摘要:

Geological evidence points to a Late PreCambrian origin for the Hormuz apatites associated with the red iron oxides, salt and other sedimentary and igneous rocks of the Hormuz Complex. Fission track dating of an apatite crystal from Hormuz Island gives an age of 55.4 ± 2.6 MM years for a cooling temperature of approximately 100d̀ C corresponding to the Paleocene‐Eocene boundary. This result is interpreted in the light of the burial and temperature history of the apatite associated with the Hormuz salt. It is concluded that the apatite clock registers the time elapsed since the temperature decreased to 100d̀ C at the Paleocene‐Eocene boundary. Steady cooling took place thereafter due to the continuing upward movement of the salt plug until Quaternary times. The stratigraphic position which the salt diapir (with the associated apatite) had reached 55 MM years ago corresponds to a level somewhere within the Triassic sequence. This would have been the zone of oil generation in Paleocene‐Eocene time, assuming that a source rock was present. Interpretational uncertainties are due to insufficient knowledge of the paleotemperature regime and of the stratigraphy and sedimentary thicknesses of the complete sequence down to the Precambrian. In addition, it is not possible to draw far‐reaching conclusions based on the dating of only

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00883.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

During secondary migration, the tendency towards a thermodynamic minimization of the hydrocarbon‐water interfacial energy can result in the confinement of petroleum in open fractures and coarser pores, in spite of the repeated conversion of gravitational energy into interfacial energy. A discussion of lithological influences leads to the prediction that migration in granular porosity is likely to end in trapping or dispersal, whereas migration in brittle, compact formations, which are little fractured, can allow the petroleum to reach distant structures.The source of supply for the “giant” tar accumulations of Alberta is then investigated. Chromatographic analyses strongly support a predominantly Triassic, basinal origin for the Pre‐Mesozoic Unconformity oils and, consequently, of the tars accumulated in the basal Cretaceous sands and Grosmont Paleozoic carbonates. A study of the spatial distribution of the thickness of oil‐stained rocks in the respective formations suggests that migration to the tar accumulations cannot have occured without interruption in the basal, transgressive Cretaceous sandstones, whereas continous migration (from the basin to the shelf) appears to have taken place in the weathered, carbonate Paleozoic

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00884.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

In a paper published in 1970, the Author expressed the view that the Mozambique Channel originated as Madagascar drifted to the NE from the Mozambique‐Natal coast. A further analysis of that view in the light of recently acquired data now enables him to formulate the hypothesis set out in this paper, namely that:(a). The geometry and tectonics of the Lebombo‐Zoutspansberg‐Buzi elongated fractures accompanied by Jurassic and Cretaceous effusives define a triple junction similar to the present‐day Red Sea‐Afar‐Gulf of Aden triple junction;(b). An initial rifting of the Channel occurred as the swell originating the triple junction produced a stretching of the continental crust and the initial separation of the Indo‐Malgache Landmass from Africa along the two eastern branches of the triple junction, while the middle one (Zoutspansberg) was being reduced to an abortive rift; and(c). Only when the thinned continental crust was stretched to the point of rupture did the oceanization process set in, with the production of “classical” spreading centres and magnetic anomalies.The latter process probably began in the Cretaceous, and was accompanied by impressive flows of alkaline lavas on the continental side and basalts in the oceanic area.Considering that, if this hypothesis is correct, the proto‐channel in Early Jurassic time was a narrow seaway, as suggested also by the juxtaposition of the major Mozambique and Madagascar fault lineaments; and considering that Madagascar has numerous shows and seepages of petroleum, probably of Jurassic age, the hypothesis discussed may have considerable bearing on the petroleum possibilities of the deeper Mozambican, Jurassic section, whose existence is indicated by several of the offshore seismic profiles recently run. Any oil generated in that section is likely to have migrated up‐dip on both sides

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00885.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Detailed geological and geochemical investigations in the folded belt of the Zagros geosyncline reveal that the source rocks for the very large Asmari oil accumulations may not be the PabdehGurpi and/or Kazhdumi formations as has been suggested; the hydrocarbons are more likely to be indigenous to the Asmari. Most previous investigators have assumed that only organic‐rich marls and shales serve as effective source rocks. However, geochemical analysis shows that the organic content of the Asmari carbonate, although not very rich, compares favourably with the source beds proposed by earlier workers.A rock should not be considered an oil source bed if it does not currently contain at least traces of oil. If the oil had been generated in the Pabdeh‐Gurpi and/or Kazhdumi formations, some hydrocarbons should still be present within these rocks.For all source rocks, there must be a positive relationship between thermal history and oil generation. Consequently, temperature and depth of burial are essential factors in petroleum genesis. The temperature history of the Asmari Formation is related to the thickness of the overlying Teritiary rocks. Maximum burial of the oligo‐Miocene Asmari, throughout most of the folded belt, is assumed to have occured during Early Pliocene time before the last phase of Zagros orogeny.Asmari limestone, therefore, qualifies as a source rock where it is buried deep enough to reach the optimum temperature needed to release its hydrocarbons. Under conditions of lower temprature and shallower burial, the limestones serve only as reservoir

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00886.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

In the first part of this presentation published in July(7, (3), 341–350), the Author proposed a scheme for the structural and tectonic evolution of the southern Himalayas. He now considers the model's constraints. The conclusions and references refer to both parts of the pape

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00887.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

An integrated analysis of the currently available geological and geophysical data in and around the Japan Sea indicaaaaaaes that the JapanBasin originated as a tectonic trough developed in an area of continental crust, a NE extension of the PreCambrian Ogcheon Trough on the Korean Peninsula.This conlusion is based on the following evidence: (1) tectonic trends recognized on the surrounding continents are basically traceable over the entire Japan Sea area; (2) the “sub‐oceanic” (“basaltic”) crust replaces all pre‐existing structures without conspicous horizontal displacement; (3) detailed submarine geologic maps show the predominance of vertical tectonics, which were controlled primarilyby makor‐deep seated fault systems coincide with linear magnetic anomalies and high heat‐flow zones, and are loci of volcanic activities; and (5) comparisonof geological and seismic data proves that the acoustic basement in the Japan Basin is provided bythe Paleozoic marine sediments, and not the “basaltic” layer as has hitherto been considered by many geoscientists.The above geological evidence conflicts with the plate‐tectonics or spreasing‐originhypotheses proposed by many authors. The linear magnetic anomalies generally coincide awithmajor fault zones and appear to show primary fracture patterns of the crust which interacted awith the upper mantle. Therefore, the validity of the linear magnetic anomalies as a criterion for determining spreading centres and rates is quesioned. The large discrepancy in structuralinterpertations derived, on the one hand, from a gephysical approach to the Japan Basin, and, on the other hand, from a geophysical approach, leads us to question whether the identification of continental and oceanic crust based on seismic refraaction data is valid.All the experience we have had in the controversy over the origin of the Japan Sea teaches us the following impotant lessons: (1) geological and geophsical studies need to be intergrated; and (2) detailed geological studies, especially geologic mapping of the continental shelf, the borderland, and submarine rises in close association with the mapped land geology, need to procede the discu

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00888.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The Hanifa Carbonate lithofacies (Upper Jurassic) started to develop during Early Kimmeridgian time, when an extensive area in central Arabia was covered by relatively deep marine waters. These rock units were formed along a shoreline, resulting in sucessive lagoonal and tidal‐flat belts, the deposition of pelleted and laminated calcilutites and gypsum, and a restricted fauna. The open shelf lay east of the lagoon zone, accounting for the development of oolites, coral reef and calcarenites, and a diversified fauna on the deeper shelf.At its maximum extent, the “Hanifa Sea” reached west nearly as far as the city of Riyadh in central Saudia Arabia, and extended NE and east, covering Kuwait, Iraq, Oman and Iran. South of Riyadh, the Hanifa lithofacies may be traced towards the SE over the Rub‐al‐Khali area, and SW over Yemen and the Aden Protectorates. North and NW of Riyadh, these same Upper Jurassic shallow‐marine rock units developed over Jordan, Syria, Lebanon, Palestine and northern Sinai, and most probably extended over northern Africa.Although the sediments forming the lower part of the Hanifa suggest that during Early Kimmeridgian tima a transgressive phase began, and most likely continued during part of the Middle Kimmeridgian, a regressive stage ensued towards the end of th Kimmeridgian, when the upper part of the Hanifa wa

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00889.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

A review of four simple techniques used to re‐orient conventional cores back to theri in‐situ position in presented. Cores can be oriented by:1Cutting oriented. cores;2Using dipmeters;3Re‐orienting in highly deviated holes;4Using remanent palaeomagnetism.The accuracy, costs and limitations of the methods are consi

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00890.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Book reviewed in this article:“World hydrocarbon markets: current status, projected prospects and future trench”, edited by M. S. Wionczek.“World natural gas outlook: what role for OPEC?”, by Bijan and Sharmin MossavarRahmani.“Introduction to the petroleum geology of the North Sea”edited by K. W. Glennie.“Geodynamics of the Eastern Pacific region, Caribbean and Scotia arcs”, edited by S. J. Ramon CabrePenn Well USA Oil Industry Directory, 23rd“The petroleum resources of Libya, Algeria and Egypt”“Rifts et fosses anciens (Ancient rifts and troughs)”, edited by M. Popoff and J. ‐J. Tiercelin.“The geology and hydrocarbon resources of Negara Brunei Darussalam”, edited by D. M. D. James.“Geological atlas of Western and Central Europe” by P. A. Ziegler.“Modelos deposicionales carbonaticos”, by A. V, Carrozzi.“Diccionario del Petrbleo Venezolano”, Ed. by A. R. Martinez.“Penn Well Map of World Sedimentary Basins and Related Features

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00892.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

ISSN:0141-6421    

DOI:10.1111/j.1747-5457.1984.tb00893.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY