48 research outputs found

    Origin and kinematics of a basin-scale, non-polygonal, layer-bound normal fault system in the Levant Basin, eastern Mediterranean

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    Polygonal, layer-bound normal faults can extend over very large areas (>2,000,000 km2) of sedimentary basins. Best developed in very fine-grained rocks, these faults are thought to form during early burial in response to a range of diagenetic processes, including compaction and water expulsion. Local deviations from this idealised polygonal pattern are common; however, basin-scale, layer-bound faults with non-polygonal map view are not well-documented and accordingly, their genesis is not well understood. In this study, we use 3D seismic reflection data, biostratigraphy and well logs from the Southern Levant Basin, offshore Israel, to develop an age-constrained seismic-stratigraphic framework and determine the geometry and kinematics of such basin-scale fault system. The faults tip out downwards along an Eocene Unconformity, but unlike layer-bound faults in the Northern Levant Basin, they do not reach the base of the Messinian evaporites, instead tipping out upwards at the top Langhian. On average, the faults in the Southern Levant Basin are 6.3 km long, have an average throw of 120 m, and consistently strike NW-SE. Throw-depth plots, accompanied by thickness changes, indicate that the faults accumulated growth strata during the Late Burdigalian and are spatially and kinematically associated with a WSW-ESE-striking strike-slip fault. Unlike true polygonal faults, these faults propagated through ca. 2 km-thick sandstone-prone Oligocene-Miocene strata. Whereas previous studies from the Northern Levant Basin associate fault nucleation and growth with burial-related diagenesis, the sandstone-prone character of the Oligocene-Miocene suggests that this process cannot be readily applied to the Southern Levant Basin. Instead, we highlight potential tectonic events that occurred during and may have triggered thin-skinned extension at times of fault growth

    Conference of Soviet and American Jurists on the Law of the Sea and the Protection of the Marine Environment

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    Included in the papers for the Conference of Soviet and American Jurists on the Law of the Sea and the Protection of the Marine Environment: Introduction by Milton Katz and Richard R. Baxter, p. 1 Freedom of Scientific Research in the World Ocean by A.F. Vysotsky, p. 7 The International Law of Scientific Research in the Oceans by Richard R. Baxter, p. 27 Responsibility and Liability for Harm to the Marine Environment by Robert E. Stein, p. 41 Liability for Marine Environment Pollution Damage in Contemporary International Sea Law by A. L. Makovsky, p. 59 Protection of the Marine Environment from Pollution by Richard A. Frank, p. 73 The Freedom of Navigation and the Problem of Pollution of the Marine Environment by V. A. Kiselev, p. 93 The Freedom of Navigation Under International Law by William E. Butler, p. 107 International Fisheries Management Without Global Agreement: United States Policies and Their Impact on the Soviet Union by H. Gary Knight, p. 119 Some Biological Background for International Legal Acts on Rational Utilization of the Living Resources of the World Ocean by P. A. Moiseev, p. 143 An International Regime for the Seabed Beyond National Jurisdiction by Thomas M. Franck, p. 151 Settlement of Disputes Under the Law of Ocean Use, with Particular Reference to Environmental Protection by John Lawrence Hargrove, p. 18

    Preliminary video-spatial analysis of cold seep bivalve beds at the base of the continental slope of Israel (Palmahim Disturbance)

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    Seafloor video surveys were carried out with the ROV Max Rover in the Palmahim Disturbance (PD) area, offshore Israel, in September 2016 during the EUROFLEETS2 SEMSEEP cruise on board the R/V AEGAEO. Preliminary observations of distribution and frequencies of bivalve accumulations show that they are mostly composed by Lucinoma kazani shells. Valves are distributed mainly along the base of authigenic carbonate crusts, in association with bacterial mats and inside inactive chimney-like structures, sometimes associated with crabs and living tubeworms. However, no living molluscs were observed.The relation between distribution of bivalve beds and seepage activity is not straightforward in the PD area. However, the presence of these accumulations and the size of L. kazani, suggest that seepages may have lasted for at least one decade, before its reduction/cessation that induced L. kazani mortality. The presence of few articulated valves of this species indicates that they were alive up to one year before the ROV observations and their different preservation state may imply different seepage phases. This research shows that chemosymbiotic benthic communities may be used as a proxy for better understanding the past dynamics of fluid emissions at the seafloor. However, further quantitative studies are needed to confirm these observations

    Late Holocene pteropod distribution across the base of the south-eastern Mediterranean margin: the importance of the <i>&gt;</i>&thinsp;63&thinsp;µm fraction

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    Euthecosomata pteropods were analysed in core sediments collected in the framework of the 2016 EUROFLEETS2 SEMSEEP cruise, offshore of Israel, in the eastern Mediterranean Sea. The investigated cores were retrieved in a deep-sea coral area at 690 m depth, an actively methane-seeping pockmark area at 1038 m depth, and a deep-sea channel area at 1310 m water depth. We identified and documented the pteropod species belonging to the families Heliconoididae, Limacinidae, Creseidae, Cavoliniidae, Cliidae, and Hyalocylidae and to some heteropods. Our study highlights the importance of investigating pteropods in the size fractions &gt; 63 µm instead of the &gt; 125 µm only. In particular, neglecting the small size fraction may result in a remarkable (up to 50 %–60 %) underestimation of the relative abundance of the epipelagic species Creseis acicula and Creseis conica and the mesopelagic species Heliconoides inflatus. This may significantly affect palaeoenvironmental reconstructions. The observed presence of tropical species supports the suggestion that the eastern Mediterranean is a refugium for these species. This study provides a basic benchmark for the late Holocene evolution of pteropod and heteropod distribution over 5800–5300 cal BP across the base of the south-eastern Levantine margin.</p

    Macro- and micro-fauna from cold seeps in the Palmahim Disturbance (Israeli off-shore), with description of Waisiuconcha corsellii n.sp. (Bivalvia, Vesicomyidae)

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    Chemosymbiotic micro- and macro-fauna related to cold-seep sites were recovered in the Palmahim Disturbance (PD), offshore Israel, during EU EUROFLEETS2 SEMSEEP Cruise, by box-coring and Remotely Operated Vehicle (ROV) dives. No live macrofauna was identified in the collected sediments, with the exception of the seep-related crustacean Calliax lobata (de Gaillande and Lagardère, 1966). Numerous Calliax claws testify the past colonization of these soft bottoms by several generations of this ghost shrimp. After sediment sieving on 1 mm, we identified gastropods belonging to the families Trochidae, Eucyclidae, unassigned Seguenzioidea (genus Anekes), Rissoidae, Elachisinidae, Raphitomidae, Mangeliidae, Architectonicidae, Orbitestellidae, and Acteonidae. The identified bivalves belong to the families Nuculidae, Yoldiidae, Mytilidae, Lucinidae, Thyasiridae, Semelidae, Kelliellidae, Vesicomyidae, Xylophagidae, and Cuspidariidae. A seep-related group of chemosymbiotic molluscs was detected, including: Taranis moerchii (Malm, 1861), Lurifax vitreus Warén and Bouchet, 2001, Idas ghisottii Warén and Carrozza, 1990, Lucinoma kazani Salas and Woodside, 2002, Thyasira biplicata (Philippi, 1836), Isorropodon perplexum Sturany, 1896, and the newly described Vesicomyid species Waisiuconcha corsellii n. sp., that represents also the first record of the genus Waisiuconcha in recent Mediterranean sediments.The ROV dives recorded local patches of several m2 of seafloor covered by dead shells of L. kazani, with a density of up to about 200 loose shells per square meter. The potential occurrence of seep-related foraminifera, among low-oxygen tolerant species, was explored by comparison with previously sampled adjacent localities, and lead to the identification of Chilostomella oolina, Globobulimina affinis and G. pseudospinescens as potential foraminiferal seep indicators in the southeastern Mediterranean Sea. The absence of live, seep-related fauna in surface sediments in the PD, where seepage has been confirmed, suggests intermittent activity and a pause or decline of the investigated seeps

    Late Paleocene to middle Eocene carbon isotope stratigraphy of the Northern Negev, Southern Israel: potential for paleoclimate reconstructions

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    Sedimentary records depicting significant variability in climate and carbon cycling across the early Paleogene have emerged over the last two decades. Continuous, long-term, high-resolution records mostly derive from deep-sea drill cores, and only few derive from continental margin locations. Here we examine lower Paleogene marls and chalks collected from a core (RH-323) in the Northern Negev Desert (Southern Israel). The studied sediments accumulated on a continental slope of the southern Tethys at ~500–700 m paleodepth and did not undergo deep burial. We analyzed bulk carbonate stable carbon and oxygen isotopes and bulk magnetic susceptibility. The resulting records can be aligned with those from elsewhere and include the Paleocene Carbon Isotope Maximum (PCIM), Paleocene Eocene Thermal Maximum (PETM) and Early Eocene Climatic Optimum (EECO). An obvious realization is a concurrence between local lithological variations and major climate and carbon cycle changes. This has been highlighted for sedimentary sequences elsewhere, but the relations differ in the Negev, such that carbonate rich intervals mark the PCIM and PETM, and a transition from marl to chalk initiates the EECO. Overall, the relatively pristine and immature sediment records in southern Israel likely provide potential for high-resolution paleoclimate and carbon cycle reconstructions during a crucial time interval and in a crucial part of the world

    Late Paleocene to middle Eocene carbon isotope stratigraphy of the Northern Negev, Southern Israel: potential for paleoclimate reconstructions

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    Sedimentary records depicting significant variability in climate and carbon cycling across the early Paleogene have emerged over the last two decades. Continuous, long-term, high-resolution records mostly derive from deep-sea drill cores, and only few derive from continental margin locations. Here we examine lower Paleogene marls and chalks collected from a core (RH-323) in the Northern Negev Desert (Southern Israel). The studied sediments accumulated on a continental slope of the southern Tethys at ~500–700 m paleodepth and did not undergo deep burial. We analyzed bulk carbonate stable carbon and oxygen isotopes and bulk magnetic susceptibility. The resulting records can be aligned with those from elsewhere and include the Paleocene Carbon Isotope Maximum (PCIM), Paleocene Eocene Thermal Maximum (PETM) and Early Eocene Climatic Optimum (EECO). An obvious realization is a concurrence between local lithological variations and major climate and carbon cycle changes. This has been highlighted for sedimentary sequences elsewhere, but the relations differ in the Negev, such that carbonate rich intervals mark the PCIM and PETM, and a transition from marl to chalk initiates the EECO. Overall, the relatively pristine and immature sediment records in southern Israel likely provide potential for high-resolution paleoclimate and carbon cycle reconstructions during a crucial time interval and in a crucial part of the world

    Seismology Across the Northeastern Edge of the Tibetan Plateau

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    On 12 May, a great earthquake (Ms = 8.0) on the Longmenshan thrust fault rumbled through China's Sichuan province, killing more than 69,000 people and injuring 374,000. The Longmenshan thrust is part of the eastern border of the Tibetan Plateau, but it is not the plateau's only restless margin. An even larger earthquake (Ms = 8.1) on the Kunlun fault shook northeastern Tibet in 2001, fortunately in a sparsely populated area. These massive quakes underscore the importance of understanding the tectonic response of Asia to collision by India
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