous channel fills; and (v) rare thick (1-10m) shale units, each containing a thin (cm-dm) fossiliferous band.The fossil bands are interpreted here as maximum flooding surfaces, reflecting glacioeustatic marine incursions over the lake spill point (sill), forcing the lake to rise and to turn marine or strongly brackish; these bands define Galloway-type depositional sequences 50-100m thick. During eustatic falls, the lake was forced down to sill level, where it perched and turned fresh (desalination). Intervals containing sandstone packets are attributed to the falling-stage and lowstand systems tracts, each packet representing a higher-order lowstand systems tract. Packets are interpreted as tongue shaped, supplied by river-fed underflows. Packet bases (sharp) represent the storm-wavegraded equilibrium shelf profile, glacioeustatically forced to its lowstand position. On this erosion surface were deposited underflow turbidites produced by floods in the catchment. Occasional catastrophic storms on the lake shaved these turbidites and interfingering fair-weather muds back down to the equilibrium level, leaving behind a subsidence-accommodated increment whose surface was sculpted by storm wind and wave currents, forming hummocks, combined-flow ripples and erosional megaflutes. Whenever a river-fed underflow accompanied one of these storms, the resulting highly erosive combined flow carved a sinuous channel on the wave-sculpted equilibrium surface. Sandstone-shale intervals separating the sandstone packets are interpreted as transgressiveand highstand systems tracts. They contain both turbidites and wave-modified turbidites (rippled beds), deposited on the out-of-equilibrium drowned shelf.A gradual rotation in sole-mark direction with time in both formations is attributed to a reversal of Coriolis deflection as the plate drifted north across the equator, causing underflows (deflected alongshelf geostrophically) to flow first NEwards and then SWwards on an inferred SE-facing shelf.The lack of evidence for emergence in the Ross and Bude Formations, in spite of the great thicknesses (460m and 1,290m, ...

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The Honna Formation, of Coniacian age, consists of several hundred metres of polymictic clast‐supported conglomerate associated with sandstone and mudstone. Five conglomerate facies are recognized: ungraded beds; inverse graded beds; normal graded beds; inverse‐to‐normal graded beds; and parallel‐stratified beds. These facies are interpreted as the deposits of subaqueous cohesionless debris flows and/or high‐density turbidity currents. The depositional environment was a deep‐water, gravelly fan that draped a fault‐controlled, basin‐margin slope. The fan is inferred to have passed upslope directly into an alluvial fan (unpreserved); hence, the name fan delta can be applied to the overall depositional system. This type of fan delta, of which the Brae oilfield in the North Sea is an example, is defined here as a deep‐water fan delta. The lack of a shelf is in marked contrast to other types of fan delta. Three facies associations are recognized in the Honna Formation: subaqueous proximal‐fan conglomerates, distal‐fan turbiditic sandstones, and pro‐fan/interfan mudstones with thin sandy turbidites. The proximal fan is envisaged as an unchannelled gravel belt with a downslope length of at least 20 km; such a long subaqueous gravel belt lacks a known modern analogue. The distal fan was an unchannelled sandy extension of the proximal gravel belt. It is postulated that the Honna Formation accumulated in a foreland basin which migrated westwards from the Coast Mountains where the Wrangellia‐Alexander terrane was colliding with North America. In this model, the Honna fan delta was sourced by a (west‐verging) thrust sheet whose sole‐thrust was the Sandspit Fault immediately to the east. Deep‐water fan deltas appear to develop preferentially when eustatic sea‐level is relatively high, so that the‘feeder’ alluvial fan is small, and gravelly throughout. In petroleum exploration and field development, care should be taken to distinguish deep‐water fan deltas from base‐of‐slope (canyon‐fed) submarine fans, because the two systems differ significantly in terms of coarse‐sediment distribution.

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