Newly available seismic reflection data are applied to an interpretation of the Cibao basin of Hispaniola. The data include multichannel seismic reflection profiles from Samana Bay and the central part of the Cibao Valley, and single-channel seismic profiles from the western offshore extension of the Cibao Valley and the Windward Passage. A single track of GLORIA imagery through the Windward Passage is also used. The data in Samana Bay reveal a major, active, easterly oriented normal fault (transcurrent?) and a significant increase in sedimentation from the north, which probably began during Miocene to Pliocene time. A seismic reflection line in the central part of Cibao Valley demonstrates that the sedimentary material in the valley is at least 5 km thick, with the thickest section in the north adjacent to the Septentrional fault. The southern margin of the Cibao Valley appears to be the locus of a hingeline, although minor faults may be present. The oldest sedimentary basin fill overlying Cretaceous basement is probably of middle Miocene age based on outcrops of rock. At the western end of the Cibao Valley, the Septentrional fault curves northwesterly before going offshore. In addition, the Tortue fault, which extends offshore along the north coast of Haiti, is an extension of either the Guayubin-Hispaniola fault zones or is a southwestern branch of the Septentrional fault. It can be identified on the sidescan sonar images in Windward Passage.

ABSTRACT The Greater Tortue/Ahmeyim gas field discovered by Kosmos Energy in 2015 in the deep-water Mauritania–Senegal Basin opened a new giant gas province in Northwest Africa. The discovery well, Tortue-1, was drilled in Mauritania by Kosmos and the Mauritania National Oil Company (SMHPM) and discovered dry gas in Cenomanian reservoirs within a stratigraphic–structural trap of approximately 90 km 2 (34.7 miles 2 ). Two additional wells, Guembeul-1A in Senegal (drilled by Kosmos and PETROSEN) and Ahmeyim-2 in Mauritania (drilled by Kosmos and SMHPM), support a field resource estimate of approximately 25 tcf (0.71 tcm) GIIP. Additional drilling outside the Ahmeyim Field proves this gas province extends from northern Senegal to central Mauritania and may contain up to 50–100 tcf (1.42–2.84 tcm) GIIP. The Mauritania–Senegal Basin saw several exploration campaigns throughout approximately 60 years. However, the deep-water petroleum system had not been recognized as it was assumed; (1) the Cenomanian-Turonian (C-T) mudstones were the only viable source rocks, and these would be immature in the deep water; (2) the basin outside of the salt province was undeformed—thus lacking trapping geometries; and (3) a sufficient volume of high-quality reservoir was not likely to be found in the lower slope. The Greater Tortue/Ahmeyim Field discovery dispelled these paradigms while giving new insights into deep-water exploration. The African margin has been described as a passive margin; however, a clear deformation event occurred in the Late Cretaceous to Early Tertiary on faults linked to hyperextended crust. This deformation event likely coincides with the heat event, which is evidenced today by elevated heat flow across the outer basin. This heat event matured an Early Cretaceous source or sources producing high-maturity dry gas. The lower slope to basin floor depositional systems contain very thick, stacked packages of sand, which have high-quality reservoir properties because of rework by multiple current processes. The Greater Tortue/Ahmeyim Field reached final investment decision (FID) in December 2018 with partners BP Exploration and national oil companies SMHPM (Société Mauritanienne des Hydrocarbures et de Patrimoine minier) and PETROSEN (Senegal). The field will be developed with a floating liquefied natural gas (FLNG) design.

ABSTRACT There have been 248 giant fields (>500 MMBOE) found since 2000. Information gleaned from studying these giant fields’ data has shown that the industry has undergone at least five major paradigm shifts in the past 20 years. First, unconventional and tight gas exploration has transformed the industry. It is expanding to South America, Oman, Bahrain, China, and other countries. Second, creaming curves show step changes in success in finding giant combination and stratigraphic traps. These traps now comprise 60% of the volumes, up from 10% to 15% historically, and attributed to improved seismic imaging. The most important trends are salt-sealed carbonate reef complexes in the Caspian Basin, Egypt, Brazil, and Turkmenistan. Of equal importance are passive margin turbidites, commonly de-risked with amplitude vs. offset (AVO) and 3-D seismic reservoir imaging. Third, ultra-deep drilling to 5–9 km below mudline is finding oil, rich liquids, and porosity. Some of this can be explained by lowered geothermal gradients beneath thick salt, but other oils occur at temperatures of 160°C–180°C with very high pressures. We discuss new concepts to explain these deep liquids from the standpoint of pressure, volume, temperature (PVT) data and fractionization during migration. Fourth, giant fields have been found overlying oceanic crust, breaking a long-held paradigm that these kinds of plays do not work. Last, deep, overpressured upward hydrodynamic flow and tilted hydrocarbon contacts have been documented in many basins. This may ultimately turn out to be more of a “norm” than an exception.

Abstract The Permo-Triassic succession in Spain records the change from a Pangaea configuration and compressive tectonic regime inherited from the Variscan orogeny, to an exten-sional tectonic setting accompanied by continental break-up and westward expansion of the Neotethyan ocean (Fig. 10.1 ). During latest Carboniferous–Early Permian times, latest Variscan orogenic extension associated with andesitic volcan-ism produced small continental basins in the Pyrenees, the east and central Iberian Ranges, and along the southern margin of the Iberian Massif. Extension continued into and during Late Permian times, creating half-graben and graben continental sedimentary basins bounded by Palaeozoic highs. Subsequent westward expansion of Neotethys led to successive marine transgression–regression cycles along the eastern and southern margins of the Iberian plate, which drowned the Palaeozoic highs during Middle Triassic (Ladinian) times. Although the Atlantic Ocean did not open during Triassic times, slow subsidence allowed the Neotethys to prograde westwards around the Iberian Massif, so that the Pyrenean-Cantabrian, Betic and Lusitanian basins became interconnected and extended towards the Grand Banks area (Fig. 10.1 ; Jansa et al . 1980 ). Permo-Triassic southward propagation of pre-existing Norwegian-Greenland sea rift systems and westward propagation of the Tethys rift system represented the initial phase of post-Variscan plate reorganization, spanning some 90 Ma (Fig. 10.1a ). The development of different rift systems during this initial break-up of Pangaea was related to a series of strike-slip faults that dissected the Variscan foldbelt and its associated foreland areas. The development of the different rift systems of central and western Europe

Abstract The Yaou deposit, located in French Guiana within the Guiana Shield, is one of the most promising gold deposits of the regional Paleoproterozoic greenstone belt. It displays numerous quartz monzodiorite bodies aligned along a sinistral shear zone where a five-deformation phases model is established at the camp scale. The ductile D 1/2YA phase is responsible for the main penetrative foliation while the D 3YA phase is related to shearing. An intrusive event is identified as being pre to syn-D 3YA . The following phase D 4YA represents a brittle quartz-carbonate veining set hosted preferentially within intrusive bodies and along the shear zone. A local D 5YA brecciation event crosscuts the D 4YA veins. Among this deformation history, two auriferous events (D 3YA and D 4YA ) control the overall grade of the Yaou gold deposit. More specifically, most of the Au grade is associated with the main economic D 4YA veining event, where the gold is visible and linked to Py 4 within an ankerite/hematite rich alteration halo. At the microscopic scale, results of in situ analyses using LA-ICP-MS on pyrite show that metasediment-hosted Py 0 is a primary source of submicroscopic gold having a low contribution to the total endowment. Py 3 shows some gold content due to possible remobilization of Au D0YA . Gold in Py 4 is found as submicroscopic gold, as micro-inclusions and as infilling fractures in association with elements such as Te, Ag and Bi. Most contribution to the Au grade is from micro-inclusions and, to a lesser extent, from free and submicroscopic gold. The ore shoot locations are lithologically controlled for Au D0YA (metasedimentary unit-hosted), structurally controlled (shear zone-hosted) for Au D3YA and rheologically controlled for the Au D4YA (intrusion-hosted). The deposit is clearly polyphase both at the macroscopic and the microscopic scales, invisible gold is associated with As whereas visible gold is observed as inclusions in pyrite with high contents of Ag, Te and Bi. We define an early low-grade enrichment of Au D0YA to Au D3YA followed by a later high-grade event, Au D4YA supporting polyphase mineralization processes. This study confirms that orogenic gold deposits can be formed by remobilization and/or new gold inputs during multiple deformation, veining and hydrothermal events.