Petroleum in the Zagros BasinA Late Tertiary Foreland Basin Overprinted onto the Outer Edge of a Vast Hydrocarbon-Rich Paleozoic-Mesozoic Passive-Margin Shelf

Author(s):  
Z. R. Beydoun ◽  
M. W. Hughes Clarke ◽  
R. Stoneley

2021 ◽  
pp. M57-2021-29
Author(s):  
A.K. Khudoley ◽  
S.V. Frolov ◽  
G.G. Akhmanov ◽  
E.A. Bakay ◽  
S.S. Drachev ◽  
...  

AbstractAnabar-Lena Composite Tectono-Sedimentary Element (AL CTSE) is located in the northern East Siberia extending for c. 700 km along the Laptev Sea coast between the Khatanga Bay and Lena River delta. AL CTSE consists of rocks from Mesoproterozoic to Late Cretaceous in age with total thickness reaching 14 km. It evolved through the following tectonic settings: (1) Meso-Early Neoproterozoic intracratonic basin, (2) Ediacaran - Early Devonian passive margin, (3) Middle Devonian - Early Carboniferous rift, (4) late Early Carboniferous - latest Jurassic passive margin, (5) Permian foreland basin, (6) Triassic to Jurassic continental platform basin and (7) latest Jurassic - earliest Late Cretaceous foreland basin. Proterozoic and lower-middle Paleozoic successions are composed mainly by carbonate rocks while siliciclastic rocks dominate upper Paleozoic and Mesozoic sections. Several petroleum systems are assumed in the AL CTSE. Permian source rocks and Triassic sandstone reservoirs are the most important play elements. Presence of several mature source rock units and abundant oil- and gas-shows (both in wells and in outcrops), including a giant Olenek Bitumen Field, suggest that further exploration in this area may result in economic discoveries.



1990 ◽  
Vol 127 (4) ◽  
pp. 299-308 ◽  
Author(s):  
Peter D. Clift ◽  
Alastair H. F. Robertson

AbstractThe Argolis Peninsula, southern Greece, is believed to form part of a Pelagonian microcontinent located between two oceanic basins, the Pindos to the west and theVardar to the east, in Triassic to Tertiary time. In eastern Argolis, two important units are exposed: (i) the Ermioni Limestones cropping out in the southwest; (ii) the Poros Formation, observed on an offshore island in the northeast, and on the adjacent mainland. Both these units comprise late Cretaceous (Aptian-Maastrichtian) pelagic limestones, calciturbidites, lenticular matrix- and clast-supported limestone conglomerates and slump sheets. However, the Poros Formation is distinguished from the Ermioni Limestones by the presence of bituminous micritic limestones and an increasing proportion of shale up sequence. These successions are deep-water slope carbonates that once formed the southeast-facing passive margin of the Pelagonian platform (Akros Limestone). Beyond this lay a late Cretaceous ocean basin in the Vardar Zone. This ocean was consumed in an easterly-dipping subduction zone in latest Cretaceous (?) to early Tertiary time, giving rise to an accretionary complex (Ermioni Complex). During early Tertiary (Palaeocene-Eocene) time the passive continental margin (Pelagonian Zone) collided with the trench and accretionary complex to the east. As the suture tightened, former lower-slope carbonates (Ermioni Limestones) were accreted to the base of the over-riding thrust sheets and emplaced onto the platform. Farther west, bituminous upper slope carbonates (Poros Formation) flexurally subsided and passed transitionally upwards into calcareous flysch and olistostromes in a foreland basin. These sediments were then overridden by the emplacing thrust stack and themselves underplated. Late-stage high-angle faulting then disrupted the tectonostratigraphy, in places juxtaposing relatively high and low structural levels of the complex.



2016 ◽  
Vol 4 (3) ◽  
pp. SP21-SP32 ◽  
Author(s):  
Shaoru Yin ◽  
Guangfa Zhong ◽  
Yiqun Guo ◽  
Liaoliang Wang

The Pliocene to recent Taixinan basin is a unique foreland basin built on the northeastern part of the northern passive margin of the South China Sea (SCS). We have used multichannel seismic profiles tied to well controls from ODP Leg 184 to investigate the tectonic and sedimentary characteristics of the foreland basin. We defined three seismic sequences, dated respectively to the Pliocene (5.33–2.5 Ma), early Quaternary (2.5–1.0 Ma), and late Quaternary (1.0 Ma–present). They represent three stages of evolution of the foreland basin. We have recognized seven types of seismic facies, which are parallel-to-subparallel, progradational, fill-type, divergent mounded, wavy, lenticular, and chaotic facies, and are interpreted as hemipelagic deposits, deltas, submarine canyon fills, levees, sediment waves, submarine fans, and mass transport deposits, respectively. Seismic facies analysis indicates that sedimentation within the foreland basin has been dominated by turbidity currents and the other gravity transport processes. Tectonically, the foreland basin consists of three structural zones: an eastern wedge-top, a central foredeep, and a western forebulge zones. Different from a typical foreland basin, however, the basin extends in the northeast–southwest direction, which is oblique to the north–south-striking Taiwan orogenic zone, but parallel to the northern SCS passive margin, where the basin is hosted, suggesting that the foreland basin is significantly influenced by the development of the passive margin. In addition, the basin displays a distinctive inverted-triangle-shaped downstream-converging sediment dispersal system instead of ideal transverse or longitudinal drainage systems common in a typical foreland basin. We have suggested that the Pliocene to recent Taixinan basin is an atypical foreland basin, which was formed as a flexural response of tectonic loading by the Taiwan orogenic wedge, but strongly affected by its passive continental margin background.



2011 ◽  
Vol 182 (6) ◽  
pp. 479-491 ◽  
Author(s):  
Pierre Maurizot

Abstract New Caledonia lies at the northern tip of the Norfolk ridge, a continental fragment separated from the east Gondwana margin during the Late Cretaceous. Stratigraphic data for constraining the convergence that led to ophiolitic nappes being obducted over Grande Terre during the Eocene are both few and inaccurate. To try and fill this gap and determine the onset of the convergence, we investigated the lithology, sedimentology, biostratigraphy and geodynamic context of the Late Cretaceous – Palaeogene sedimentary cover-rock succession of northern New Caledonia. We were able to establish new stratigraphic correlations between the sedimentary units, which display large southwest-verging overfolds detached along a basal argillite series, and reinterpret their interrelationships. The sediments from the Cretaceous-Paleocene interval were deposited in a post-rift pelagic environment and are mainly biogenic with minimal terrigenous input. From the base up, they comprise black organic-rich sulphide-bearing argillite, black chert (silicified equivalent of the argillite), micritic with chert, and micrite rich in planktonic foraminifera. These passive-margin deposits are found regionally on the Norfolk Ridge down to New Zealand, and on the Lord Howe Rise, and were controlled primarily by regional or global environmental factors. The overlying Eocene deposits mark a change to an active-margin regime with distal calciturbidite and proximal breccia representing the earliest Paleogene flysch-type deposits in New Caledonia. The change from an extensional to a compressive regime marks the beginning of the pre-obduction convergence and can be assigned fairly accurately in the Koumac–Gomen area to the end of the Early Eocene (Late Ypresian, Biozone E7) at c 50 Ma. From this period on, the post-Late Cretaceous cover in northern New Caledonia was caught up and recycled in a southwest-verging accretionary complex ahead of which flysch was deposited in a flexural foreland basin. The system prograded southwards until the Late Eocene collisional stage, when the continental Norfolk ridge entered the convergence zone and blocked it. At this point the autochthonous and parautochthonous sedimentary cover and overlying flysch of northern New Caledonia was thrust over the younger flysch to the south to form a newly defined allochthonous unit, the ‘Montagnes Blanches’ nappe, that is systematically intercalated between the flysch and the obducted ophiolite units throughout Grande Terre.



2016 ◽  
Vol 67 (1) ◽  
pp. 41-68 ◽  
Author(s):  
Michal Francírek ◽  
Slavomír Nehyba

Abstract The Karpatian deposits of the central part of the Carpathian Foredeep in Moravia, which are deeply buried under the Outer Western Carpathians, provide a unique opportunity to reconstruct the former evolutionary stages of this peripheral foreland basin and its paleogeography. A succession of three depositional units characterized by a distinct depositional environment, provenance, and partly also foreland basin depozone, have been identified. The first depositional unit represents a proximal forebulge depozone and consists of lagoon-estuary and barred coastline deposits. The source from the “local” crystalline basement played here an important role. The second depositional unit consists of coastline to shallow marine deposits and is interpreted as a forebulge depozone. Tidalites recognized within this unit represent the only described tide-generated deposits of the Neogene infill of the Carpathian Foredeep basin in Moravia. The source from the basin passive margin (the Bohemian Massif) has been proved. The third depositional unit is formed by offshore deposits and represents a foredeep depozone. The provenance from both passive and active basin margin (Silesian Unit of the Western Carpathian Flysch Zone) has been proved. Thus, both a stepwise migration of the foredeep basin axis and shift of basin depozones outwards/cratonwards were documented, together with forebulge retreat. The shift of the foreland basin depozones more than 50 km cratonward can be assumed. The renewed thrusting along the basin’s active margin finally completely changed the basin shape and paleogeography. The upper part of the infill was deformed outside the prograding thrust front of flysch nappes and the flysch rocks together with a strip of Miocene sediments were superposed onto the inner part of the basin. The width and bathymetric gradient of the entire basin was changed/reduced and the deposition continued toward the platform. The basin evolution and changes in its geometry are interpreted as a consequence of the phases of the thrust-sheet stacking and sediment loading in combination with sea-level change.



2018 ◽  
Vol 470 (1) ◽  
pp. 311-336 ◽  
Author(s):  
Shawna E. White ◽  
John W. F. Waldron

AbstractWest Newfoundland was critical in developing the Wilson Cycle concept. Neoproterozoic rifting established a passive margin adjacent to the Iapetus Ocean. Ordovician (Taconian) arc–continent collision emplaced ophiolites and the thin-skinned Humber Arm Allochthon. Subsequent Devonian (Acadian) ocean closure produced basement-cutting thrust faults that control the present-day distribution of units. New mapping, and aeromagnetic and seismic interpretation, around Parsons Pond enabled the recognition of structures in poorly exposed areas.Following Cambrian to Middle Ordovician passive-margin deposition, Taconian deformation produced a flexural bulge unconformity. Subsequent extensional faults shed localized conglomerate into the foreland basin. The Humber Arm Allochthon contains a series of stacked and folded duplexes, typical of thrust belts. To the east, the Parsons Pond Thrust has transported shelf and foreland-basin units c. 8 km westwards above the allochthon. The Long Range Thrust shows major topographical expression but <1 km offset. Stratigraphic relationships indicate that most thrusts originated as normal faults, active during Neoproterozoic rifting, and subsequently during Taconian flexure. Devonian continental collision inverted the Parsons Pond and Long Range thrusts. Basement-cored fault-propagation folds in Newfoundland are structurally analogous to basement uplifts in other orogens, including the Laramide Orogen in western USA. Similar deep-seated inversion structures may extend through the northern Appalachians.



1992 ◽  
Vol 6 ◽  
pp. 165-165
Author(s):  
Susan M. Kidwell

Skeletal concentrations are common foci for paleontologic collecting, yet vary widely in their expected levels of taphonomic bias, particularly temporal resolution and biological fidelity. Basic concentration types include: (1) simple event-concentrations composed of anything from autochthonous-census, entirely exotic, or entirely remanié assemblages (e.g., shelly tempestites, shell-lined burrows); (2) composite concentrations of many stacked to complexly amalgamated events, accumulated in normal to expanded thickness (e.g., bioherms, shell banks & fans); (3) stratigraphically condensed hiatal concentrations having an even greater minimum degree of assemblage-level taphonomic bias (e.g., transgressive shelly sands, sediment-starved bone beds); and (4) lag-concentrations formed by erosion/corrosion of significant section and composed typically of highly culled and time-disordered skeletal material. Detailed field study of three temperate to subtropical basins in North America and reconnaissance of other basins at similar and lower paleolatitudes indicate that these four concentration types are distributed systematically within unconformity-bounded sequences and, moreover, that marine sequences vary qualitatively both in their stratigraphic anatomy (e.g. Van Wagoner et al., 1990; Einsele & Bayer, 1991) and skeletal taphonomy as a function of long-term subsidence.I. Basins of moderate subsidence (total 10's cm/ka maintained over 1–10 ma) are characterized by “textbook” sequences composed of discrete upward-shallowing parasequences in transgressive and highstand/regressive marine phases. Taphonomically, sequences in these settings typically contain a variety of concentration types, and therefore require careful taphonomic differentiation. In the shale-rich Cretaceous Ostracode Zone (Alberta foreland basin; Banerjee & Kidwell, 1991), for example, composite shell beds mark the tops of parasequences near the basin margin, event-beds of granulated shell mark the bases of parasequences further offshore, and diagenetically complex, shell-poor hiatal limestones mark maximum flooding surfaces in the most distal areas.II. Basins of high subsidence (total 100's cm/ka maintained over ≥1ma) are typically characterized by expanded sequences with vague parasequences; sedimentary cyclicity is linked more clearly to local tectonism and autocyclic environments than to eustasy. Taphonomically, these records are dominated by comparatively straightforward event- and composite concentrations. In the Mio-Pliocene Salton Trough (Gulf of California rift basin), for example, oyster bioherms and shell-ridges cap upward-shallowing delta-front cycles, and coral-bearing bioclastites occur along the distal toes of coastal alluvial fans and are banked against inter-fan rocky shorelines. Hiatal concentrations are poorly developed, even along downlap surfaces, and laterally extensive lags are rare.III. Basins of low subsidence (total ≤ few cm/ka maintained over 1–10 ma) are characterized by stratigraphically telescoped sequences with poorly developed (and locally deepening-up) “parasequences”; transgressive surfaces largely coincide with sequence boundaries. Hiatal and lag concentrations are relatively common and close-spaced stratigraphically; these may be taxonomically diverse even in temperate latitudes owing to environmental condensation, and in all instances are taphonomically complex. In the Miocene Chesapeake Group (outcropping U.S. Altantic passive margin), 4 transgressive hiatal shell concentrations lie within 40 m of section; each contains up to ~100 species and rests directly on a 3rd-order sequence boundary. A starved hiatal bone bed with high microplankton diversity marks the major 2nd-order downlap surface; lags of comminuted bones, teeth, and mollusk steinkerns mantle shallow-water unconformities near lap-out.



1998 ◽  
Vol 35 (11) ◽  
pp. 1271-1287 ◽  
Author(s):  
John WF Waldron ◽  
Scott D Anderson ◽  
Peter A Cawood ◽  
Laurel B Goodwin ◽  
Jeremy Hall ◽  
...  

The Humber Zone of the western Newfoundland Appalachians represents the early Paleozoic Laurentian margin established by Neoproterozoic rifting. After a period of passive margin thermal subsidence, Taconian deformation began in the Early Ordovician with westward thrusting. Subsequently, an extensive foreland basin developed beneath the Gulf of St. Lawrence. It records rapid Late Ordovician to Early Silurian subsidence; mid-Silurian erosion; and renewed Late Silurian to Devonian subsidence. The Humber Zone was traversed by Lithoprobe seismic reflection profiles. Within the external part of the orogen, seismic reflections in the upper crustal section appear more coherent where seismic lines are parallel to fold hinges. Some subhorizontal reflectors are interpreted as thrust sheets of shelf limestone, but others probably represent intrabasement structures. A group of moderately northwest-dipping reflections probably represents late extensional shear zones. On the Baie Verte Peninsula, low-angle reflections passing beneath the Baie Verte Line are probably also late extensional shears, possibly reactivating earlier thrusts. Tectonism in the Humber Zone probably began with attempted eastward subduction of the Laurentian margin. Deep burial of the margin, accompanied by eclogite-facies metamorphism, probably coincided with rapid subsidence in the foreland basin. Later Barrovian metamorphism was associated with cleavage development and east-directed shear, and with dextral oblique slip, in Baie Verte Peninsula. Later Silurian sinistral transpression with thrusting east of the Baie Verte Line was followed by dextral transpression to transtension. "Acadian" thrusting dominated the western margin of the orogen in the Devonian and possibly earliest Carboniferous.



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