Evolution of sedimentary basins from the standpoint of petroleum origin and accumulation—an approach for a quantitative basin study

Generation, migration and accumulation of petroleum in a sedimentary basin is a function of geologic, hydrodynamic and thermodynamic development of the basin and the type and amount of organic matter. Temperature history not only determines rate of hydrocarbon generation, but also affects paleohydrodynamics and physical and thermal properties vs depth relationships. Therefore, paleotemperature is the most important parameter. Paleohydrodynamics together with geologic history of the basin is important in shaping secondary migration patterns and accumulation of hydrocarbons.Quantification of all the above processes is complicated. Steps in constructing a deterministic dynamic model for calculation of petroleum potential during a sedimentary basin development are stated and analyzed in this paper. The effect of paleotemperature variations on petroleum generation and on physical properties of sedimentary sequences are illustrated by numerical examples. Computer models will enable exploration geologists to make quantitative exploration predictions in sedimentary basins.     

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Ohne Zusammenfassung Technische Hochschule Karlsruhe     

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山东济南下寒武统朱砂洞组软沉积变形中燧石的Sm-Nd年龄测定及其意义

在济南南部下寒武统朱砂洞组丁家庄段硅质白云岩中,发育地震引起的硅质触变脉、硅质触变沉陷构造和触变楔等软沉积变形构造。从同一地震触变沉陷构造中,采得一组灰黑色燧石样品。使用英国VG354同位素质谱仪和同位素质谱分析方法,测得每个样品的 ¹⁴⁷Sm/¹⁴⁴Nd 和 ¹⁴³Nd/¹⁴⁴Nd 同位素值。采用Sm-Nd 等时线法,对燧石进行了测年。获得燧石的成岩年龄为530.8±6.1 Ma,由于软燧石(硅胶体)成岩至少经历了0.1 Ma的时间,所以,地震沉积事件发生在530.7±6.1 Ma,属早寒武世早期。由于测年结果与沧浪铺阶的下界年龄接近,山东朱砂洞组丁家庄段无化石且河南省标准地层剖面中的整个朱砂洞组属沧浪铺阶,这暗示济南地区朱砂洞组丁家庄段属沧浪铺阶。本次测年得到了鲁西地区第1个下寒武统的同位素年龄值,这对确定该地区早寒武世地震沉积事件发生的时间具有参考价值和意义,也为深入研究鲁西地区寒武纪地层提供了新资料。     

Hydrothermale Lösungen

Zusammenfassung Das hydrothermale Auflösungsverhalten der vorwiegend als Gangarten auf-tretenden Mineralphasen Fluorit (CaF₂), Baryt (BaSO₄), Cölestin (SrSO₄) und Anglesit (PbSO₄) läßt sich übersichtlich in einem Temperatur-Löslichkeitsdiagramm darstellen und mit dem bekannten, qualitativ ähnlichen System SiO₂-H₂O vergleichen.Gegenüber dem molekulardispers gelösten SiO₂ ergeben sich aber für die in Ionen dissoziierten Lösungen der schwerlöslichen Sulfate und des Fluorits beträchtliche Verschiebungen der Sättigungsgleichgewichte, insbesondere bei Anwesenheit von Elektrolyten als Lösungsgenossen.Diese Beeinflussung, die für die genetischen Verhältnisse der Minerallagerstätten von entscheidender Bedeutung ist, wird für 0,1–2,0 normale NaCl-Lösungen im NaCl-Konzentrations-Löslichkeits-Diagramm der Minerale Fluorit, Baryt, Cölestin und Anglesit isotherm bis zum Siedepunkt der wäßrigen Mischphasen untersucht.Ferner wird das Löslichkeitsverhalten in den ternären Systemen BaSO₄-NaCl-H₂O und SrSO₄-NaCl-H₂O für Baryt und Cölestin gegen 2,0n NaCl-Lösungen entlang der Grenzkurve des Dreiphasengebietes und für die Isochoren 0,326 bis 0,6 bis 600° C und 2000 Bar dargestellt und mit den entsprechenden Verhältnissen der reinen wäßrigen Systeme verglichen.Ein abweichendes inkongruentes Auflösungsverhalten von Alumosilikaten mit Schichtgitterstruktur läßt sich am Beispiel des Muskovits durch die experimentelle Bestimmung der nichtstöchiometrischen Molekularverhältnisse SiO₂/K₂O und SiO₂/Al₂O₃ in den gesättigten Lösungen für den hydrothermalen Existenzbereich des Muskovits nachweisen.

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The behaviour of solubility for some minerals, which were for the most part found as vein minerals, was determined experimentally and is represented by summarizing diagrams.In the temperature-solubility diagram the hydrothermal solubility of fluorite, barite, celestine and anglesite is compared to the solubility of quartz and muskovite for the boundary curve of the three-phase region and for some isochores. As opposed to SiO₂, which is molecularly dispersed in solution, the ionic solutions of the systems CaF₂-H₂O, BaSO₄-H₂O, SrSO₄-H₂O and PbSO₄-H₂O show considerable displacement of the saturation equilibrium when other components are present in the solution.This influence on the solubility, significant for the genetic relations of mineral deposits, was quantitatively analyzed for 0.1–0.2 n-NaCl solutions. The results are isothermally shown in the NaCl-concentration solubility diagram within the boundaries of room temperature and the boiling point of the aqueous mixed phases.In the tenary systems BaSO₄-NaCl-H₂O and SrSO₄-NaCl-H₂O, the hydro-thermal solubility of barite and celestine in 2.0 n-NaCl solutions is also shown for the range of the boundary curve of the three-phase region and for the isochores 0.326–0.6 up to a temperature of 600° C and a pressure of 2000 bar. These solubilities are then compared with the diagrams of solubility for pure aqueous solutions.The irregular and incongruent behaviour of the solubility of aluminium-silicates of a layered-lattic structure is demonstrated for the system KAl₂(OH)₂-AlSi₂O₁₀-H₂O in the presence of muscovite by experimental determination of the non-stoechiometric molecular proportions of SiO₂K₂O and SiO₂ Al₂O₃. Such determination was conducted in saturated solutions for the hydrothermal range of the existence of muscovite.The geological importance of the knowledge of hydrothermal data of solubility and their application to the process of the hydrothermalmagmatic series and hydrothermalmetamorphosis is discussed.

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Résumé Le comportement de dissolution expérimentalement déterminé de certains minéraux trouvés surtout en filons est exposé en le résumant par diagrammes.La solubilité hydrothermique de fluorine, barytine, célestine et anglésite est comparée pour la courbe limitante (de la région triphasée) et pour les isochores 0,326–0,6 g.cm³ du diagramme température-solubilité avec le comportement de dissolution du quartz et de la muscovite. Les solutions ioniques des systèmes CaF₂H₂O, BaSO₄-H₂O, SrSO₄-H₂O et PbSO₄-H₂O montrent, comparées au SiO₂ dissous en dispersion moléculaire, de différences importantes d'équilibres de saturation en présence d'associés de solution.Cette influence sur la solubilité qui est d'une importance décisive pour les conditions génétiques des gisements de minéraux, a été examinée quantitativement pour les solutions 0,1–0,2—normales de NaCl. La présentation s'est faite isothermiquement dans le diagramme de concentration-solubilité de NaCl entre la température de chambre et le point d'ébullition des phases mixtes aqueuses.Dans les systèmes ternaires BaSO-NaCl-H₂O et SrSO₄-NaCl-H₂O la solubilité hydrothermique de barytine et de célestine en des solutions 2,0-normales de NaCl est présentée également pour l'espace des courbes limitantes de la région triphase et pour les isochores 0,326–0,6 jusqu'à 600° C et 2000 Bar. Elle est comparée avec les courbes de solubilité de systèmes purement aqueux. Le comportement de dissolution divergeant incongruent des silicates d'alumine à structure stratifiée en treillis est démontré pour le systême KAl₂(OH)₂-AlSi₃O₁₀-H₂O par exemple de la muscovite en déterminant expérimentalement les proportions moléculaires non-stochiométriques SiO₂ K₂O et SiO₂Al₂O₃ dans les solutions saturées pour la domaine d'existence hydrothermique de la muscovite.Importance géologique de la connaissance des dates de solubilité hydrothermique et leur application sur les événements des conséquences hydrothermiques-magmatiques et sur les événements de la métamorphose hydrothermique sont discutées.

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y 600° 2000 . (CaF₂), ( SO₄), . (SrSO₄) (PbSO₄) - Sio₂-₂.

     

Comments on the Gravity and Magnetic Anomalies of Saros Bay using Wavelet Approach

In this paper, residual and regional gravity and magnetic anomalies of Saros Bay are separated using wavelet method. Wavelet is one of the modern, stochastic image approaches processing technique in electronics. The vertical, horizontal and diagonal components of wavelet output are evaluated simultaneously and an underground model is obtained by suitable cross-sections. Thus the geological and tectonic properties of Saros Bay are extracted. Our proposed model is confirmed by deep and shallow seismic researches of Turkish Petroleum Cooperation (TPAO). The South-East region of Saros Graben is formed by strike slip Ganos Fault and Anafartalar reverse Fault that lies on the east of Ganos Fault. On the Northwest region, there is strike slip component fault resulting in the Enez Graben. Here we detected two new oval type geological structure, both of them starting from the Eastern direction of Canakkale Dardanelles and but one of them continuing through Gelibolu Peninsuls, while the other tending to the Enez Graben. We think that these structures are the ruins of a very old sea in this region. This revised version was published online in November 2006 with corrections to the Cover Date.     

Sex-specific biochemical and histological differences in gonads of sea urchins (Psammechinus miliaris) and their response to phenanthrene exposure

Female and male individuals of the same species often differ with respect to their susceptibility to toxicant stress. In the present study, sea urchins (Psammechinus miliaris) of both sexes were exposed to high (150 μg L?1) and environmentally relevant (5 μg L?1) concentrations of phenanthrene over 10 days. While food intake was significantly decreased following exposure to 150 μg L?1 phenanthrene, histological indices (lipofuscin accumulation, fibrosis, oocyte atresia), energetic status (energy charge, sum adenylates, AMP/ATP ratio) as well as ascorbate levels in the gonads showed either little or no effect upon phenanthrene exposure. However, most parameters (vitamin C, energy charge, sum adenylates, AMP/ATP ratio, ATP and ADP concentrations, lipofuscin content, fibrosis) significantly differed between male and female animals. This study illustrates the difficulties to identify toxic injury in reproductive tissue as it may be superimposed by gametogenesis and spawning of gametes.     

Morphometric and molecular data on two mitochondrial genes of a newly discovered chimaeran fish (Hydrolagus melanophasma, Chondrichthyes)

Fresh and preserved (type material) specimens of the black ghost chimaera Hydrolagus melanophasma were compared for morphometric characteristics. A molecular comparison was also performed on two mitochondrial gene sequences (12S rRNA and 16S rRNA gene sequences). While significant differences in measurements were found, the differences were not attributable to sexual dimorphism or the quality of the specimens, but to the sample size and the type of statistical tests. The result of the genetic characterization showed that 12S rRNA and 16S rRNA genes represented robust molecular markers that characterized the species.     

Late Quaternary Seismic Stratigraphy of the Eastern Bengal Shelf

An ultra-high-resolution seismic study of the eastern Bengal Shelf with the parametric narrow-beam echosounder Parasound allows the interpretation of late Quaternary depositional patterns in terms of seismic stratigraphy. Accommodation space was still present on the outer shelf during the last lowstand, where a prograding delta developed in the western survey area. Oolitic beach ridges were later formed on top of this lowstand delta. Farther east, large parts of the shelf were exposed to subaerial erosion and a river system extended seaward across the area. A subaqueous highstand delta prograded southwards following the maximum transgression about 7,000 years ago. Its foreset beds exhibit acoustic voids very likely generated by sediment liquefaction, possibly caused by episodic energetic events such as major cyclones and/or earthquakes. Bottomset sediments extend seaward close to the shelf break in the west, whereas no Holocene sediments cover the outer shelf in the east.     

High-resolution sediment echosounding off Peru: Late Quaternary depositional sequences and sedimentary structures of a current-dominated shelf

About 6000 km of both bathymetric and high-resolution acoustic profiles were acquired on the shelf and upper slope offshore Peru between 9° S and 14° S. Two new sediment echosounder systems – SEL-96 and SES-2000DS – provided details of the sedimentary structures of the Quaternary sequences within the Sechura-Salaverry, Huacho and Pisco Basins. To a great extent, the poleward undercurrent determines the distribution of sediments. The undercurrent has generated numerous erosional unconformities, it has winnowed hardgrounds and has created mudwaves common between 250 m and 400 m water depth. Distinct subbottom reflectors within sedimentary units represent hiatuses due to periods of intensified winnowing or non-deposition. Erosional unconformities usually marked by pronounced reflectors suggest shifts of the undercurrent system related to climatic changes and eustatic variations of sea level. On a larger scale, the stacked prograding depositional sequences reflect the sea-level cycles of the Middle Pleistocene to the Holocene. Based on the stratigraphy of our piston cores and that of Ocean Drilling Program (ODP) Site 680, the depositional sequences limited by extended unconformities were assigned to oxygen isotope stages 1 to 7. Other sedimentary structures are small straight channels that were conduits for downslope sediment transport. Deformed sediments associated with synsedimentary normal faults result from creep movements indicating beginning slope failure.