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1. |
Marine Sand Resources Offshore Israel |
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Marine Georesources & Geotechnology,
Volume 18,
Issue 1,
2000,
Page 1-42
Gideon Almagor,
Dan Gill,
Ithamar Perath,
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摘要:
The continental margin of northern Sinai and Israel, up to Haifa Bay, is the northeastern limb of the submarine Nile Delta Cone. It is made up predominantly of clastics from the Nile and its predecessors. The continental shelf and coastal plain of Israel are built of a series of shore-parallel ridges composed of carbonate-cemented quartz sandstone (locally named kurkar), a lithification product of windblown sands that were piled up into dunes during the Pleistocene. The drop in global sea level and regression during the last glacial period exposed the continental shelf to subaerial erosion and created a widespread regional erosional unconformity which is expressed as a prominent seismic reflector at the top of the kurkar layers. The subsequent Holocene transgression abraded much of the westernmost kurkar ridges, drowned their cores, and covered the previous lowstand deposits with marine sands, which were in turn covered by a sequence of sub-Recent clayey silts.
ISSN:1064-119X
DOI:10.1080/10641190009353781
出版商:Taylor & Francis Group
年代:2000
数据来源: Taylor
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2. |
Morphological Features of Co-Rich Manganese Deposits and Their Relation to Seabed Slopes |
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Marine Georesources & Geotechnology,
Volume 18,
Issue 1,
2000,
Page 43-76
Tetsuo Yamazaki,
Rahul Sharma,
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摘要:
The morphological features associated with Co-rich manganese deposits, the size variations of nodules, and the occurrence of different substrates have been analyzed, to evaluate the influence of various seabed slope angles on the distribution of these features. The coverage and size of the crusts depend on their surface morphology and seabed topography, resulting in cobble-type, lineated, or step-like outcrops. Small nodules (1–4 cm in diameter) dominate all seabed slopes, with a few locations having nodules ranging from 1 to 8 or 1 to 10 cm. Sediments invariably occur as substrates for nodules and as cover for crusts, their coverage being inversely proportional to that of the nodules and crust outcrops.
ISSN:1064-119X
DOI:10.1080/10641190009353782
出版商:Taylor & Francis Group
年代:2000
数据来源: Taylor
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3. |
Hydrothermal Mineralizing Processes and Associated Sedimentation in the Santorini Hydrothermal Embayments |
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Marine Georesources & Geotechnology,
Volume 18,
Issue 1,
2000,
Page 77-118
D.S. Cronan,
S.P. Varnavas,
R. Hodkinson,
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PDF (2207KB)
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摘要:
Seven sediment cores from the Palaea and Nea Kameni hydrothermal embayments (PK and NK) on Santorini have been studied by using sediment smear slides, X-ray diffraction, and radiocarbon techniques to determine their lithology, mineralogy, and age, respectively. The cores have been analyzed chemically for a suite of elements, including selective chemical leaching, to determine the partition of elements between coexisting phases. Lithologically and chemically, the sediments from the two embayments are very different. Sediments from PK are oxidized in the upper parts of the cores and reduced at depth; they comprise mainly hydrothermal pyritiferous diatomaceous ooze with minor Fe oxyhydroxide, volcanic debris, gypsum, and siderite. Sediments from NK are oxidized throughout and comprise predominantly amorphous iron oxyhydroxides and goethite; they are thought to have formed by direct precipitation from solution. In PK, biogenic, detrital seawater evaporate, and hydrothermal sediment phases have been identified but only the detrital inputs can be correlated between cores. Mn shows a pronounced enrichment towards the outer part of the embayment because of its dispersion down the embayment and precipitation in the more-oxidizing sediments towards the open sea. In NK, the sediments contain detrital, seawater evaporate, and hydrothermally precipitated and scavenged phases. The presence of substantial amounts of organic matter in the PK sediments but not in the NK sediments is probably the main reason why geochemical processes in the two embayments are different.
ISSN:1064-119X
DOI:10.1080/10641190009353783
出版商:Taylor & Francis Group
年代:2000
数据来源: Taylor
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