Showing papers in "Marine Geology in 1991"

TL;DR: Isotope paleontology uses the isotopic composition of fossil remains of organisms to make inferences about the physical surroundings of growth of the organisms (especially temperature), and to obtain clues about life history and modes of growth.

TL;DR: In this paper, sediment accumulation in the Yellow Sea epicontinental-shelf environment was investigated on 100-yr and 1000-yr time scales using 210Pb and 14C geochronologies.

TL;DR: In this paper, a simple semi-empirical backscattering theory has been developed to predict the form of the scattered signal and comparisons have been made of the concentrations predicted from the theory against concentration measurements made in laboratory tanks.

TL;DR: In this paper, the mechanisms responsible for onshore and offshore sediment fluxes across the shoreface zone seaward of the surf zone were examined in a 3-year field study in the Middle Atlantic Bight in the depth region 7-17 m using instrumented tripods supporting electromagnetic current meters, pressure sensors, suspended sediment concentration sensors, and sonar altimeters.

TL;DR: In this paper, the authors describe the Cenozoic sequences using two general categories based on their acoustic geometries: type IIA and type I sequences, which are commonly located near the seaward edges of major Mesozoic and older margin structures.

TL;DR: A computer mapping system was employed to document the location of 259 shoreface-attached and detached sand ridges along U.S. Atlantic barrier island and cape coastlines as mentioned in this paper.

TL;DR: A seismic survey to resolve the geometry of major incisions within the Upper Pleistocene has been run over an area of 1600 km2 in the mid-North Sea as mentioned in this paper.

TL;DR: ChristChristie-Blick et al. as mentioned in this paper showed that onlap and offlap are due to lateral migration of a "line of critical bypassing", defined so as to incorporate the effects of sediment loading and compaction as well as the rate of change of elevation with respect to sea level.

TL;DR: A comparative study of the mineralogy and geochemistry of sulfide deposits on mid-ocean ridges in the Northeast Pacific and the Mid-Atlantic reveals common characteristics associated with primary gold enrichment as mentioned in this paper.

TL;DR: In this article, the authors used acoustic backscatter measurements of the concentrations of sand in suspension on the shoreface, seawards of the breaking zone, during a mild storm event to show that sand concentrations increase initially but then rapidly decrease as the wave energy increases.

TL;DR: In this paper, the authors have shown that in the Gulf of Trieste, the northernmost part of the Mediterranean Sea, a ∼ 20 m deep marine basin influenced by freshwater inflow, bottom sediment resuspension and increasing pollution, the surficial sediments can be subdivided into seven zones on the basis of grain size and mineral composition.

TL;DR: In this paper, a high-resolution sampling study has been undertaken in order to investigate whether the Ba distribution in sapropels reflects a primary input signal or whether it has been altered by diagenetic processes.

TL;DR: Tidal resuspension experiments were carried out on two occasions during the winter of 1988-1989 at a disposal site for hydraulically dredged sediments in northern Chesapeake Bay to determine the influence of tidal ressuspension on erosion of recent deposits as discussed by the authors.

TL;DR: In this paper, the authors observed the migration of a gravel barrier at 8 m a −1 landward over back-barrier mud, following abandonment of part of the barrier volume on the shoreface.

TL;DR: In this article, the regional variations in clay-mineral concentrations in 39 turbidite-free and undisturbed deep-sea sediment cores from the Arabian Sea are compared with distribution patterns of claymineral accumulation rates during the Holocene and the last glaciation.

TL;DR: In the Eel River basin in offshore northern California between 40°38′ and 40°56′ N, gas hydrates contained primarily methane (δ13C = −57.6 to −69.1‰) and occurred as dispersed crystals, small (2-20 mm) nodules, and layered bands within the sediment as discussed by the authors.

TL;DR: In this paper, two cores recovered in the eastern Mediterranean were analyzed for major, minor and trace elements, and the primary chemical composition of the sediment is different at each location, probably because the lithological sources and the relative biogenic contributions differ.

TL;DR: In this paper, multichannel seismic investigations showed the presence of a large trough-mouth fan deposit on the continental margin in the southern Weddell Sea, and the seismic stratigraphic evidence suggests that the submarine fan is largely composed of glacigenic sediments.

TL;DR: In this article, the variability of sediment flux in the Norwegian and the Labrador seas as a function of paleoceanographic and paleoclimatic changes has been investigated, and it has been shown that minor amounts of coarse terrigenous particles occur in sediments that were deposited between 9.5 and 7.0 Ma, recording a nearly simultaneous onset of large-scale ice rafting.

TL;DR: In this article, the authors interpreted the emergence of two rapid uplifts during the late Holocene rather than representing eustatic fluctuations of climatic origin as claimed by previous authors in other areas of the eastern Mediterranean.

TL;DR: In this paper, a study to test the effectiveness of satellite data for monitoring shoreline change is reported, the rapidly changing Rosetta Promontory of the Nile Delta, Egypt, being selected as the study area.

TL;DR: In this paper, a geochemical analysis of surficial sediment in the Gulf of Trieste, in terms of organic carbon, total nitrogen and phosphorus 13C composition of sedimentary organic matter, the trace metals Hg, Pb, Cr, Cu, Zn, Cd, Ni, Mn and Fe, and the radionuclides 137Cs and 210Pb were carried out.

TL;DR: In this article, the authors used seismic reflection profiles to map the Messinian erosion surface and associated basin-margin deposits on the continental margin off Nice, and then used a palaeogeographic reconstruction of the area.

TL;DR: In this paper, the authors consider the effects of the beachrock formation on the development of low-latitude coastlines and propose a model of horizontal shoreline displacement and coastal evolution, which takes into account the effective reduction of littoral sand supply.

TL;DR: The Gulf of Patras is an actively subsiding late Cenozoic graben in western Greece that receives deltaic sediment from the large Acheloos and Evinos rivers.

TL;DR: The Mariana forearc is a non-accretionary forearc with numerous seamounts as discussed by the authors, and the presence of aragonite and calcite indicates a nonvolcanic origin.

TL;DR: For example, at the High Energy Benthic Boundary Layer Experiment (HEBBLE) site at 4820 m depth on the Nova Scotia Rise (40°27′N, 62°20′W), abundances of polychaetes, bivalves, tanaids, and isopods were conspicuously greater than expected for the depth, whereas those of nematodes and harpacticoid copepods, the two dominant meiofaunal taxa, were not as discussed by the authors.

TL;DR: Oxygen and carbon isotopic variability of the dominant carbonate fraction within bedded, organic-carbon rich Lower Cretaceous sediment intervals from various DSDP sites are closely correlated with preservational changes in the carbonates.

TL;DR: A transfer function (PDU 1) relating modern marine diatom sediment surface assemblages to a 10-year averaged surface water primary productivity map spanning a range of 0.1-1.0 g C/m2/day is used to interpret downcore variation in productivity at three sites (Site 680, 681 and 686) of ODP Leg 112 off Peru as discussed by the authors.

TL;DR: Several volcanic ash layers were identified in cores collected in the Bannock Basin (Eastern Mediterranean) during cruises BAN-84, BAN86, X-2 and W-1 of the R.V.Bannock as mentioned in this paper.