scholarly journals Indications for the Occurrence of Gas Hydrates in the Fram Strait from Heat Flow and Multichannel Seismic Reflection Data

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
W. H. Geissler ◽  
P. V. Pulm ◽  
W. Jokat ◽  
A. C. Gebhardt
Keyword(s):  
Heat Flow ◽  
Gas Hydrates ◽  
Seismic Data ◽  
Sedimentary Basins ◽  
Slope Instability ◽  
Western Slope ◽  
Fram Strait ◽  
Flow Data ◽  
Seismic Reflection Data ◽  
Yermak Plateau

The distribution of gas hydrates recently raised increased attention, especially along glaciated continental margins, due to its potential importance for slope stability and global climate. We present new heat flow data together with multichannel reflection seismic data from the central Fram Strait in-between Northeast Greenland and Svalbard. This area is only accessible by icebreaking vessels, and, therefore, knowledge about this area is still sparse. The new heat flow data concur with previous measurements in the region. High temperature gradients of >200 mK/m were recorded along the active spreading zone in the Fram Strait, and gradients of 75 mK/m along the western slope of Yermak Plateau. Along the Northeast Greenland slope, the measured gradients reach 54 mK/m at maximum. Seismic data image bottom-simulating reflections proofing that the known gas-hydrate province spreads much further north along the western slope of the Yermak Plateau than previously known. Existing slide scars indicate that there might be a causal relationship between the occurrence of gas hydrates and slope instability in that area. Along the Northeast Greenland continental margin and in the adjacent abyssal plain, strong indications for the occurrence of gas within the sedimentary basins and for its migration along fault zones and chimney-like structures are found.

scholarly journals Arctic megaslide at presumed rest

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Wolfram H. Geissler ◽  
A. Catalina Gebhardt ◽  
Felix Gross ◽  
Jutta Wollenburg ◽  
Laura Jensen ◽  
...  
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Seismic Data ◽  
Slope Failure ◽  
Slope Instability ◽  
Stability Zone ◽  
Gas Reservoir ◽  
Methane Seepage ◽  
Failure Event ◽  
Hydrate Stability

Abstract Slope failure like in the Hinlopen/Yermak Megaslide is one of the major geohazards in a changing Arctic environment. We analysed hydroacoustic and 2D high-resolution seismic data from the apparently intact continental slope immediately north of the Hinlopen/Yermak Megaslide for signs of past and future instabilities. Our new bathymetry and seismic data show clear evidence for incipient slope instability. Minor slide deposits and an internally-deformed sedimentary layer near the base of the gas hydrate stability zone imply an incomplete failure event, most probably about 30000 years ago, contemporaneous to or shortly after the Hinlopen/Yermak Megaslide. An active gas reservoir at the base of the gas hydrate stability zone demonstrate that over-pressured fluids might have played a key role in the initiation of slope failure at the studied slope, but more importantly also for the giant HYM slope failure. To date, it is not clear, if the studied slope is fully preconditioned to fail completely in future or if it might be slowly deforming and creeping at present. We detected widespread methane seepage on the adjacent shallow shelf areas not sealed by gas hydrates.

scholarly journals Bathymetric and Seismic Data, Heat Flow Data, and Age Constraints of Le Gouic Seamount, Northeastern Atlantic

2021 ◽  
Vol 8 ◽  
Author(s):  
Andreas Klügel ◽  
Miriam Römer ◽  
Paul Wintersteller ◽  
Kai-Frederik Lenz ◽  
Sebastian Krastel ◽  
...  
Keyword(s):  
Heat Flow ◽  
Seismic Data ◽  
Flow Data ◽  
Age Constraints ◽  
Northeastern Atlantic

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.

Introduction: geological and geophysical studies in the Trans-European Suture Zone

1997 ◽  
Vol 134 (5) ◽  
pp. 585-590 ◽  
Author(s):  
T. C. PHARAOH ◽  
R. W. ENGLAND ◽  
J. VERNIERS ◽  
A. ŻELAŹNIEWICZ
Keyword(s):  
Heat Flow ◽  
Seismic Data ◽  
Lithospheric Mantle ◽  
Western Europe ◽  
Velocity Structure ◽  
Sedimentary Basins ◽  
Suture Zone ◽  
Crystalline Basement ◽  
East European ◽  
Thick Crust

The Trans-European Suture Zone (TESZ) is the boundary between ancient Precambrian lithosphere of the East European Craton (EEC) and the younger lithosphere beneath the latest Neoproterozoic–Palaeozoic mobile belts of western Europe. The former is characterized by a thick crust (c. 45 km), low heat flow and a tectono-thermal age of about 3000 to 800 Ma, the latter by a thinner crust (c. 30 km), higher heat flow and a tectonothermal age of 560 to 290 Ma. These contrasting types of crust were juxtaposed during the Caledonian and Variscan orogenic episodes. The crystalline basement of the TESZ is largely concealed by sedimentary basins controlled by the reactivation of structures within the suture zone during Permian–Mesozoic extension and Cenozoic inversion. The pre-Permian evolution of the craton and the mobile belts, and the location of the sutures, is inferred from isolated outcrops, hundreds of boreholes and geophysical evidence. Existing seismic data demonstrates that the TESZ is rather narrow and has an expression at all levels of the lithosphere and deep into the asthenosphere. Teleseismic studies have demonstrated that the differences in the velocity structure of the asthenospheric and lithospheric mantle across the TESZ persist to depths of c. 400 km (Zielhus & Nolet, 1994).

PROCESSING AND IMAGING OF MARINE SEISMIC DATA FROM THE JEQUITINHONHA BASIN (BAHIA, BRAZIL)

2016 ◽  
Vol 33 (3) ◽  
Author(s):  
Lourenildo W.B. Leite ◽  
J. Mann ◽  
Wildney W.S. Vieira
Keyword(s):  
Seismic Data ◽  
Sedimentary Basins ◽  
Study Results ◽  
Marine Seismic ◽  
Present Case Study

ABSTRACT. The present case study results from a consistent processing and imaging of marine seismic data from a set collected over sedimentary basins of the East Brazilian Atlantic. Our general aim is... RESUMO. O presente artigo resulta de um processamento e imageamento consistentes de dados sísmicos marinhos de levantamento realizado em bacias sedimentares do Atlântico do Nordeste...

Potentially Large Subsurface Gas Hydrate Bodies in the Mexican Ridges, Southwestern Gulf of Mexico

2021 ◽  
pp. 1-29
Author(s):  
Papia Nandi ◽  
Patrick Fulton ◽  
James Dale
Keyword(s):  
Gulf Of Mexico ◽  
Gas Hydrate ◽  
Seismic Data ◽  
Poor Quality ◽  
Reflection Point ◽  
Seismic Reflection Data ◽  
Reflection Data ◽  
High Impedance ◽  
Acoustic Velocities ◽  
Seismic Images

As rising ocean temperatures can destabilize gas hydrate, identifying and characterizing large shallow hydrate bodies is increasingly important in order to understand their hazard potential. In the southwestern Gulf of Mexico, reanalysis of 3D seismic reflection data reveals evidence for the presence of six potentially large gas hydrate bodies located at shallow depths below the seafloor. We originally interpreted these bodies as salt, as they share common visual characteristics on seismic data with shallow allochthonous salt bodies, including high-impedance boundaries and homogenous interiors with very little acoustic reflectivity. However, when seismic images are constructed using acoustic velocities associated with salt, the resulting images were of poor quality containing excessive moveout in common reflection point (CRP) offset image gathers. Further investigation reveals that using lower-valued acoustic velocities results in higher quality images with little or no moveout. We believe that these lower acoustic values are representative of gas hydrate and not of salt. Directly underneath these bodies lies a zone of poor reflectivity, which is both typical and expected under hydrate. Observations of gas in a nearby well, other indicators of hydrate in the vicinity, and regional geologic context, all support the interpretation that these large bodies are composed of hydrate. The total equivalent volume of gas within these bodies is estimated to potentially be as large as 1.5 gigatons or 10.5 TCF, considering uncertainty for estimates of porosity and saturation, comparable to the entire proven natural gas reserves of Trinidad and Tobago in 2019.

scholarly journals Improved Interpretation of Deep Seismic Reflection Data in Areas of Complex Geology Through Integration With Passive Seismic Data Sets

2018 ◽  
Vol 123 (12) ◽  
pp. 10,810-10,830
Author(s):  
Michael Dentith ◽  
Huaiyu Yuan ◽  
Ruth Elaine Murdie ◽  
Perla Pina-Varas ◽  
Simon P. Johnson ◽  
...  
Keyword(s):  
Seismic Data ◽  
Seismic Reflection ◽  
Data Sets ◽  
Seismic Reflection Data ◽  
Deep Seismic Reflection ◽  
Reflection Data ◽  
Passive Seismic ◽  
Complex Geology
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