bluuebunny/crossref_metadata_2025_split huggingface dataset:
GEOLOGIC MAP OF SOUTHERN HEMISPHERE
Authors: Mills R. A. 
Published: December 2007

A surface geologic map of the Southern Hemisphere should be useful to geologists and geophysicists studying continental drift and petroleum exploration because it relates Antarctic geology to the other continents.The most dominant feature appears to be the Transantarctic lineament that ties with the South American Andes and, to a lesser degree, with tectonic elements in eastern Australia. From the rocks exposed, it appears that Gondwanaland may have broken up during early Paleozoic time, and then the hemisphere remained stable until the end of Jurassic time when the existence of widespread volcanic rocks suggests that further rifting took place. During early Tertiary time, drifting was renewed and it more or less continued until recent time. Several island arcs and deep trenches indicate that rifting is still active today. There appears to be a significant west‐to‐east drift of crustal material at the far southern latitudes corresponding to the circum‐polar ocean currents.Offshore petroleum prospects are related to the age of the continental margins as determined by continental drift, i.e. the trailing edges of the continents have the most mature basins beginning with coastal plain sequences that are prograded over isostatically sinking margins. Thick sedimentary columns which began to form in the Mesozoic include reef facies and diapirs. There are exceptions to this model, and various offshore petroleum basins are described with emphasis on the exposed coastal plain morphology as providing the dominant indicator for large reserves.
CANADIAN HYDROCARBON RESOURCE DEVELOPMENT UP TO THE YEAR 2000
Authors: Teitz H. H. , Young F. G. 
Published: December 2007

Canada is blessed with numerous large and small sedimentary basins, both onshore and offshore, many of which have hardly been probed for their hydrocarbon potential. Only the most promising aspects of this potential can be highlighted in a brief review such as this, and hence the objectives of the report are (i); to present a regional assessment of the onshore and offshore basins in Canada and to document reservoir units for both conventional and non‐conventional hydrocarbon occurrences within the basin fills which may yield significant discoveries in the future (Map 1), and (ii) to emphasize Canada's political‐investment environment, and the roles of Petro‐Canada, Native Land claims, etc., since most, if not all, of the exploratory targets mentioned require large financial commitments and stable domestic and global conditions.Previous publications provided essential information to substantiate and/or alter views and projections expressed. Only summary papers are referred to in this review, and we apologize to authors whose views we have used but not acknowledged.
LOW‐RANK SEQUENCES AND SCALES OF ORGANIC METAMORPHISM
Authors: Suggate R. P. 
Published: December 2007

Degrees of alteration of carbonaceous material, when compared with scales of organic metamorphism, are used mainly by petroleum geologists for estimating conditions of development of sedimentary basins and for estimating the likelihood of oil and gas generation having taken place. For accurate estimation, especially of geological history, the scales need to be correctly designed, and low‐rank sequences (lignite, sub‐bituminous and high‐volatile bituminous ranks of coal) are critical for this. Scales need review, and data from surface and drillhole sequences in New Zealand are valuable for this. The generally‐accepted influence of time is considered unproved and unlikely to be significant.In order to relate the concept of “rank” to the geological conditions, it is necessary to use more than one parameter, and the best for use with low‐rank sequences are the dry‐basis calorific value and the bed moisture. Correlation of degrees of metamorphism with particular geological histories is not possible for high‐rank sequences.
GEOLOGIC TIME AS A PARAMETER IN ORGANIC METAMORPHISM AND VITRINITE REFLECTANCE AS AN ABSOLUTE PALEOGEOTHERMOMETER
Authors: Price Leigh C. 
Published: December 2007

Substantial published and unpublished data contradict accepted laws of organic metamorphism. Significant amounts of C15+ hydrocarbons and kerogen with significant generation potential exist in sediments which have been buried at high temperatures for long periods of geologic time. Graphite formation and greenschist metamorphism do not occur at model‐predicted burial times and temperatures. Maturation levels for sediments with long (up to 240 million years) burial times are much lower than expected, and conversely, higher than expected for sediments with short (2 million years) burial times. The threshold of intense petroleum generation is not detectable in Plio‐Miocene sediments at minimum temperatures of 160° C.Literature examination reveals that the only solid documentation of time as a controlling parameter in organic metamorphism is in the works of Karweil (1955), Lopatin (1971) and Connan (1974). Scrutiny of these authors' study areas reveals that all have had moderate to extreme paleogeothermal gradients from incipient and aborted rifting, extrusive and intrusive igneous activity, hydrothermal activity, orogenesis and/or uplift and erosion. Levels of organic metamorphism attributed to geologic time by the above authors are better explained by high paleogeothermal gradients resulting from major geologic activity.Mean vitrinite reflectance (RO) data have been compiled from different sedimentary basins currently at or near maximum geothermal gradients with sediment burial times ranging from 2–240 million years. The RO data from these basins show a strong correlation (r = 0.97) of increase in R, with increase in temperature. These same data show no correlation of increasing Ro with increasing burial times for any temperature interval. R, data from sedimentary basins affected by high‐temperature geothermal systems with heating times of only 1,000–10,000 years overlie R, data from these petroleum‐bearing sedimentary basins with burial (heating) times of 2–240 million years.Contrary to accepted thought, there is no evidence from the natural system that petroleum generation‐maturation reactions have first‐order reaction kinetics. By contrast, a substantial body of evidence from petroleum generation‐maturation laboratory studies carried out in closed water‐ wet systems show that these reactions are characterized by multiple‐order reaction kinetics.Geologically older sediments clearly tend to be more organically mature than younger sediments at the same burial temperatures. However, this correlation ismorea reflection that older sediments have had a greater chance of being affected by a major geologic event with an accompanying high heat flow. The major conclusions of this paper are that: (1) geologic time has no observable effect on organic metamorphism; (2) vitrinite reflectance can be used as an absolute paleogeothermorneter; and (3) the accepted models of organic metamorphism at the very least need substantial revision.
ORGANIC MATIXR CONTENT IN CARBONATE SEDIMENTS IN RELATION TO PETROLEUM OCCURRENCE
Authors: Ibe A. C. , Ferguson J. , Kinghorn R. R. F. , Rahman M. 
Published: December 2007

Analyses of recent carbonate sediments of a wide variety of textural types reveal organic carbon content of 0.98–5.23 wt.% which are well above the 0.3 wt.% minimum requirement for carbonate sediments to be considered potential source deposits.The organic facies consist dominantly of autochthonous marine organic matter, both particulate and dissolved, which is highly pyrolysis‐degradable. Under the correct conditions of burial, temperature and probably catalysis (despite the general absence of clays), commercially‐significant hydrocarbons would be generated and would accumulate as petroleum in those rocks that possess the necessary effective porosity.This concept of the origin of petroleum in carbonate rocks affords an explanation for the exceptionally rich petroleum accumulations in porous carbonate rocks; it is also consistent with the stratigraphic habitats of most hydrocarbon pools in carbonate petroliferous provinces.
SOME CONTEMPORARY PROBLEMS OF PETROLEUM GEOLOGY IN KUWAIT: A MIDDLE EAST EXAMPLE
Authors: Ibrahim M. W. 
Published: December 2007

Paradoxical as it may seem, Kuwait is part of one of the least explored oil‐producing regions on Earth. Contrary to common misconceptions, it has yet to complete the exploration of its hydrocarbon resources.Due to various factors, a few local and scanty regional studies of the petroleum geology of Kuwait have now been completed by various establishments. Regional studies were based mainly on unevenly distributed and widely spaced control points. They invariably recommended further studies.It stands to reason that future regional studies should adopt an alternative approach, or otherwise end‐up with similar conclusions.
VARIATIONS IN TECTONIC STYLES IN THE ZAGROS GEOSYNCLINE AND THEIR RELATION TO THE DIAPIRISM OF SALT IN SOUTHERN IRAN
Authors: Kashfi Mansour S. 
Published: December 2007

A study of the surface and subsurface geology of the Zagros mountain belt reveals that, from the viewpoint of tectonic fabrics and the cause of diastrophism, the Zagros geosyncline can be divided into NW and SE segments. The NW segment was formed by orogenic compression and the SE segment primarily by epeirogenic uplifts. Movements of Infra‐Cambrian (Hormuz) salt at the base of the sedimentary column in the SE Zagros contributed to the epeirogenesis. Faults in the SE Zagros are of a normal type, whereas in the NW Zagros they are dominantly thrust. Seismic data indicate that movement of salt is the cause of many of the earthquake shocks in the SE Zagros.Hydrocarbons in the SSE Zagros either escaped through fractures within exposed reservoirs or migrated while epeirogeny was proceeding to be trapped in the western flank of the Oman high in the extreme SE portion of the Zagros belt.
THE PETROLOGY OF THE MIDDLE JURASSIC SANDSTONES FROM THE MURCHISON FIELD, NORTH SEA
Authors: Morton A. C. , Humphreys B. 
Published: December 2007

A petrographical investigation of the sandstones of the Brent Group (Middle Jurassic) from the Murchison field has produced evidence for the existence of two transgressive events within the sequence, one occurring immediately above the Etive Fm., the other within the upper part of the Ness Fm. These transgressions have not been previously recorded in Murchison and their discovery demands that some modification be made to the existing depositional model for the Brent Group of this area. A volcanic ash horizon has been found in a similar stratigraphic position to that recorded from Statfjord, and if this, and the two transgressive horizons noted above, are of more than local extent they could prove to be useful stratigraphic markers.Although the diagenesis of the Brent Group sandstones in Murchison differs little from that recorded elsewhere in the Brent province, the interpretation of the timing of the development of certain phases differs somewhat from those of other authors. In particular, kaolinite development appears to have taken place soon after burial in response to periods of emergence and weathering during Brent Group deposition, rather than through groundwater circulation during the Kimmerian tectonic phase.
SEDIMENTOLOGICAL AND PALEONTOLOGICAL ANALYSIS OF JURASSIC NORTH SEA DEPOSITS FROM DELTAIC ENVIRONMENTS
Authors: Nagy J. , Dypvik H. , Bjaerke T. 
Published: December 2007

Core samples from Well 33/9‐3, Norwegian North Sea, have been analysed sedimentologically, palynologically and micro‐paleontologically. The cores cover the Toarcian Drake Member of the Dunlin Formation, and nearly the whole thickness of the Middle Jurassic Brent Formation.The Drake Member is characterized by pro‐deltaic depositional conditions. In the Brent Formation, five members are recognized (from below): the Broom, Rannoch and Etive Members represent distributary mouth bar facies; while the Ness and Tarbert Members are recognized as interdistributary bay fill sequences.The composition of the kerogen assemblages is controlled by the changing energy regimes of the different depositional facies. Terrestrial plant débris are dominant throughout the studied interval. Marine palynomorphs are present in the Drake Member and in the lower part of the Broom Member. The development of rich, arenaceous foraminiferal assemblages in the Drake Member are interpreted as a response to shallow, pro‐deltaic conditions. Calcareous foraminifera constitute only a small, accessorial part of these assemblages.
THE JAPAN BASIN ‐ A TECTONIC TROUGH
Authors: Choi Dong Ryong 
Published: December 2007

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 discussion of any hypothesis.
SUPPRESSION OF VTRINITE REFLECTANCE IN AMORPHOUS RICH KEROGEN ‐ A MAJOR UNRECOGNIZED PROBLEM
Authors: Price Leigh C. , Baker Charles E. 
Published: December 2007

Vitrinite reflectance (Ro,) is regarded as one of the most, ifnot the most, powerfultools available to petroleum organic geochemistry. Yet major recognized and unrecognized problems exist concerning use of the technique. One such unrecognized problem is a major suppression of Ro by significant concentrations of exinite macerals (Type I and Type II kerogen) in association with vitrinite macerals.Ro values have been, and are, for the most part, read from exinite‐rich sediments examined in organic geochemical studies. This has led to the establishment of R0 values of 0.6 (± 0.1) and 1.35 corresponding, respectively, to the regional rank necessary for the onset of significant hydrocarbon generation and for the thermal destruction of petroleum (“oil deadline”). These uniformly quoted Ro values, derived from exinite‐rich (hydrogen‐rich) kerogens, would have far different values if Ro had been read from vitrinite‐rich (oxygen‐rich) kerogen at the same regional rank. The serious miscalibration of the regional ranks necessary for the onset of significant petroleum generation from exinite‐rich kerogen and for the “oil deadline” have major implications for assessment of frontier areas of possible petroleum reserves as well as for petroleum exploration in general and worldwide and basin‐by‐basin resource assessment of undiscovered petroleum reserves.
EVAPORITES AS OIL AND GAS SOURCE ROCKS
Authors: Sonnenfeld Peter 
Published: December 2007

Shale‐ and micritic limestone‐bound organics have long been considered as hydrocarbon source rocks. However, a conceptual model of hydrocarbon generation in salt basins does not require the entrapment of hydrocarbons in impervious strata, shales or micritic limestones as source rocks.In evaporite basins, organic matter derived from surface waters is preserved beneath the pycnocline of a density‐stratification in anaerobic hypersaline bottom brines. Not being recycled, it is decomposed by bacteria, goes into solution or settles on the bottom. Montmorillonites, calcites, gypsum and potash deposits can alter organic matter catalytically. Impervious clays and micritic limestones trap large hydrocarbon molecules permanently; smaller molecules are flushed through a permeable substrate into aquifers and delivered to reservoirs. After burial, maturation equal to other hydrocarbons is achieved at a lower vitrinite index.
KEROGEN FACIES IN THE MAJOR JURASSIC MUDROCK FORMATIONS OF SOUTHERN ENGLAND AND THE IMPLICATION ON THE DEPOSITIONAL ENVIRONMENTS OF THEIR PRECURSORS
Authors: Ebukanson E. J. , Kinghorn R. R. F. 
Published: December 2007

Kerogen types and their hydrocarbon‐generating potentials in three main mudrock units in the Jurassic of Southern England ‐ the Lower Lias, the Oxford Clay and the Kimmeridge Clay ‐ have been investigated using elemental analysis, transmitted‐light microscopy, density fractionation and pyrolysis‐gas chromatography. The results show that, as with the lithology, the three formations display variations in their kerogen composition. The kerogen facies range from the chemical Type II to Type IV in the Lower Lias and the Oxford Clay, whereas only Types II to III are identified in the Kimmeridge Clay. Amorphous organic material constitutes the most abundant fraction of all the kerogen samples. All the identified kerogen types show a potential for generating both oil and gas.The fluctuating oxic‐anoxic depositional bottom conditions during the Jurassic is suggested to have been the major factor controlling the distribution of kerogen facies in the three formations.
HYDRODYNAMIC FRAMEWORK OF THE PETROLEUM RESERVOIRS AND CAP ROCKS OF THE MESOPOTAMIAN BASIN OF IRAQ
Authors: Al‐Mashadani Ali 
Published: December 2007

The basic mechanisms governing the hydrodynamic patterns in sedimentary basins are ultimately related to the pressure, reservoirs, water salinity and chemical composition, and the regional geological environment, all of which are interdependent. In Iraq, there are four major hydrogeological units in the Tertiary‐Jurassic section, which are generally governed by two hydrodynamic systems — by gravity and by high‐pressure zones.1. Slightly saline water moves by the action of gravity from sites of high potential, namely the Zagros foothills zone and the outcrops of the Arabian shield (where reservoirs are recharged) towards the centre of the basin, which is topographically low. The Tigris, Euphrates and Arabian Gulf form a drainage axis due to their comparatively low topographic positions.The vertical movement of formation water in the basinal area where artesian phenomena exist is effectively possible, favoured by major faults and fractures connecting the deep aquifers to the surface. This mechanism is even more notable in areas of minimum potential.2. High pressure zones have their origin in the diagenesis of organic matter and “cracking” of hydrocarbons beneath thick sediments, which lead to an increase in pressure within a closed system. Abnormally high pressures have been encountered in the Lower Cretaceous in Southern Iraq, mostly related to the presence of gas.Pressure anomalies may also be related to the compaction of sedimentary rocks; if during compaction the fluid expulsion can be normally effected due to the presence of satisfactory drainage channels, the hydraulic gradients will be low. On the other hand, if the fluid expelled is drained into a confined reservoir embedded within argillaceous beds, then an abnormally high pressure will be created.The hydrodynamic systems are related to the geometry of the sedimentary basin; in addition, factors other than compaction (for example, the existence of Miocene saliferous beds, tectonic forces, temperature, etc.) may be involved in the development of high pressures in the Tertiary aquifers of the north and NE of the Mesopotamian basins.The salt series of the Hormuz and Gotnia formations encountered in the Arabian Gulf, which extend to Southern Iraq, could be one of the factors related to the pressure anomalies, when they remain within a closed system.The hydrodynamic systems and the geodynamic evolution of the sedimentary rocks are responsible for the confined formation water, the migration of expelled water towards the surface, and the distribution within the basin of various parameters such as the hydraulic potential, salinity, heat flow, and diagenesis.
MATURITY OF ORGANIC MAITER IN THE JURASSIC OF SOUTHERN ENGLAND AND ITS RELATION TO THE BURIAL HISTORY OF THE SEDIMENTS
Authors: Ebukanson E. J. , Kinghorn R. R. F. 
Published: December 2007

An investigation of the maturity levels of organic matter in the major potential Jurassic hydrocarbon source rock units in Southern England (i.e. the Lower Lias, Oxford Clay and Kimmeridge Clay) using sporomorph colouration and alkane distribution patterns shows that the Oxford Clay and the Kimmeridge Clay organic materials are immature in most parts of the area. They are mature only in the central parts of the Mesozoic Wealden Basin.The distribution of mature Lower Lias sections is found to be more extensive. Attempted reconstruction of the burial histories of Jurassic sections across Southern England, and the application of the Lopatin method of theoretical organic maturity prediction, seem to support the observed maturity trends and suggest that the present maturity levels of Jurassic organic matter at any given locality are dependent on the structural development of that area through time.
A JURASSIC DELTA IN THE EASTERN ALBORZ, NE IRAN
Authors: Rad F. K. 
Published: December 2007

A clastic dominated Lower‐Middle Jurassic sequence, known as the Shemshak Formation, is extensively exposed in the Eastern Alborz area, NE Iran. The unit represents a deltaic complex sandwiched between carbonate rocks. Sedimentological study of the formation outcrops has revealed that it was deposited in environments ranging from subaerial to subaqueous delta plains.Potential source, reservoir and cap rocks are present within the Shemshak Formation; under favourable conditions, generation and accumulation of hydrocarbons in significant quantities can be envisaged. It is suggested that the Shemshak delta, buried under the thick Neogene sediments in the Eastern Alborz area, is a highly prospective exploration target with potential for a multipay section.