Le Flysch gaditan au nord et au nord-est d'Algesiras (prov. de Cadix, Espagne)

1960 ◽  
Vol S7-II (3) ◽  
pp. 352-361
Author(s):  
Jean Didon
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Upper Eocene ◽  
The West ◽  
Upper Oligocene

Abstract Several allochthonous units were discovered during geologic reconnaissance in 1958-59 north and northeast of Algeciras, Spain. At the base is the Estepona Flysch, comprising upper Oligocene and Miocene deposits. Above this are the Algeciras unit, consisting of upper Eocene and Oligocene Flysch deposits, and the Camarote unit, composed of Tithonian (Jurassic) and lower Cretaceous sandy marls. At the top are the Aljibe sandstone on the west (Oligocene) and the Argueelles unit on the east (upper Cretaceous to middle Oligocene limestones). Most of these units originated in Ultrabetic regions.

GEOLOGY AND PETROLEUM PROSPECTS OF RUATORIA AREA, EAST COAST, NORTH ISLAND, NEW ZEALAND.

1972 ◽  
Vol 12 (1) ◽  
pp. 45
Author(s):  
A.C.M. Laing
Keyword(s):  
New Zealand ◽  
Upper Cretaceous ◽  
East Coast ◽  
Geological Mapping ◽  
Upper Eocene ◽  
Upper Miocene ◽  
Upper Oligocene ◽  
Potential Reservoir ◽  
Surface Geology ◽  
Shallow Structure

As measured in outcrop sections, more than 30,000 ft. (9,000 m.) of Upper Cretaceous and Tertiary marine sediments overlie basement of Lower Cretaceous age in the area. Mudstones, siltstones, and turbidites make up the majority of this sedimentary section but there are also 3,000 ft. (900 m.) of interbedded greywacke sandstones and siltstones of Maestrichtian age, and 400 ft. (120 m.) of interbedded limestone and greensands of Oligocene age. Both of these latter units are potential reservoir beds.The majority of the exploration work has been by surface geological mapping. A number of time-rock units have been used which were initially distinguished by fossils, but which could later be distinguished by lithological differences.Four regional unconformities, base of Upper Cretaceous, near top of Upper Cretaceous, Upper Oligocene, and Upper Miocene have been recognised in the stratigraphic section.A slump breccia of Upper Eocene age has also been mapped extending over an area 25 mi. (40Km) by 5 mi. (8Km) with a maximum thickness of 7500 ft. (2.25Km.) and contains large lumps of older rocks. The sediments of the Ruatoria area are folded into broad synclines and tight anticlines with average dips ranging from 50 degrees in the Upper Cretaceous to 15 degrees in the Upper Miocene. The trend of the folds is northeast in the southern part of the area and northwest in the northern part, the dividing line being the major northwest trending Hikurangi Fault.The area abounds in gas seepages some of which have been capped and exploited. There are records of oil seepages also. Within the 453 sq.mi. (1,178 sq. Km) only nine shallow holes have been drilled all of which recorded some oil or gas shows.Alliance Petroleum has located two wells on the flanks of closed structures outlined by surface geology and shallow structure drilling.

Le Cretace superieur et le Paleogene dans la dorsale calcaire aux abords meridionaux de Tetouan (Rif septentrional, Maroc)

1964 ◽  
Vol S7-VI (3) ◽  
pp. 305-308
Author(s):  
Jean Claude Griffon ◽  
J. Magne ◽  
Jacques Sigal
Keyword(s):  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Upper Eocene ◽  
Tectonic Movements

Abstract The limestone dorsal of the northern part of the Rif mountains near Tetuan, Morocco, exposes Permian clastics, Triassic dolomite, Jurassic and lower Cretaceous limestone, upper Cretaceous to Eocene marl, transgressive upper Eocene conglomerate, and Oligocene flysch. The microfauna of the upper Cretaceous and the Paleogene formations are particularly useful in correlations. Major tectonic movements occurred in the Miocene.

CONTINENTAL SHELF BASINS ON THE WEST TASMANIA MARGIN

1992 ◽  
Vol 32 (1) ◽  
pp. 231 ◽  
Author(s):  
A.M.G. Moore ◽  
J.B. Willcox ◽  
N.F. Exon ◽  
G.W. O'Brien
Keyword(s):  
Continental Shelf ◽  
Continental Slope ◽  
Late Cretaceous ◽  
Lower Cretaceous ◽  
Upper Cretaceous ◽  
Strike Slip ◽  
Source Rocks ◽  
Fault System ◽  
The West ◽  
Shallow Marine

The continental margin of western Tasmania is underlain by the southern Otway Basin and the Sorell Basin. The latter lies mainly under the continental slope, but it includes four sub-basins (the King Island, Sandy Cape, Strahan and Port Davey sub-basins) underlying the continental shelf. In general, these depocentres are interpreted to have formed at the 'relieving bends' of a major left-lateral strike-slip fault system, associated with 'southern margin' extension and breakup (seafloor spreading). The sedimentary fill could have commenced in the Jurassic; however, the southernmost sub-basins (Strahan and Port Davey) may be Late Cretaceous and Paleocene, respectively.Maximum sediment thickness is about 4300 m in the southern Otway Basin, 3600 m in the King Island Sub-basin, 5100 m in the Sandy Cape Basin, 6500 m in the Strahan Sub-basin, and 3000 m in the Port Davey Sub-basin. Megasequences in the shelf basins are similar to those in the Otway Basin, and are generally separated by unconformities. There are Lower Cretaceous non-marine conglomerates, sandstones and mudstones, which probably include the undated red beds recovered in two wells, and Upper Cretaceous shallow marine to non-marine conglomerates, sandstones and mudstones. The Cainozoic sequence often commences with a basal conglomerate, and includes Paleocene to Lower Eocene shallow marine sandstones, mudstones and marl, Eocene shallow marine limestones, marls and sandstones, and Oligocene and younger shallow marine marls and limestones.The presence of active source rocks has been demonstrated by the occurrence of free oil near TD in the Cape Sorell-1 well (Strahan Sub-basin), and thermogenic gas from surficial sediments recovered from the upper continental slope and the Sandy Cape Sub-basin. Geohistory maturation modelling of wells and source rock 'kitchens' has shown that the best locations for liquid hydrocarbon entrapment in the southern Otway Basin are in structural positions marginward of the Prawn-1 well location. In such positions, basal Lower Cretaceous source rocks could charge overlying Pretty Hill Sandstone reservoirs. In the King Island Sub-Basin, the sediments encountered by the Clam-1 well are thermally immature, though hydrocarbons generated from within mature Lower Cretaceous rocks in adjacent depocentres could charge traps, providing that suitable migration pathways are present. Whilst no wells have been drilled in the Sandy Cape Sub-basin, basal Cretaceous potential source rocks are considered to have entered the oil window in the early Late Cretaceous, and are now capable of generating gas/condensate. Upper Cretaceous rocks appear to have entered the oil window in the Paleocene. In the Strahan Sub-Basin, mature Cretaceous sediments in the depocentres are available to traps, though considerable migration distances would be required.It is concluded that the west Tasmania margin, which has five strike-slip related depocentres and the potential to have generated and entrapped hydrocarbons, is worthy of further consideration by the exploration industry. The more prospective areas are the southern Otway Basin, and the Sandy Cape and Strahan sub-basins of the Sorell Basin.

Pteropods (Mollusca: Gastropoda) from Tertiary formations of Washington and Oregon

1989 ◽  
Vol 63 (4) ◽  
pp. 443-448 ◽  
Author(s):  
Richard L. Squires
Keyword(s):  
United States ◽  
Deep Water ◽  
West Coast ◽  
Middle Miocene ◽  
The United States ◽  
Western Hemisphere ◽  
Upper Eocene ◽  
The West ◽  
Upper Oligocene ◽  
First Time

Praehyalocylis cretacea (Blanckenhorn, 1889), a pteropod previously known only from upper Eocene to middle Miocene strata in Europe and Turkey, is reported for the first time in similar age rocks in the northwestern United States. Of the 238 specimens, most occur as molds and casts in concretions in deep-water deposits from the Keasey Formation in Oregon, and from the Quimper Sandstone, Blakeley Formation, Pysht Formation, and Astoria Formation of Washington. Praehyalocylis has not been reported previously from the Western Hemisphere.Clio berglundi n. sp. and C. goederti n. sp. are reported from upper Oligocene to lower Miocene rocks in Washington. Eleven specimens were found mostly as internal molds in concretions in deep-water deposits of the Lincoln Creek, Pysht, and Astoria Formations of Washington. Cenozoic species of Clio have not been reported previously from the West Coast of the United States.

Apercu geologique sur les collines de Boutenac (Aude)

1962 ◽  
Vol S7-IV (3) ◽  
pp. 362-379
Author(s):  
Alain Combes
Keyword(s):  
Upper Cretaceous ◽  
Upper Triassic ◽  
Normal Faulting ◽  
The West ◽  
Southern France ◽  
Sandy Limestone

Abstract The Boutenac hills in the northeastern Corbieres region of southern France, are part of the autochthonous foreland of the eastern Corbieres nappe. They are an isolated massif between the Paleozoic formations of the Alaric mountain on the west, and the Jurassic and Cretaceous formations of the Fontfroide chain on the east, entirely surrounded by alluvium. Structurally, they comprise Mesozoic formations on the east thrust over the Eocene on the west, on a fault that is the prolongation of the Saint Chinian frontal fault to the northeast. The Mesozoic formations comprise upper (?) Triassic shale and dolomite, sandy limestone, dolomite, and limestone; Jurassic red sandstones and shales; and upper Cretaceous transgressive clastics. The Eocene is limestone and marl overlain by continental conglomerate and molasse, transgressive on the west upon the Alaric Paleozoics. Folding and thrust and normal faulting are important in the structure.

scholarly journals Types of river sources of the thin-grained aluminosilicaclastics for the Jurassic and lower cretaceous deposits of the West Siberian megabasin

2021 ◽  
Vol 63 (4) ◽  
pp. 52-61
Author(s):  
A. V. Maslov
Keyword(s):  
Lower Cretaceous ◽  
The Urals ◽  
River Systems ◽  
The West ◽  
Rock Composition ◽  
Fine Grained ◽  
The North ◽  
Catchment Areas ◽  
Cretaceous Deposits ◽  
West Siberian Basin

Background. The lithogeochemical features of fine-grained detrital rocks (mudstones, shales, and fine-grained siltstones) allow, with a certain degree of success, the main parameters of the formation of sedimentary sequences to be reconstructed. These parameters include (primarily in terms of their REE and Th systematics) the types of river systems supplying thin terrigenous suspension in the sedimentation area: the rivers of the 1st category – large rivers with a catchment area of more than 100,000 km2; 2nd category – rivers feeding on the products of erosion of sedimentary deposits; 3rd category – rivers draining mainly igneous and metamorphic rocks; and 4th category – rivers carrying erosion products of volcanic associations.Aim. To reveal, based on the analysis of interrelationships between such parameters as (La/Yb)N, Eu/Eu* and the Th content, the types of river systems that fed the Jurassic and Lower Cretaceous deposits of the Shaim oil and gas region (OGR) (Sherkalinsky, Tyumen, Abalak and Mulymya formations) and the region of the North Pokachevsky field of the Shirotnoe Priobye region (Sherkalinsky, Tyumen and Bazhenov formations, Lower Cretaceous deposits).Materials and methods. The ICP MS data for almost 100 samples of mudstones and fine-grained clayey siltstones were used to analyse the features of distribution of lanthanides and Th in the Jurassic and Lower Cretaceous clayey rocks of the Shaim OGR and the area of the North Pokachevsky deposits. Individual and average composition points for formations, members and layers were plotted on the (La/Yb)N-Eu/Eu*, (La/Yb)N–Th diagrams developed by us with classification areas of the composition of fine suspended material of modern rivers of different categories.Results and conclusion. The results presented in the article showed that during the formation of the deposits of the Shaim OGR in the Early and Middle Jurassic, erosion affected either mainly sedimentary formations or paleo-catchment areas that were very variegated in their rock composition. In the Late Jurassic, the source area was, most likely, a volcanic province, composed mainly of igneous rocks of the basic composition, and located within the Urals. This conclusion suggested that the transfer of clastic material from the Urals to the Urals part of the West Siberian basin “revived” much earlier than the Hauterivian. The Jurassic-Lower Cretaceous section of the vicinity of the North Pokachevsky field was almost entirely composed of thin aluminosilicaclastics formed due to the erosion of volcanic formations. These volcanic formations were located, as followed from the materials of earlier performed paleogeographic reconstructions, probably within the Altai-Sayan region or Northern Kazakhstan. Thus, the supply of detrital material in the considered territories of the West Siberian basin had a number of significant differences in the Jurassic and early Cretaceous.

scholarly journals V.—Note on an Undescribed Area of Lower Greensand or Vectian in Dorset

1891 ◽  
Vol 8 (10) ◽  
pp. 456-458 ◽  
Author(s):  
A. J. Jukes-Browne
Keyword(s):  
Lower Cretaceous ◽  
Small Area ◽  
Upper Cretaceous ◽  
The Other ◽  
Present Communication ◽  
The Subject ◽  
Geological Magazine

Until recently no outcrop of the Vectian or Lower Greensand was known to occur between Lulworth on the coast of Dorset and the neighbourhood of Devizes in Wiltshire. It was supposed that, with the exception of a small area of Wealden in the Vale of Wardour, the whole of the Lower Cretaceous Series in Dorset and South Wilts was concealed and buried beneath the overlapping Upper Cretaceous strata. A recent examination of this district however has revealed two areas where the Vectian sands emerge from beneath the Gault. One of these has already been indicated in the pages of the Geological Magazine; the other is the subject of the present communication.

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