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Anil B. Valsangkar 《Marine Georesources & Geotechnology》2016,34(6):542-549
Regional scale morphological studies on different-sized polymetallic nodules from the Central Indian Basin show that only 2–5 cm sized nodules have highest occurrence per station (92–94% along latitudes; 88–94% along longitudes). A nodule size shows an inverse relationship with the nodule distribution, grade, and abundance. Interestingly, only 3–4 and 4–5 cm sized nodules have highest grade, abundance, and distribution percentages along longitudes in P1, first generation mine site and relinquished area, which further implies that the nodule mining along the longitude would be beneficial. Different-sized nodule groups suggest their formation under variable environmental conditions that existed in the Central Indian Basin. The coexistence of different-sized nodules suggests different environmental conditions existed in the Central Indian Basin. 相似文献
996.
Laboratory Study for Influence of Clay Content (CC) on Wave-Induced Liquefaction in Marine Sediments
B. Liu 《Marine Georesources & Geotechnology》2016,34(3):280-292
In this artice, the influence of clay content on the wave-induced liquefaction in marine sediments was reported. The one-dimensional (1-D) equipment was setup with a vertical cylinder and 1.8–m–thick clayey sandy deposit and 0.2–m–thick water above the deposit. Unlike the previous experimental study for a single soil layer, this study used sand-kaolin mixtures, sand-illite mixtures, and sand-bentonite mixtures as the experimental samples. A series of experiments with 3,000 wave cycles in each test were conducted under numerous wave and soil conditions, which allowed us to examine the influence of clay content (CC) on wave-induced liquefaction in marine sediments. The experimental results showed that the clayey sandy deposit will become prone to liquefaction with the increase of CC when CC is less than a critical value, which depends on the type of clay. However, when CC is greater than the critical value, liquefaction depth will decrease as CC increases. Furthermore, when the CC value reaches a certain level, liquefaction will not occur. For example, no liquefaction occurs when CC ≥ 33% for both kaolin-sand and illite-sand mixtures and CC ≥ 16.36% for bentonite-sand mixtures. 相似文献
997.
E. Yu. Golubkova E. A. Kushim A. B. Kuznetsov A. S. Yanovskii A. V. Maslov S. D. Shvedov Yu. V. Plotkina 《Doklady Earth Sciences》2018,479(1):300-304
The stratigraphic distribution of microfossils and macroscopic fossil biota in Vendian deposits of the South Ladoga region (northwestern East European Platform) is analyzed. In the sequence of the Shotkusa- 1 well, three taxonomically heterogeneous microfossil assemblages are distinguished: two of them refer to the Redkinian age (Starorusskaya Fm.) and one to the Kotlinian age (Vasileostrovskaya Fm.). Deposits of the Starorusskaya Fm. contain Redkinian biota of macroscopic fossils, of which the most characteristic representatives are Chuaria circularis, Doushantuophyton lineare, Morania zinkovi, Orbisiana simplex, and Redkinia spinosa. These new findings expand the paleontological characteristics of Upper Vendian deposits, also providing additional criteria for distinguishing the Redkinian horizon in the northwestern East European Platform. 相似文献
998.
The results of studying Hg in an underwater hydrothermal system in the ocean using the Middle Valley of the Juan de Fuca ridge as an example are presented. A significant part of Hg is accumulated in the basalt fundament (Holes 858F, G), forming anomalously high concentrations (up to 29.30 ppm) in certain parts. The high Hg contents were established in metalliferous sediments (323 ppm) of the sedimentary cover (Hole 858D) and in sulfide deposits (up to 10.30 ppm). In other parts of the section, Hg content is 0.02–0.76 ppm (Holes 858B, D, F), background Hg contents in sediments—0.08–0.28 ppm and in basalts—0.17–0.31 ppm (Holes 855A, C, D). 相似文献
999.
Steshenko E. N. Nikolaev A. I. Bayanova T. B. Drogobuzhskaya S. V. Chashchin V. V. Serov P. A. Lyalina L. M. Novikov A. I. Elizarov D. V. 《Doklady Earth Sciences》2018,479(1):366-370
Doklady Earth Sciences - The rocks and minerals of the Kolvitsa massif are studied by complex isotopic–geochronological and geochemical (U–Pb, Sm–Nd, REE contents of zircons)... 相似文献
1000.
V. S. Belyaev G. S. Bisnovatyi-Kogan A. I. Gromov B. V. Zagreev A. V. Lobanov A. P. Matafonov S. G. Moiseenko O. D. Toropina 《Astronomy Reports》2018,62(3):162-182
The results of MHD numerical simulations of the formation and development of magnetized jets are presented. Similarity criteria for comparisons of the results of laboratory laser experiments and numerical simulations of astrophysical jets are discussed. The results of laboratory simulations of jets generated in experiments at the Neodim laser installation are presented. 相似文献