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Kumar M. Dinesh Tandon Shubham Bassi Nitin Mohanty Pradipta Kumar Kumar Saurabh Mohandas Manish 《Natural Hazards》2022,110(3):2035-2057
Natural Hazards - Many coastal cities in developing countries are at the risk of flooding due to a progressive increase in the built-up areas and poor management of storm water. The flooding... 相似文献
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G. N. Zastenker E. Salerno F. Buehler P. Bochsler M. Bassi Yu. N. Agafonov N. A. Eismont V. V. Khrapchenkov H. Busemann 《Astrophysics》2002,45(2):131-142
One of the important problems in astrophysics is the determination of the abundances of the helium isotopes 3He and 4He in various regions of the universe, since those abundances can provide evidence of the intensities of various possible processes of the production and decay of light elements and can thereby reflect their history. In this paper we describe the procedure and results of the first determination by a direct method of the abundances of helium isotopes in the local interstellar medium surrounding the solar system. The experiment was carried out on the piloted MIR station by the prolonged exposure in open space of specimens of metallic foil with their subsequent return to earth and detailed laboratory mass-spectrometric analysis. As a result, we were able to obtain estimates of the 4He density (about 7.5·10-3 cm-3) and the 3He/4He isotopic ratio (about 1.7·10-4) for the local interst ellar medium. 相似文献
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Md. Aftabuzzaman Kazuki Yomogida Shota Suzuki Hideko Takayanagi Akimasa Ishigaki Shiki Machida Yoshihiro Asahara Koshi Yamamoto Naoto Hirano Shin-Ichi Sano Shun Chiyonobu Davide Bassi Yasufumi Iryu 《Island Arc》2021,30(1):e12400
Sedimentological, geochemical, and chronological analyses were carried out on 18 carbonate rock samples collected at depths of 938, 1085, and 3354 m on the western slope of Minamitorishima (Marcus Island), which is located near the western margin of the Pacific Plate. Four groups of carbonate rocks were distinguished: a mollusk-rich limestone, a coral-rich dolomite, a foraminiferal-nannofossil packstone, and a phosphatized mudstone/wackestone. The mollusk-rich limestone is characterized by the dominance of bivalves (including rudists) and gastropod shells. Strontium isotope ratios (87Sr/86Sr) and Mesorbitolina ex gr. texana (a large benthic foraminifer) indicate that the shallow-water carbonates were deposited during the late Aptian–early Albian (ca. 123–111 Ma). The coral-rich dolomite is characterized by abundant scleractinian corals and nongeniculate coralline algae associated with encrusting acervulinid foraminifers. The biotic composition is similar to that of the Oligocene–Pleistocene carbonates reported from other seamounts in the northwestern Pacific. Geochemical data show that the coral-rich carbonates were dolomitized at 9.5–6.8 Ma (Tortonian–Messinian) and that normal seawater was the most likely parent fluid. The foraminiferal-nannofossil packstone is a semi-consolidated foraminiferal-nannofossil ooze and was deposited during the Pleistocene (0.99–0.45 Ma). The phosphatized mudstone/wackestone is marked by the absence of macrofossils and the presence of traces of planktic foraminifers. Although its depositional age is not constrained, the Sr isotope ratios indicate that the phosphatization occurred at 33.2–28.9 Ma. After the deposition of the Cretaceous shallow-water carbonates, including the mollusk-rich limestone, Minamitorishima was drowned and its top was covered with a pelagic cap, represented by the mudstone/wackestone. The late Eocene–early Oligocene volcanism (40.2–33.2 Ma) caused episodic uplift and returned the top of Minamitorishima to a shallow-water environment. After the early Oligocene phosphatization of the pelagic cap, coral reefs flourished on the top of this island. The reef limestone was dolomitized during the Tortonian–Messinian. 相似文献
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Sara Emanuel Tokiyuki Sato Shun Chiyonobu J. Bruce H. Shyu Davide Bassi Yasufumi Iryu 《Island Arc》2021,30(1):e12411
We established a high-resolution calcareous nannofossil biostratigraphy for the late Pliocene–Pleistocene by analyzing a 242 m-thick, continuous sedimentary succession from Ocean Drilling Program Site 1146, Hole A, in the South China Sea (SCS). A total of 14 calcareous nannofossil datums were detected in the SCS succession. They are, in descending order: first occurrence (FO) of Emiliania huxleyi, last occurrence (LO) of Pseudoemiliania lacunosa, LO of Reticulofenestra asanoi, FO of Gephyrocapsa parallela, FO of R. asanoi, LO of large Gephyrocapsa spp., FO of large G. spp., FO of Gephyrocapsa oceanica, FO of Gephyrocapsa caribbeanica, LO of Calcidiscus macintyrei, LO of Discoaster brouweri, LO of Discoaster pentaradiatus, LO of Discoaster surculus, and LO of Discoaster tamalis. The FO of E. huxleyi was not precisely detected due to poor preservation and dissolution of nannofossils in the underlying strata. We refined the previous calcareous nannofossil biostratigraphy in the SCS by identifying Gephyrocapsa species and four evolutionary extinction events of the genus Discoaster. The proposed calcareous nannofossil biostratigraphy correlates with those reported in other terrestrial and marine areas/sites and global benthic foraminiferal δ18O records. The age–depth curves based on nannofossil biostratigraphy indicate a significant increase in the sedimentation rates at the LO of R. asanoi (0.91–0.85 Ma). The timing of this increase corresponds to reef expansion in the Ryukyu Islands linked to a stepwise increase in Kuroshio Current intensity. This timing is broadly coeval with a sea surface temperature increase of ∼2 °C in the northwestern Pacific due to expansion of the Western Pacific Warm Pool towards the north and south subtropical regions. This can be explained by increased weathering and erosion of terrestrial areas in glacial periods and increased rainfall causing higher sediment transport in interglacial periods, which were both linked to Middle Pleistocene Transition-related climatic changes. 相似文献
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Relative importance of strain rate and rheology for the mode of continental extension 总被引：3，自引：0，他引：3
G. Bassi 《Geophysical Journal International》1995,122(1):195-210
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F. BÜhler M.L. Bassi P. Bochsler O. Eugster E. Salerno G.N. Zastenker YU.N. Agafonov L.G. Gevorkov N.A. Eismont A.V. Prudkoglyad V.V. Khrapchenkov N.I. Shvets 《Astrophysics and Space Science》2000,274(1-2):19-24
For the first time, the method of collecting impinging atoms in pretreated foil surfaces during exposure from a spacecraft
allowed to detect in the laboratory, after retrieval of the foils,4He gas of interstellar origin in the expected concentration.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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Dr. H. G. L. Bassi 《International Journal of Earth Sciences》1988,77(2):491-511
The statistical processing of megafractures and lineaments of the Argentinean, Chilean and Uruguayan territories, and the determination of the structurogenetic orientations of more than fifty phylohydrothermal mineral deposits has led to the development of a hypothesis of the existence of two planetary fracture network systems in the South American Austral Cone.An orthogonal netting, referred to as the »Gondwana Region Network«, with a N60W-N30E trend and a 25 km basic equidistance, belonging to a major net system of 200 km on a side, is located approximately north of 39 south latitude. Another orthogonal netting, referred to as the »Patagonian Region Network«, is located south of the Gondwana Region Network. The Patagonian Region Network has a N35W-N55E, trend with an equidistance of 35 km, and is located in a major net of 140 km on a side.A statistical review of 371 ore deposits in the Gondwana Region, primarily those of copper, gold, lead and zinc, lead to the inference that the Large Ore Deposits (such as Chuquicamata, Salvador, Potrerillos, Agua de Dionosio, Famatina, Pachon-Pelambre, Disputada and Teniente) are situated near networks of 100 and 200 km on a side. Also, the 83 Outstanding Ore Deposits are clearly controlled by the key equidistance of 25 km and the Minor Ore Deposits are not dependent on the regmagenic network and are therefore randomly distributed.Fifty-four mineral deposits have been processed in the Patagonian Region to date, with four Outstanding Ore Deposits distributed with a portion of the Minor Ore Deposits in a net system of between 70 and 140 km on a side. However, the Minor Ore Deposits are more closely associated with a key alternation of 35 km.Sixty percent of the pre-Mesozoic granitiod bodies are also controlled by supraregional fracture networks which will be discussed in this paper.
Zusammenfassung Die statistische Auswertung von Gro\brüchen und Lineamenten in Argentinien, Chile und Uruguay und die Bestimmung der strukturgenetischen Orientierung von mehr als 50 hydrothermalen Minerallagerstätten hat zur Entwicklung einer Hypothese über die Existenz zweier gro\räumiger Bruchsysteme im südlichen Südamerika geführt.Ein rechtwinkliges Netz mit einem Gitterabstand von 25 km und N60W-N30E Streichen befindet sich innerhalb eines Gro\systemes von ca. 200 km Seitenlänge, nördlich von ungefähr 39 südlicher Länge. Es wird hier als »Gondwana Region Network« bezeichnet.Ein anderes, südlich des ersteren gelegenes, wird »Patagonien Region Network« genannt. Es ist ebenso rechtwinklig, streicht aber N35W-N55E, mit Gitterabständen von 35 km innerhalb eines Gro\netzes von ca. 140 km Gittergrö\e.Die statistische Betrachtung von 371 Erzlagerstätten, besonders Kupfer, Gold, Blei und Zink, der Gondwana Region zeigt deren Beziehung zu den Netzsystemen: Die gro\en Erzlagerstätten, z.B. Chuquicamata, Salvador, Potrerillos, Agua de Dionisio, Famatina, Pachon-Pelambre, Disputada und Teniente, befinden sich in den gro\en Bruchsystemen mit 100 und 200 km Seitenlänge; das Auftreten von 85 anderen bekannten Erzlagerstätten wird eindeutig von den Netzwerken mit 25 km Seitenlänge kontrolliert; kleinere Lagerstätten sind zufällig, unabhängig von den regmagenetischen Bruchsystemen verteilt.Im Gebiet Patagoniens mit bisher erst 54 ausgewerteten Erzlagerstätten, sind die vier grö\ten Lagerstätten in den 70 und 140 km-Systemen verteilt, zusammen mit einigen kleineren Lagerstätten. Allerdings sind diese kleineren Lagerstätten auch häufig an ein 35 km Raster gebunden.Entsprechend werden 60 % der vormesozoischen Granitoidkörper von den überregionalen Bruchsystemen kontrolliert. Auch ein Zusammenhang von Erdölvorkommen und Uranerzlagerstätten mit den Bruchsystemen kann beobachtet werden.
Resumen El procesamiento estadístico de las megafracturas y lineamientos de los territorios de La Argentina, Chile y Uruguay y la determinación de las orientaciones estructurogenéticas de más de medio centenar de yacimientos minerales filohidrotermales, ha permitido proponer una hipótesis sobre la existencia de dos mallas de fracturamiento planetario en el Cono Sur Sudamericano.Una malla ortogonal, de rumbo N60W-N30E, con equidistancia básica de 25 km, dentro de una red principal de 200 km de lado, ubicada aproximadamente al norte de los 39 de Latitud Sur que denominamos Malla de la Región Gondwánica. La otra, al sur de la anterior. que la designamos como Malla de la Región Patagónica, también ortogonal pero con rumbos N35W-N55E, con equidistancia básica de 35 km, en una red principal de 140 km de lado.El examen estadístico de 371 yacimientos de la Región Gondwánica, principalmente de cobre, oro, plomo y cinc, permite concluir que, en sus relaciones con las mallas propuestas, los Grandes Yacimientos (Chuquicamata, Salvador, Potrerillos, Agua de Dionisio, Famatina, Pachón, Pelambre, Disputada y Teniente) se encuentran muy próximos a las mallas de 100 y 200 km; que los 83 Yacimientos Destacados están claramente controlados por la equidistancia básica de 25 km y que los Yacimientos Menores se distribuyen independientemente de la red regmagénica.En la Región Patagónica, con solo 54 depósitos procesados, los cuatro Yacimientos Destacados se distribuyen practicamente en las mallas de 70 y 140 km junto a parte de los Yacimientos Menores, aunque estos se ajustan más frecuentemente a la alternancia básica de 35 km.De igual manera el 60% de los cuerpos granitoides pre Mesozoicos aparecen controlados por las mallas de fracturamiento supraregional propuestas. También se observa una asimilación a ellas de yacimientos petrolíferos y uraníferos.
, - , 50 . 25 N 60W-N 30E 200 39 . » «., , » «. , N 35W-N 55E 35 140 . 371 , , , , : , .: Chuquicamata, Salvadoe, Potrerillos, Agua de Dionisio, Famatina, Pachon-Pelambre, Disputada Teniente, , 100 200 ; 83 , 25 . . 54 4 , , 70 140 . 35 . 60 % . .相似文献
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