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ABSTRACT The polynomial function xky1 (for all integer k and 1 greater than or equal to zero) may be integrated over any surface through a Stokes' Theorem transformation to a line integral around the boundary. An algorithm for the... more
ABSTRACT The polynomial function xky1 (for all integer k and 1 greater than or equal to zero) may be integrated over any surface through a Stokes' Theorem transformation to a line integral around the boundary. An algorithm for the rapid and exact surface integration within any polygonal boundary is derived. Integration of certain of these functions yields area, center of mass, moments of inertia, and higher order statistical moments. In stratigraphical analysis, polynomial trend surfaces may be used to approximate structural surfaces or intervals between these surfaces or other variables of interest. Using the derived algorithm it is possible to compute rapidly the exact volume under the trend surface, within any arbitrary closed polygonal boundary. This volume is of use in itself, or as a measure of goodness-of-fit of the trend surface.
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... east of Cape Costigan, between the Lisan Peninsula and the eastern border fault escarpment, and is herewith named Dale Channel in honor of Lt. John B. Dale, USN. Lt. Dale, who was second-in-command of the US expedition to the River... more
... east of Cape Costigan, between the Lisan Peninsula and the eastern border fault escarpment, and is herewith named Dale Channel in honor of Lt. John B. Dale, USN. Lt. Dale, who was second-in-command of the US expedition to the River Jordan and the Dead Sea, and who ...
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ABSTRACT The Geological Survey of Israel, Historical Productions, Inc., and the Israel Mapping Center have undertaken the production of a new high-resolution digital terrain map (DTM) of Israel. The new DTM is based upon the topographic... more
ABSTRACT The Geological Survey of Israel, Historical Productions, Inc., and the Israel Mapping Center have undertaken the production of a new high-resolution digital terrain map (DTM) of Israel. The new DTM is based upon the topographic information contained in the 10 m contours of the 99 partial or complete 20-km square 1:50,000-scale topographic maps of the Israel Mapping Center. The grid used is 25 m, locked into the Cassini-Soldner projection of the standard Israel Grid. For each of the 1:50,000 topographic sheets, this grid can be visualized as an overlay of one-half millimeter squares, representing 641,601 elevation points per 400 km2 map. An inexpensive PC AT system with EGA graphics and high-resolution digitizer with 16 button cursor is used to edit a matrix of EGA screens of the maps which are scanned using commercial prepress scanners. FORTRAN programs with HALO graphics routines facilitate the editing and directly convert color-coded intervals between contours to a 25 m DTM using weighted means of points interpolated by bicubic splines from both N-S and E-W topographic profiles. Special modules allow inclusion of additional nonstandard contours, spot heights, and profile data, as well as steep discontinuities in the surface to be digitized. The initial use of the DTM elevations will be to enable Historical Productions to calculate the heights of the individual 10 m pixels of a merged SPOT/LANDSAT image mosaic of all of Israel and the adjacent areas for the purpose of producing computer-generated oblique synoptic images of the satellite imagery and thus film or video movies of flight over the animated topography. The DTM and the computer methods used to produce and manipulate it constitute the first stage in a process which will allow representation of physical/geologic/geophysical data for the country in a far more visual and analytic manner. Examples are preparation of slope maps, solid 3-D models, shaded-relief displays, perspective images with quantitative color coding, stereopairs, or even the recontouring of the topography at different intervals or scales. A byproduct of the project is the transfer of digital data from personal computers to Scitex color-separation equipment for inexpensive mass production of high quality color images. An immediate goal is the production of a similar DTM for the adjacent seafloor, prepared from various types of bathymetric observations. This DTM will be converted to an image by shading its slopes according to the sun angle present in the satellite image and coloring the DTM facets (pixels) according to the actual depth, and the image will be transferred to the Scitex equipment for merging with the detailed satellite imagery so as to print satellite images with the associated submarine topography shown as if it were located beneath water of unlimited clarity.
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We use seismic reflection data acquired by a winter-over expedition on drifting sea ice in the central Arctic Ocean to explore a possible spatial and temporal magmatic relation between the sub-bottom geology of part of the deep Arctic... more
We use seismic reflection data acquired by a winter-over expedition on drifting sea ice in the central Arctic Ocean to explore a possible spatial and temporal magmatic relation between the sub-bottom geology of part of the deep Arctic Ocean and the Mesozoic volcanic rocks found on the islands and the bordering continental shelf of Franz Josef Land and Svalbard? The new data set from the North American segment (85 o – 90 o N) of the Lomonosov Ridge, central Arctic Ocean documents several Mesozoic volcanic pulses over a distance of ˞600 km along the ridge. This volcanism borders a domain of high magnetic field intensity over the adjacent Alpha Ridge in the deep basin where the magnetic source rocks and recent seismic reflection data indicate extensive Mesozoic magmatism. We suggest the Mesozoic volcanism on the Lomonosov Ridge in its paleo-position at the former continental margin north of Franz Josef Land and Svalbard spatially link the Mesozoic magmatic pulses of the continental High Arctic Large Igneous Province (HALIP) of polar Europe to volcanism on the adjacent Alpha Ridge in the deep Arctic Ocean. Increased input of heat to the upper crust on the Lomonosov Ridge enhanced maturation of hydrocarbon source rocks as manifested by the presence of gas/fluid escape pipes restricted to the area of volcanism.
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A hovercraft-based ice drift station gives researchers access to previously inaccessible regions of the changing Arctic sea ice cover off the coast of Greenland.
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A global system of geosutures was identified. These form a major counterclockwise converging spiral pattern whose ‘eye’ stretches along the Alpine‐Himalayan orogenic belt. The system of lithospheric slices, which are bounded by these... more
A global system of geosutures was identified. These form a major counterclockwise converging spiral pattern whose ‘eye’ stretches along the Alpine‐Himalayan orogenic belt. The system of lithospheric slices, which are bounded by these geosutures, approaches the Alpine‐Himalayan ‘eye’in different ways: the slices converging from the south collide frontally, whereas the northern ones tangentially and sequentially slide along one another. Another smaller clockwise converging spiral pattern was identified close to the earth's north pole. In addition to the Alpine‐Himalayan belt, many other important tectonic features appear to be associated with the geosutures of the proposed system, thereby offering explanations for their genesis. The correlation between some of the geosutures and hydrocarbon accumulations as well as metallic ore deposits may stimulate new concepts and leads for economic explorations elsewhere. Another system of geosutures of planetary dimensions was also noticed on Mars. The largest spiral pattern converges counterclockwise on an ‘eye’ located along the Martian equator. Two smaller spiral patterns were also noticed on both poles of Mars. The northern spiral is clockwise, while the southern one is counterclockwise. If the Martian spirals are indeed analogous to those on earth, then a third spiral showing counterclockwise convergence may exist close to the earth's south pole. The coherence and smoothness of the newly identified patterns on earth build confidence in their reliability. Once the kinematics involved in this system are understood, we expect that their origin will also be deciphered. However, this last is beyond the scope of the present paper.
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The Dead Sea is the world’s lowest water body and among the saltiest (330ppt). To enable multi-beam coverage of this historical lake, ELAC Nautik took up the challenge of modifying their SeaBeam 1050 multi-beam to deal with extreme sound... more
The Dead Sea is the world’s lowest water body and among the saltiest (330ppt). To enable multi-beam coverage of this historical lake, ELAC Nautik took up the challenge of modifying their SeaBeam 1050 multi-beam to deal with extreme sound speeds by introducing a firmware ‘tweak’ changing the beamforming direction to account for a higher sound speed which was at that time not exactly known. While data acquisition was possible, initial results showed severe refraction issues that required a complicated procedure of ‘de-tweaking’ and re-computing
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Digital sediment sub-bottom profiler data (PARASOUND system) from the Israeli continental shelf and slope show an upper sediment wave field (SWF) in water depths of 80-140 m and a lower SWF between 190 and 350 m between Gaza and Haifa of... more
Digital sediment sub-bottom profiler data (PARASOUND system) from the Israeli continental shelf and slope show an upper sediment wave field (SWF) in water depths of 80-140 m and a lower SWF between 190 and 350 m between Gaza and Haifa of more than 100 km length. Both SWFs reveal thicknesses of up to 16 m and a width of more than 5 km. The wave amplitudes are up to 4 m. The apparent wave length of the upper SWF varies between 560 to 570 m and that of the lower SWF between 390 and 420 m. An erosive or winnowed 2.5 km wide zone with reduced sediment thickness and little or no internal stratification occurs between 140 m and 190 m between the SWFs and parallels the bathymetric contours. The PARASOUND data show that the sediment waves grow and migrate slightly upslope. A swath sounder survey confirmed that the ridge crests strike parallel to the trend of the outer shelf. The striking direction proves that the causative current arrives from the west and that the waves are not a consequenc...
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New Multibeam bathymetric and sediment profiler data from the Chukchi Borderland provide pieces to the Arctic Ocean glacial puzzle
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su.se. ...
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s, Israel. Geol. Soc., Jerusalem, p. 9-10. Druckman, Y., 1969. The petrography and environment of deposition of the Triassic Saharonim Formation and the Dolomite Member of the Mohilla Formation in Makhtesh Ramon, Central Negev (southern... more
s, Israel. Geol. Soc., Jerusalem, p. 9-10. Druckman, Y., 1969. The petrography and environment of deposition of the Triassic Saharonim Formation and the Dolomite Member of the Mohilla Formation in Makhtesh Ramon, Central Negev (southern Israel). Isr. Geol. Surv. Bull., 49, 24 p. Druckman, Y., 1976. The Triassic in southern Israel and Sinai: A sedimentological model of marginal epicontinental marine environments. Ph.D. Thesis, Hebrew Univ. Jerusalem, 188 p. Also: Isr. Geol. Surv., Rep. OD/1/76. (In Hebrew; Engl. Abstr.). Druckman, Y., 1974a. The stratigraphy of the Triassic sequence in southern Israel. Isr. Geol. Surv. Bull., 64, 94 p. Druckman, Y., 1974b. Triassic Paleogeogeography of Southern Israel and the Sinai Peninsula. Die Stratigr. Der Alpin-Mediterranen Trias, Symp. Wien, May 1973. Oesterreichische Akademie der Wissenschaften, Schriftenreihe der Erdwissenschaftliche Kommissionen, 2, p 79-86. Druckman, Y., 1984. Evidence for early-Middle Triassic Faulting and possible rifting...
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... Aharon (Ronnie) Sade,a Gideon Tibor,b John K. Hall,c,* Moti Diamant,d Hadar Sade,a Gal Hartman,a,b Gideon Amit,b Boris Schulze ... The second survey (Ben-Avraham et al., 1990) was carried out in 1986 and 1987 along mutually... more
... Aharon (Ronnie) Sade,a Gideon Tibor,b John K. Hall,c,* Moti Diamant,d Hadar Sade,a Gal Hartman,a,b Gideon Amit,b Boris Schulze ... The second survey (Ben-Avraham et al., 1990) was carried out in 1986 and 1987 along mutually perpendicular N–S and E–W lines with 100 m ...
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Sub-bottom sediments within a 200 x 600 km area on the crest and south slope (water depth 1200-2500 meter) of the submarine Alpha Ridge in the central Arctic Ocean have been locally disrupted down to at least 500 meter below the seabed,... more
Sub-bottom sediments within a 200 x 600 km area on the crest and south slope (water depth 1200-2500 meter) of the submarine Alpha Ridge in the central Arctic Ocean have been locally disrupted down to at least 500 meter below the seabed, suffered intensive local current erosion, and abundant mass wasting. There appears to be a westward progression along the ridge from an eastern area of chaotic and eroded sub-bottom sediments to proximal intense erosion of an undisturbed section and a more distal occurrence of mass wasting and minor erosion. As a working hypothesis, we propose that the spectrum and scale of drastic, spatially restricted and apparently geologically short-lived environmental changes are compatible with the effect of a shock wave from the impact of an extra-terrestrial body into the central Arctic Ocean.
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Abstract This study synthesizes 15 years (2001–2016) of detailed multibeam hydrographic mapping covering the entire 26,500 km2 of the Israeli Exclusive Economic Zone (EEZ). Multibeam data were collected on-board three research vessels... more
Abstract This study synthesizes 15 years (2001–2016) of detailed multibeam hydrographic mapping covering the entire 26,500 km2 of the Israeli Exclusive Economic Zone (EEZ). Multibeam data were collected on-board three research vessels across the continental shelf, slope, and the deep Levant basin; between water depths of about 15 m to 2100 m. Single-channel 3.5 kHz seismic reflection chirp profiles were collected simultaneously with the multibeam surveys in selected parts of the area. The new data enabled the first comprehensive quantitative seafloor morphological analysis of the slope and deep basin. Using GIS techniques on the high-resolution multibeam data, we analyze the spatial distribution and quantitatively describe the seafloor morphologies in detail. High-resolution chirp seismic profiles demonstrate the underlying shallow structure. Results indicate that the seabed comprises five main morphologies: folds, faults, sediment waves, deepwater channels, and sediment fan lobes. Quantitative morphological analysis and seismic data interpretation were used to derive field relations between these morphologies, which along with previously collected multi-channel seismic reflection data, suggest that a concentric fold geometry formed around the Nile outlet during the late Pliocene to early Pleistocene, as part of a general thin-skin radial salt-tectonic deformation above the Messinian mobile unit. This radial motion was accompanied by displacement along NNE-trending strike-slip faults in the basin, and an extensional component across E-W trending strike-slip faults along the Levant margin. While some of these displacements continue to deform the modern seabed (across Area A), others are covered by a wedge of Quaternary deposits, mainly in the northeastern part of the basin (Area B). Areas A and B also differ in grain size distribution, as indicated by backscatter analysis of the multibeam data. These observations divide the Israeli EEZ into two distinct areas: (Area A) Nile derived siliciclastic sediments transported directly into the deep basin via confined (forming meandering channels and overbank deposits) and unconfined flows (forming fans and lobes). The wedge consisting of Area B was fed by erosion products of the Nile outlet that were transported northwards along the continental shelf by seafloor currents of the Levant Jet System, and glided down the northern Levant continental slope as turbidity currents. This supply built at least seven sequences of Quaternary sediment waves that form upslope migrating cyclic steps. The complete data coverage and quantitative morphological analysis presented here introduce new spatial and temporal constraints that call for a reexamination of previous seabed sampling locations not accounting for detailed bathymetry, and to augment future seabed sampling efforts, understanding the sediment supply paths across the basin, and the geomorphological footprint of salt tectonics processes.
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Abstract A precipitous submarine horst is located between Sinai Peninsula and Tiran Island, but also between Hume Deep (1400 m) in northernmost Red Sea and Tiran Deep (1400 m), in the southernmost Gulf of Elat. The horst outcrops above... more
Abstract A precipitous submarine horst is located between Sinai Peninsula and Tiran Island, but also between Hume Deep (1400 m) in northernmost Red Sea and Tiran Deep (1400 m), in the southernmost Gulf of Elat. The horst outcrops above sealevel in places, where corals built small reefs, trending NNE-SSW. The horst forms a structural transfer zone trending NNE-SSW and constrained by series of normal faults on both flanks. Transfer zones were repeatedly encountered to separate between axial grabens along regional rifts in East Africa and elsewhere while similar structures were observed in analog models. Transfer zones between grabens along axial rifts were attributed to oblique extension, consequently the occurrence of the Tiran transfer zone could indicate that geodynamic regime of oblique extension prevails in the northern Red Sea and exists also in Elat Rift. Tiran horst is structurally associated with the arcuate system of grabens and elongated salt diapirs that were encountered in the bathyal northern Red Sea, which swings from the Red Sea NW-SE orientation to the N-S trend of Elat Rift. The age of the initiation of the rifting and the contemporaneous ascent of its margin was attributed to late Miocene – early Pliocene, as indicated by extensive series of coralline terraces and by non-branching fluvial system on Tiran Island. The research did not encounter supporting evidence that the Elat Rift is a transform fault that branched off the Red Sea during the early-middle Miocene nor that Tiran Deep is a pull-apart basin.