bluuebunny/crossref_metadata_2025_split huggingface dataset:
Soft contact lens wear in Hong Kong‐Chinese: predicting success*
Authors: Chui Wan Sang , Cho Pauline , Brown Brian 
Published: December 2007

SummaryThe tear stability and tear volume of 55 asymptomatic Hong Kong‐Chinese were assessed before soft contact lens (Hydron Zero 6) wear and repeated on three visits over 28 weeks of lens wear. Soft lens wear caused a significant initial transient decrease in the non‐invasive tear break‐up time (NITBUT), but no change in tear volume as assessed by the self‐prepared cotton thread test (SP‐CTT) and phenol red thread (PRT) test. After 28 weeks, the subjects were classified according to the length of time they could wear their lenses without dry eye related signs and symptoms. The NITBUT and PRT tests were unable to predict the success of soft contact lens wear. However, the SP‐CTT gave a sensitivity and specificity of 88.5 and 52.4%, respectively, in the prediction of subjects most likely to be successful wearers. The positive and negative predictive values at the chosen cut‐off point were 69.7 and 78.6%, respectively. Wetting values, that is, combinations of NITBUT and SP‐CTT values or NITBUT and PRT values, did not predict success in soft contact lens wear.
Step‐along vergence procedures in stigmatic and astigmatic systems
Authors: Harris W. F. 
Published: December 2007

SummaryThe traditional step‐along vergence procedure applies to stigmatic systems, that is, systems that are not astigmatic. Computation is disrupted when a focus coincides with a thin lens or refracting surface. A small change to the procedure results in a modified procedure which overcomes the computational problems. The modified procedure is easier to execute than the traditional procedure and allows one to write down useful equations directly. Among the formulae are those for back‐vertex power. A step‐along vergence procedure also exists for astigmatic systems. It makes use of the dioptric power matrix and the reduced vergence matrix. Computational problems arise when a point or line focus coincides with a thin lens or refracting surface; however they are not overcome by an analogous modification to the procedure. Nevertheless the modified procedure has some advantages including the fact that, as for stigmatic systems, it allows one to write down useful formulae directly. Stepwise calculations of vergence are sometimes performed backward through a system; the advantages and disadvantages described for step‐along procedures holds for such step‐back procedures as well.
USE OF FORELAND MONITORS IN THE CORRELATION AND ANALYSIS OF OROGENIC PULSES
Authors: Wilson H. H. 
Published: December 2007

Theories on crustal evolution have been developed from geologic investigations in orogenic belts and in the less deformed foreland or epeirogenic areas. In this paper, it is suggested that, because one global mechanism must govern the evolution of both orogenic and epeirogenic areas, the two must be closely related. Because the interpretation of orogenic belts is complicated so greatly by extreme deformation, metamorphism, and loss of data through erosion, it is logical to seek interpretative leads on their orogenic style and timing by precise observations and analyses of structural “monitors” in the less complex borderlands.The three foreland monitors considered are: (1) block faulting, (2) salt diapirism, and (3) volcanicity. All three monitors support the concept that tectonic pulses during measurable geologic time have been short lived and synchronous around the globe. They also indicate that the dominant structural stress which triggered these tectonic pulses has been extensional.If extensional stress also has governed the evolution of orogenic belts, then the interpretations which advocate fundamental vertical tectonics, secondary gravity sliding, and intrusion by mantle diapirism are more acceptable than those which advocate crustal shortening and compression. Moreover, if tensional tectonics has governed both orogenic and epeirogenic areas as well as the ocean‐spreading centers, then the hypothesis of global expansion is more logical and harmonious than the popular and heuristic assumptions on crustal subduction.For the successful resolution of regional tectonic problems, geologists must free themselves of dogmatic constrictions and broad generalisations. As in the exploration for hydrocarbons, what is needed is a scrupulous and patient attention to geologic detail, set within the most precise time framework attainable.
FLOOD BASALTS: IMPLICATIONS FOR GLOBAL‐TECTONIC HYPOTHESES AND PETROLEUM EXPLORATION
Authors: Kamen‐Kaye Maurice , Meyerhoff A. A. 
Published: December 2007

Present geodynamic models treat the continents and ocean basins as separate tectonic domains, whereas the few coordinated attempts to extend continental geology into the deep marine basins, and vice versa, suggest that the two domains may not be so easily distinguished. Flood‐basalt provinces provide one striking example of the great similarity between parts of some continents and the deep‐sea floor. In at least two areas, continental flood basalts can be traced directly into the oceanic realm. Because of this, modern geodynamic models may have to be revised.Flood basalts also can be associated with petroleum occurrences. Three examples include the discovery of gas beneath Jurassic basalts off north western Australia, of oil beneath Late Jurassic or early Cretaceous basalts off Ghana, and of gas and oil beneath Jurassic to Triassic sills in the Middle and Upper Amazon basins of Brazil.
THE GENESIS OF THE ZOHAR GAS AS DEDUCED FROM ITS CHEMICAL AND CARBON ISOTOPE COMPOSITION
Authors: Amit Ora , Bein Amos 
Published: December 2007

The hydrocarbon compositions (C1/ΣC1—C4) = 0.96‐0.98) and the carbon isotopes ratios of methane (—51.4 to—52.1%) studied in the Zohar Gas Field indicate that the generations of the gas was associated with an oil‐generation process. Thus, gas and heavy oils found in the area could have formed simultaneously within one system.The carbon isotope composition of the CO2 is relatively heavy, with δ13 CO2 value ofabout +7% which is probably the original value of the CO2 generated by biodegradation of the cruded oil.The dissimilarity in the organochemical characteristics of the Kidod shales, which cap the gas reservoirs and the oils found in the region, as well as the low degree of maturation of the Kidod, shales, negate the accepted hypothesis that these shales are the source rock of the heavy oils and the gas found in the Zohar area. The vitrinite reflectance of the reservoir rocks and of the underlying Jurassic sequences, which is only 0.5%, infers that the gas is not trapped near its site of generation.
DARWIN'S NAVIDAD EMBAYMENT, SANTIAGO REGION, CHILE, AS A MODEL OF THE SOUTHEASTERN PACIFIC SHELF
Authors: Cecioni Giovanni 
Published: December 2007

The sedimentary sequence of Darwin's Navidad embayment overlies a Carboniferous metamorphic basement, and was deposited in a NNW‐striking basin, open toward the sea. The sediments formed in a temperate climate and consist of three marine sequences—Cretaceous, Eocene, and Miocene‐Pliocene. They exihibit some potential for oil and gas. The uppermost sediments of the Navidad Group were deposited in a more extensive sea, which was deeper, with lower wave energy. Near the present Pacific coastline, the sediments are tectonically disturbed. Farther east‐and northward, the sediments are not affected by great disturbances. Some good types of stratigraphical traps, such as eolian sand beaches, may be expected.Key Idea:The model adopted here is considered as one potential basin model for petroleum exploration in the southeastern Pacific shelf, where six or more NNW‐striking open embayments are present.
TECTONIC CONTROL AND PETROLEUM GEOLOGY OF THE PALEOZOIC CLASTICS OF THE MARANHÃTO BASIN, BRAZIL
Authors: Carozzi Albert V. 
Published: December 2007

Selected paleoenvironmental maps of the Maranhão Basin from Silurian to Eo‐Carboniferous are analyzed in tercs of their source rock and reservoir potentials. These maps combine petrographic data with the distribution of clay mineral assemblages, palynofacies, trace‐metals, organic carbon and boron. Two depositional models are recognized. The first one, which lasted from Silurian to Eo‐Carboniferous, is model of coalescent deltas in which delta systems (with seven subenvironments) are separated by interdeltaic aras (with five subenvironments). The second model, limited to the Late Devonian, shows a continental ice sheet interfering with a system of coalescent deltas and generating mixed glacio‐deltaic sediments.The evolution of clastic supplies from Silurian to Eo‐Carboniferous consists of three major episodes of delta progradation strongly influenced by a synsedimentary tectonic control through lineaments of the Precambrian basement. This control concentrated the potential reservoirs in the SE portion of the basin. However, among the three major sandstone systems, the first two (Jaicos and Itaim Formations), which are the coarsest, had their reservoir properties strongly decreased by diagenetic cementation. This leaves the third one (Cabeças Formation) as the best potential target for exploration, particularly since its sandstones under lower deltaic distributaries to delta front facies interfinger with the shales of the Pimenteiras Formation, which at that level display their best developmetn as source‐beds. Further enhancement of these reservoirs is provided where their progradation extends sufficiently westward to be involved in structures along that side of the basin.
PETROLOGY, PROVENANCE, AND DEPOSITIONAL ENVIRONMENTS OF THE RESERVOIR SANDSTONES OF OSSU‐IZOMBE OILFIELD, IMO STATE, NIGERIA
Authors: Adedokun Oluwatele Alabi 
Published: December 2007

Upper Eocene immature subarkoses derived from Cretaceous sedimentary rocks, older granites and metamorphic rocks, form the reservoir sandstones of the Ossu‐Izombe oilfield, Imo State, Nigeria. These sandstones accumulated as part of a deltaic deposit. The vertical section of deltaic facies consists, from base to top, of a progradational sequence (prodelta and delta front), an aggradational unit (delta plain, marsh and interdistributary bay), and an overlying transgressive shallow marine interval. This sequence was penetrated by nearly all of the 15 wells drilled in the area. Reservoir sandstones are present within the distributary mouth bars, point bars, braided stream deposits, and the shallow marine interval.Thin section studies, electric‐log analyses, and data from modern deltas have aided in establishing the environments of deposition of these sandstone bodies. The principal results of this study are: (1) the basal C sandstone represents distributary mouth bar sands deposited at water depths of about 10 m; (2) the intermediate B group consist of point bar and distributary channel sandstone deposits of the lower delta plain; (3) the A‐2 sandstone tops the deltaic cycle as a product of braided streams; and (4) a shallow marine deposit, the A‐1.1 and A‐1 sandstones, occurs at the top of the deltaic cycle.
THE JURASSIC‐CRETACEOUS BOUNDARY IN THE SUBSURFACE OF EASTERN MEXICO
Authors: Chapa A. Cantú 
Published: December 2007

The continuous appearance of certain ammonite genera in the cores of some wells were helpful in identifying the Jurassic‐Cretaceous boundary in the subsurface of eastern Mexico. These genera belong to the families Haploceratidae, Berriasellidae, and Protancyloceratinae. The studied wells are located in a large region of the eastern Gulf Coastal Plain of Mexico, the length of which is roughly 1,500 km.Radioactivity well logging made it possible to locate the exact stratigraphic position of the ammonites in the different wells studied. As a result, it was possible to do both local and regional correlations of the upper beds of the Jurassic.As a result of the present study, the biostratigraphic subdivision of the upper Tithonian of Mexico can be given as follows:—a zone of Salinites and Parodontoceras at the top; and—a zone of Suarites at the base.
SEDIMENTOLOGICAL EVOLUTION AND SEDIMENTOLOGICAL EVOLUTION AND NATURAL RADIOACTIVITY OF TERTIARY SEDIMENTS FROM THE CENTRAL NORTH SEA
Authors: Berstad S. , Dypvik H. 
Published: December 2007

In the North Sea well studied in this paper, the radioactive isotopes of U, Th and K are shown to control the variations in the gamma‐log response. Th and K are associated with the clay fraction, while U is enriched in the silt fraction.In the volcaniclastic Palaeocene and Eocene beds, low gamma activity is due to a high content of volcanic debris poor in U and Th, while higher gamma activity in the younger beds indicates the decrease in volcaniclastic material.
GAS EVOLUTION AND CHANGE OF OIL COMPOSITION DURING STEAM FLOODING OF OIL RESERVOIRS
Authors: Akstinat M. H. 
Published: December 2007

The injection of steam into oil reservoirs is a technique commonly used for improving the production of heavy crude oils. Very often, a change in the composition of the oil and gas produced may be observed during steam flooding. In general, corrosive gases, such as H2S and CO2, are produced in increased quantities.In laboratory experiments on sulphur‐bearing reservoir minerals and crude oils the origin of the change in oil and gas composition was investigated. Temperatures up to 370°C were applied to study temperature‐ and rate‐dependent phenomena. By means of X‐ray fluorescence, gas chromatography and chemical precipitation methods, the change in the sulphur material balance was studied.It was shown that gas evolution depends strongly on the temperature of the steam injected. Furthermore, it was possible to prove that the gases evolved during steam flooding (such as CO2, H2S etc.) originate from the decomposition of crude oil components. Besides these investigations, a drastic viscosity increase of the residual crude oil was observed after steam injection was applied.It is concluded that the production of H2S and CO2 may be controlled by temperature adjustment of the steam being injected.
SUBSIDENCE, SEDIMENTATION AND PETROLEUM SYSTEMS
Authors: Perrodon A. , Masse P. 
Published: December 2007

Analysis of a number of petroleum provinces has emphasised the importance of sedimentary factors as well as subsidence processes. Subsidence appears to depend on a small number of mechanisms ‐ tectonics, heat flow and gravity. Taking into account thegeodynamic context in which these processes develop, it is possible to compile a classification of subsidence types which is distinct from the usual classifications in terms of basins. The type of subsidence influences the deposition rate, which determines both the potential and the habitat of petroleum. Moreover, existing statistics sho w that the number of “giant”fielako, r thep otential of a petroleum province largely depend on the types of subsidence and subsequent tectonic processes.However, it is also important to consider the history of a basin in terms of flows: geothermal flows from the mantle and crust; and water and hydrocarbon flows through the sedimentary volume. For these flow transfers, climatic and sedimentary factors, as well as variations in sea level, play a role which is as important as subsidence and uplift in controlling the distribution of non‐deposition areas, unconformities, seals and reservoirs. For example, periods of generalized transgression are favorable to both the development of carbonate platforms, and the formation of impervious horizons, seals and source rocks capable of sealing pre‐existing rifts.Therefore, a petroleum province can be considered as the final result of an organized set of geological events (in space and in time) that can be called apetroleum system. In such a system, thesequence ofsubsidencemovements and associatedflows isjust asdecisiveas lithological and geometric factors in the formation of a group of pools. This concept of the succession of geodynamics and sedimentary processes which affect petroleum potential is developed, and specific examples of petroleum systems from the North Sea, the Arabian Platform and the Congo Basin are presented.
THE EVOLUTION OF THE SOUTHERN PASSIVE MARGIN OF THE HIMALAYAN TETHYS: MODEL IMPLICATIONS AND CONSTRAINTS ‐ I
Authors: Bhat Mohd. Ismail 
Published: December 2007

To outline lthe process of formation of the Tethys Ocean and its developemt from teh Late Carboniferous (Hercynian) epeirogenic phase until teh end of the Cretaceous, (when this ocean started vanishing), an earlier proposed model, involving lithospheric uplift, stretching and developmetn f anastomosing normal faults, which was suggested to explain the thermotectonic evolution of the lKashmir basin, is extended to cover the region from Kashmir to Kempa Dzong (NE Silkkim).Basement subsidence curves show an overall exponential trend in agreement with teh common behaviour of passive margins. The anomalour Late Jurassic ‐ early Creataceous uplift of the marigin is difficult to explain wiht the available data; however, it seems likely to be related to the very restricted ocean‐floor spreading phase in early Late Creataceous time. The well preserved continental margin suggests a width of <500 km for the Tethys Ocean.The model and the inferred limited width of the Tethys Ocean have several implications for the evolution of the himalayas. For example: (1) the Main Central Thrust and Main Boundary Thrust are reactivated normal listric faults, which reversed their direction fo move, emt during the closing phase of the Tenthys Ocean; (2) the gravity high along the entire Higher Himalayas is due to the presence of transitional‐zone basic material, intruded during the rift phase; and (3) the limited width fo the Tethys Ocena does not support alleged large‐scale subduction along this belt.Finally, a few date (known and model‐derived) and conceptual constraints are pointed out. These must be considered in the evolultion of the Himalayas in general, and before in voing subduction in the Himalayas in particular. They include: the time required for passive margins to change to fracture boundaries; the north ward movement of India indicated by paleomagnetic data; th sinistral movement between norhtern and soutehrn continents; the p0osition of the Ladakh batholity within the Indus‐Tsansgpo Suture Zone; the 235+‐13Ma†age of a section fo this batholith; the occurrence of radiolarian chert within underformed beds; the suggested involvement of the Earth's rotational forces in plate‐tectonic driving mechanisms; and the possibility of many changes in teh spin velopcity of the Earth during the lifetime of Tethys.
MIGRATION IN FRACTURE NETWORKS; AN ALTERNATIVE INTERPRETATION OF THE SUPPLY OF THE “GIANT” TAR ACCUMULATIONS IN ALBERTA, CANADA ‐ I†
Authors: du Rouchet J. 
Published: December 2007

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 sub‐crops.
ORIENTING CONVENTIONAL CORES FOR GEOLOGICAL PURPOSES: A REVIEW OF METHODS
Authors: Davison I. , Haszeldine R. S. 
Published: December 2007

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:

Cutting oriented. cores;
Using dipmeters;
Re‐orienting in highly deviated holes;
Using remanent palaeomagnetism.

The accuracy, costs and limitations of the methods are considered.
IN SITU FORMATION OF PETROLEUM IN OOLITES‐ II: A CASE STUDY OF THE ARAB FORMATION OOLITE RESERVOIRS
Authors: Ibe A. C. 
Published: December 2007

In Part I, (Journ. Petrol. Geol. 7 (3) 267–276) a scheme for the in situ generation and accumulation of hydrocarbons was presented. It was concluded that the indigenous origin of petroleum in oolites, which preculdes a long and wasteful primary migration process, affords another explanation for the exceptionally rich petroleum accumulations which characterise oolite reservoirs. The present paper now tests the validity of that proposal by a selected case study.For an unequivocal discussion of an oolite reservoir productive of petroleum generated in situ, it would be necessary to describe in some detail those formations either underlying, overlying or lateral to the formation of interest which, because of their hydrocarbon content in the general region, might perhaps be supposed to have been the original source of the petroleum now found in the oolites. such an account would be more detailed than space permits. The need arises, therefore, for the selection of an example which allows the least number of alternative possibilities. This was the guiding principle behind the choice of the prolific Arab Formation (Upper Jurassic) of Saudi Arabia as a case study (Fig. 1)
THE PRE‐ZAGROS INTEGRITY OF THE IRANIAN PLATFORM
Authors: Kashfi Mansour S. 
Published: December 2007

The Hormoz Formation of InfraCambrian age is the oldest unit recognized in southern Iran. It consists mainly of salt, other evaporites and débris of basement rocks. Some huge blocks of the uppermost PreCambrian and Lower Cambrian layered rocks were lifted to the surface by uprising Hormoz salt.A detailed field investigation within three major salt diapirs located in the SE segment of the Zagros Fold Belt was carried out. Some lithologic‐stratigraphic correlations between three formations within selected salt domes on the western part of the Zagros crush zone, and the equivalent units on the eastern part, are established.The Permian transgressive sea deposited basinal clastics unconformably on the Devonian in central Iran, and overstepped the basement rocks in central Arabia. The Pecten species of the Lower Jurassic Neyriz Formation of the Zagros Fold Belt can be correlated with the Nayband Formation of central Iran. The Tertiary evaporites of SSW Iran are correlated with the Tertiary evaporites of central Iran.Evidence discussed indicates the presence of a single tectonic entity with no geologic break between SW Iran and the plateau of Iran in the NE.