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931.
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. 相似文献
932.
Natural Hazards - Individual household emergency planning is the most fundamental and can be the least expensive way to prepare for natural disasters. However, despite government and nonprofit... 相似文献
933.
M. A. Solovyeva A. V. Starovoytov G. G. Akhmanov O. M. Khlystov A. V. Khabuev M. Yu. Tokarev D. A. Chensky 《Moscow University Geology Bulletin》2016,71(6):416-428
As a result of careful interpretation of the data of recent seismo-acoustic surveys, two major seismic complexes were identified in the structure of the upper sedimentary section of the north-western slope of Kukuy Griva (ridge). They are composed of several inner seismo-facies, which are very characteristic and separated with well-expressed regional reflector. Seismic and acoustic data revealed evidences of numerous landslide processes which were different in age and peculiarities of manifestation. For the first time, detailed schemes of seismo-facies distribution are compiled for major seismic complexes at the area. The boundary between seismic complexes is dated as 150 thousands years. It is shown that sliding was more intensive during Late Pleistocene and Holocene, reflecting activation of tectonic movements in this part of Baikal rift system. 相似文献
934.
V. A. Nikishin N. A. Malyshev A. M. Nikishin D. Yu. Golovanov V. F. Proskurnin A. V. Soloviev R. F. Kulemin E. S. Morgunova G. V. Ulyanov P. A. Fokin 《Doklady Earth Sciences》2017,473(2):402-405
New data on the ages of detrital zircons from folded basement rocks and cover sediments of the Severnaya Zemlya archipelago and Izvestiy TSIK islands have been obtained. The basement age is defined as Cambrian (pre-Ordovician). The Ordovician and Silurian sandstones were mainly formed by erosion of the basement rocks. The Devonian sandstones were formed by debris sourced from the Caledonian orogen. The Carboniferous–Early Permian molasse was formed simultaneously with the erosion of the Carboniferous granitoids and weathering of the Ordovician volcanic arc rocks and the Cambrian basement. The North Kara basin was formed in the Ordovician as a back-arc basin. It experienced its main compression deformations at the boundary of the Devonian and Carboniferous and in the Carboniferous. 相似文献
935.
Duncan Keppie J. Gregory Shellnutt J. Dostal Jaroslav Fraser Keppie D. 《International Journal of Earth Sciences》2018,107(3):955-969
International Journal of Earth Sciences - The Ediacaran–Ordovician Meguma Supergroup was thrust over Avalonia basement prior to the intrusion of post-Acadian, ca. 370 Ma, S-type... 相似文献
936.
Fluorometric Determination of Chlorophyll 总被引:32,自引:0,他引:32
937.
D. K. Wagh 《Pure and Applied Geophysics》1970,82(1):62-65
Summary Cauchy theory of initial stress has been applied to investigate the influence of uniform initial stress on the propagation of plane waves in an unbounded elastic medium. It is found that if the initial principal stresses are unequal, the velocity depends on the direction in which the wave propagates, whereas when the initial principal stresses are equal, the velocity is independent of the direction of wave propagation. 相似文献
938.
In the Chindwin Basin in northern Burma, there is a system of five Pleistocene terraces in which gold placers with low concentrations of platinum-group minerals (PGM) occur. Samples were taken from four sites in the Chindwin Basin and one from near an ophiolite occurrence on the northeast side of the Chindwin Basin; they were studied under the microscope, with a scanning electron microscope, and an electron microprobe. The main minerals were Pt-Fe and Os-Ir-Ru alloys, usually in a ratio between 2 and 5. In most cases, the shape of the grains allowed a quick distinction between the two types. Sperrylite, laurite, irarsite, cooperite, tulameenite, and isomertieite occur infrequently as individual mineral grains and sometimes as inclusions in the alloy grains. Braggite, platarsite, hollingworthite, bowieite, keithconnite, cuproiridsite, malanite, stibiopalladinite, geversite, kashinite, several unnamed PGM, and Fe, Ni, and Cu sulfides were observed as inclusions, mainly in the Pt-Fe alloys and also to a lesser extent in the Os-Ir-Ru alloys. Lamellar and myrmekite-like intergrowths, oriented exsolution lamellae, and idiomorphic inclusions of sulfides in the alloys indicate a magmatic origin of the PGM. The origin of the PGM is assumed to be ophiolites in northern Burma. A continual decrease in mean grain size occurred during transport.
With 8 Figures 相似文献
Platingruppenminerale in quartären Goldseifen im oberen Chindwingebiet in Nord-Burma
Zusammenfassung Im Gebiet des Chindwin Basin in Nordburma ist ein System von fünf pleistozänen Terrassen ausgebildet, in denen Goldseifen mit geringen Anteilen an PGM auftreten.PGM-Konzentrate von vier Vorkommen des Chindwin Basin und eine weitere Probe aus der Nähe eines Ophiolithvorkommens im Nordosten des Chindwin Basin wurden mit optischer Mikroskopie, Rasterelektronenmikroskopie und Mikrosonde untersucht.Hauptmineralien sind Pt-Fe-Legierungen und Os-Ir-Ru-Legierungen in einem Verhältnis von 2: 1 bis 5: 1. Ihre Morphologie kugeliger oder plattiger, teilweise idiomorpher Körner erlaubt in den meisten Fällen eine rasche Identifizierung der beiden Typen. Sehr selten treten als Einzelminerale, aber auch als Einschlüsse in Legierungen, Sperrylith, Laurit, Irarsit, Cooperit, Tulameenit und Isomertieit auf. Braggit, Platarsit, Hollingworthit, Bowieit, Keithconnit, Cuproiridsit, Malanit, Stibiopalladinit, Geversit, Kaschinit, einige unbekannte PGM und Fe-, Ni- und Cu-Sulfide wurden nr als Einschlüsse, hauptsächlich in Pt-Fe-Legierungen, weniger in Os-Ir-Ru-Legierungen, beobachtet.Lamellare und myrmekitische Verwachsungen, orientierte Entmischungen und idiomorphe Einschlüsse von Sulfiden in Legierungen weisen auf eine magmatische Entstehung der PGM hin. Die Herkunft der PGM wird in Ophiolithen Nordburmas vermutet. Beim Transport hat eine kontinuierliche Abnahme der mittleren Korngrösse stattgefunden.
With 8 Figures 相似文献
939.
AbstractDuring the past 50 years, many geological and ore-deposit investigations have led to the discovery of the Fe–P–(Ti)-oxide deposits associated with mafic–ultramafic–carbonatite complexes in the Kuluketage block, northeastern Tarim Craton. In this paper, we discuss the genetic and ore-forming ages, tectonic setting, and the genesis of these deposits (Kawuliuke, Qieganbulake and Duosike). LA-ICP-MS zircon U–Pb dating yielded a weighted mean 206Pb/238U ages of 811?±?5?Ma, 811?±?4?Ma, and 840?±?5?Ma for Kawuliuke ore-bearing pyroxenite, Qieganbulake gabbro and Duosike ore-bearing pyroxenite, respectively. The CL images of the Kawuliuke apatite grains show core–rim structure, suggesting multi-phase crystallisation, whereas the apatite grains from Qieganbulake and Dusike deposits do not show any core–rim texture, suggesting a single-stage crystallisation. LA-ICP-MS apatite 207Pb-corrected U–Pb dating provided weighted mean 206Pb/238U ages of 814?±?21?Ma and 771?±?8?Ma for the Kawuliuke ores, and 810?±?7?Ma and 841?±?7?Ma for Qieganbulake and Duosike ores, respectively. The core–rim texture in apatite by CL imaging as well as two different ore-forming ages in the core and rim of the apatite indicate two metallogenic events for the Kawuliuke deposit. The first metallogenic period was magmatic in origin, and the second period was hydrothermal in origin. The initial ore-forming age of the Kawuliuke Fe–P–Ti mineralisation was ca 814?Ma and the second one was ca 771?Ma. On the other hand, the ore-forming ages of the Qieganbulake and Duosike deposits were ca 810?Ma and ca 841?Ma, respectively. Qieganbulake and Duosike deposits were of magmatic origin. Combined with previous geochronological data and the research on the tectonic background, we infer that the Kawuliuke, Qieganbulake and Duosike Fe–P–(Ti)-oxide deposits were formed in a subduction-related tectonic setting and were the product of subduction-related magmatism. 相似文献
940.
V. J. Loveson A. R. Gujar S. D. Iyer P. Srivastava G. M. Tirodkar R. A. A. Luis 《Environmental Earth Sciences》2014,72(10):4155-4166
The ground-penetrating radar (GPR) was used to trace the subsurface details in the Palshet coastal zone (Maharashtra) as it exhibits an interesting array of geomorphological features. Furthermore, our main goal was to identify and locate features that might have formed during a reported extreme event and its effects on the flow of the nearby Sundri River. Two profiles (8 and 4 m depth) were collected across the beach and along the backshore, respectively. While the 8-m depth profile (west to east; across the beach) indicates a series of coastline regression in this area, the 4-m depth profile along the coastline (north to south) in the backshore zone reveals two significant incidents viz., (1) stages of development of the paleo-channels that indicate the migration of the Sundri River towards south and (2) huge sediment deposits up to 2.5-m thick in the backshore area. The erosional relict surface (~2.5 m depth) was traced along with various spells of sediments that perhaps occurred due to an extreme event. Sand samples were collected from two trial pits along the GPR profiles to understand the sedimentology and mineralogy in the backshore area. These data together with beach profiles and geomorphological maps suggest that the sands were deposited by an extreme event perhaps during the 1854 cyclonic storm. The sands were trapped in suitable geomorphological sites along the Palshet coast and these sand deposits of about 2.5 m thickness forced the River Sundri to shift its course towards the south. This new revelation facilitates a further study that could focus on the nearby coastal areas to document such extreme event deposits and their influence on the geomorphic set-up. 相似文献