Deep sea bottom-simulating-reflectors: calibration of the base of the hydrate stability field as used for heat flow estimates

1992 ◽  
Vol 109 (3-4) ◽  
pp. 289-301 ◽  
Author(s):  
R.D. Hyndman ◽  
J.P. Foucher ◽  
M. Yamano ◽  
A. Fisher
Keyword(s):  
Heat Flow ◽  
Deep Sea ◽  
Stability Field ◽  
Sea Bottom ◽  
Bottom Simulating Reflectors ◽  
Hydrate Stability

Heat Flow Calculation Based on Seismic Data

2014 ◽  
Vol 915-916 ◽  
pp. 1202-1206
Author(s):  
Rui Yang ◽  
Neng You Wu ◽  
Yuan Yuan ◽  
Ming Su ◽  
Shao Hua Qiao ◽  
...  
Keyword(s):  
Heat Flow ◽  
Gas Hydrates ◽  
Seismic Data ◽  
Reliable Method ◽  
Three Dimensional ◽  
Flow Calculation ◽  
Bottom Simulating Reflectors ◽  
Main Factors ◽  
Hydrate Stability

Heat flow calculation is a reliable method to estimate the vibration about temperature, main factors of the existence of marine gas hydrates below seafloor. It would increase the accuracy of resources volume estimating and reduce cost of exploration significantly. Depth of Bottom Simulating Reflectors (BSRs), known as the base of gas hydrate stability zone (GHSZ), is a critical variable in this calculation. It should be recognized and mapped using the good quality three-dimensional (3D) pre-stack migration seismic data. By introducing heat flow derived from the depths of BSRs, this method would improve the resolution of the profiles and the quality of imaging and can be used in the specific areas.

V.—Manganese in the Sea

1876 ◽  
Vol 1 (2) ◽  
pp. 50-53 ◽  
Author(s):  
A. H. Church
Keyword(s):  
Chemical Analysis ◽  
Deep Sea ◽  
The Other ◽  
Manganese Nodules ◽  
Red Clay ◽  
Chemical Examination ◽  
Sea Bottom ◽  
Ample Supply

To the geologist, the mineralogist and the chemist, two of the observations made during the voyage of the Challenger are of especial interest. One of these observations is the occurrence over vast areas of the deep sea bottom of a peculiar red clay, containing silica, peroxide of iron, and alumina. The other discovery to which I refer has been described by Sir Wyville Thomson as the occurrence throughout this red clay of nodules of “nearly pure peroxide of manganese.” To these nodules, as well us to the red clay, an organic origin has been assigned. But the immediate source of so much manganese is hard to find, for this element is by no means an abundant constituent of animal or vegetable organisms. The difficulty is, however, somewhat lessened when the manganese nodules are submitted to a more minute chemical examination. From two correspondents I have received an ample supply of these curious concretions, accompanied by a suggestion that they should be submitted to chemical analysis.

On the lack of widespread bottom simulating reflectors in the Mediterranean Basin

2021 ◽  
Author(s):  
Cristina Corradin ◽  
Angelo Camerlenghi ◽  
Michela Giustiniani ◽  
Umberta Tinivella ◽  
Claudia Bertoni
Keyword(s):  
Water Column ◽  
Pore Water ◽  
Mediterranean Basin ◽  
Stability Field ◽  
Hydrocarbon Gases ◽  
Wide Range ◽  
Bottom Simulating Reflectors ◽  
Messinian Evaporites ◽  
The Mediterranean ◽  
The Mediterranean Basin

<p>In the Mediterranean Basin, gas hydrate bottom simulating reflectors (BSR) are absent, with very few and spatially limited exceptions occurring in Eastern Mediterranean mud volcanoes and in the Nile deep sea fan. This is in spite of widespread occurrence of hydrocarbon gases in the subsurface, mainly biogenic methane, from a wide range of stratigraphic intervals.<br>In this study we model the methane hydrate stability field using all available information on DSDP and ODP boreholes in the Western Mediterranean and in the Levant Basin, including the downhole changes of pore water salinity. The models take into account the consequent pore water density changes and use known estimates of geothermal gradient. None of the drilled sites were located on seismic profiles in which a BSR is present.<br>The modelled base of the stability field of methane hydrates is located variably within, below, or even above the drilled sedimentary section (the latter case implies that it is located in the water column). We discuss the results in terms of geodynamic environments, areal distribution of Messinian evaporites, upward ion diffusion from Messinian evaporites, organic carbon content, and the peculiar thermal structure of the Mediterranean water column. <br>We conclude that the cumulative effects of geological and geochemical environments make the Mediterranean Basin a region that is unfavorable to the existence of BSRs in the seismic record, and most likely to the existence of natural gas hydrates below the seabed.<br><br></p>

The improved methods and results of HRBSSS for Mapping the Deep Sea Bottom

2012 ◽  
Vol 131 (4) ◽  
pp. 3489-3489
Author(s):  
Xiaodong Liu ◽  
Weiqing Zhu ◽  
Fangsheng Zhang ◽  
Dongsheng Zhang ◽  
Gaofeng Xu
Keyword(s):  
Deep Sea ◽  
Sea Bottom ◽  
Improved Methods

scholarly journals Gas Seeps at the Edge of the Gas Hydrate Stability Zone on Brazil’s Continental Margin

Geosciences ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 193 ◽  
Author(s):  
Marcelo Ketzer ◽  
Daniel Praeg ◽  
Maria A.G. Pivel ◽  
Adolpho H. Augustin ◽  
Luiz F. Rodrigues ◽  
...  
Keyword(s):  
Gravitational Collapse ◽  
Continental Margin ◽  
Gas Hydrate ◽  
Deep Sea ◽  
Rio Grande ◽  
Cold Seep ◽  
Stability Zone ◽  
The Stability ◽  
Sea Fan ◽  
Hydrate Stability

Gas hydrate provinces occur in two sedimentary basins along Brazil’s continental margin: (1) The Rio Grande Cone in the southeast, and (2) the Amazon deep-sea fan in the equatorial region. The occurrence of gas hydrates in these depocenters was first detected geophysically and has recently been proven by seafloor sampling of gas vents, detected as water column acoustic anomalies rising from seafloor depressions (pockmarks) and/or mounds, many associated with seafloor faults formed by the gravitational collapse of both depocenters. The gas vents include typical features of cold seep systems, including shallow sulphate reduction depths (<4 m), authigenic carbonate pavements, and chemosynthetic ecosystems. In both areas, gas sampled in hydrate and in sediments is dominantly formed by biogenic methane. Calculation of the methane hydrate stability zone for water temperatures in the two areas shows that gas vents occur along its feather edge (water depths between 510 and 760 m in the Rio Grande Cone and between 500 and 670 m in the Amazon deep-sea fan), but also in deeper waters within the stability zone. Gas venting along the feather edge of the stability zone could reflect gas hydrate dissociation and release to the oceans, as inferred on other continental margins, or upward fluid flow through the stability zone facilitated by tectonic structures recording the gravitational collapse of both depocenters. The potential quantity of venting gas on the Brazilian margin under different scenarios of natural or anthropogenic change requires further investigation. The studied areas provide natural laboratories where these critical processes can be analyzed and quantified.

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