Cenozoic gravity tectonics in the northern Gulf of Mexico induced by crustal extension. A new interpretation of multichannel seismic data

2008 ◽  
Vol 179 (2) ◽  
pp. 117-128 ◽  
Author(s):  
Claude Rangin ◽  
Xavier Le Pichon ◽  
Nicolas Flotté ◽  
Laurent Husson
Keyword(s):  
Gulf Of Mexico ◽  
Seismic Data ◽  
Gravity Data ◽  
Passive Margin ◽  
Lateral Motion ◽  
Crustal Extension ◽  
High Penetration ◽  
Crustal Thinning ◽  
New Interpretation ◽  
Multichannel Seismic Data

Abstract The Gulf of Mexico margin in Texas is one of the most impressive examples of starved passive margin gravity collapse systems. Growth faults developed upslope and are compensated down slope by toe folding and thrusting. On the basis of new multi-channel seismic data with high penetration (down to 11 s-twtt) we present evidences for deep crustal extension and rifting that have enhanced superficial sliding. This hypothesis is supported by a significant heat flow anomaly and crustal thinning independently deduced from gravity data. This Cenozoic rifting episode is tectonically linked to left lateral motion along the Rio Bravo fault, a reactivated branch of the Texas lineament.

scholarly journals Crustal structure, tectonic subsidence and lithospheric stretching of the princess Elizabeth trough basin, East Antarctica

2019 ◽  
pp. 92-104
Author(s):  
G. L. Leitchenkov ◽  
Yu. I. Galushkin ◽  
Yu. B. Guseva ◽  
V. V. Gandyukhin ◽  
E. P. Dubinin
Keyword(s):  
Crustal Structure ◽  
Seismic Data ◽  
Thermal Evolution ◽  
Gravity Data ◽  
Seismic Stratigraphy ◽  
Passive Margin ◽  
Tectonic Subsidence ◽  
Crustal Extension ◽  
Stretching Factor ◽  
Multichannel Seismic Data

Abstract This paper considers crustal structure, seismic stratigraphy, thermal evolution and lithospheric stretching of the deep-water basin located on the East Antarctic passive margin in the Princess Elizabeth Trough. Seven of the Middle Jurassic to Quaternary seismic sequences was identified based on interpretation of multichannel seismic data. The information about seismic stratigraphy and crustal thickness (calculated from gravity data) along the section crossing the Princess Elizabeth Trough was used for numerical modeling of the thermal regime of the lithosphere, tectonic subsidence of the crystalline basement and lithospheric stretching. Modeling shows that calculated tectonic subsidence is possible only under the assumption of crustal extension before the deposition (during the crustal doming at the early rift phase). Maximum stretching factor in the basin ranges from 1.1 to 2.0 for the period which preceded the deposition and 2.8 for the period of the rift-related deposition.

scholarly journals A fresh look at Gulf of Mexico tectonics: Testing rotations and breakup mechanisms from the perspective of seismically constrained potential-fields modeling and plate kinematics

2020 ◽  
Vol 8 (4) ◽  
pp. SS31-SS45
Author(s):  
Daniel Minguez ◽  
E. Gerald Hensel ◽  
Elizabeth A. E. Johnson
Keyword(s):  
Gulf Of Mexico ◽  
Seismic Data ◽  
Gravity Data ◽  
Seafloor Spreading ◽  
Plate Motion ◽  
Rock Properties ◽  
Satellite Gravity ◽  
Spreading Model ◽  
Breakup Mechanism ◽  
Mantle Exhumation

Interpretation of recent, high-quality seismic data in the Gulf of Mexico (GOM) has led to competing hypotheses regarding the basin’s rift to drift transition. Some studies suggest a fault-controlled mechanism that ultimately results in mantle exhumation prior to seafloor spreading. Others suggest voluminous magmatic intrusion accommodates the terminal extension phase and results in the extrusion of volcanic seaward dipping reflectors (SDRs). Whereas it has been generally accepted that the plate motions between the rift and drift phases of the GOM are nearly perpendicular to each other, it has not been greatly discussed if the breakup mechanism plays a role in accommodating the transition in plate motion. We have developed a plate kinematic and crustal architecture hypothesis to address the transition from rift to drift in the GOM. We support the proposition of a fault-controlled breakup mechanism, in which slip on a detachment between the crust and mantle may have exhumed the mantle. However, we stress that this mechanism is not exclusive of synrift magmatism, though it does imply that SDRs observed in the GOM are not in this case indicative of a volcanic massif separating attenuated continental and normal oceanic crust. We support our hypothesis through a geometrically realistic 2D potential field model, which includes a magnetic seafloor spreading model constrained by recent published seismic data and analog rock properties. The 2D model suggests that magnetic anomalies near the continent-ocean transition may be related to removal of the lower continental crust during a phase of hyperextension prior to breakup, ending in mantle exhumation. The kinematics of breakup, derived from recent satellite gravity data and constrained by our spreading model and the global plate circuit, suggests that this phase of hyperextension accommodated the change in plate motion direction and a diachronous breakup across the GOM.

A seismic refraction and reflexion study of the continent-ocean transition beneath the north Biscay margin

1982 ◽  
Vol 305 (1489) ◽  
pp. 5-25 ◽  
Keyword(s):  
Seismic Data ◽  
Seismic Refraction ◽  
Passive Margin ◽  
Ocean Crust ◽  
Northern Margin ◽  
The North ◽  
Seismic Refraction Data ◽  
Processing Techniques ◽  
Multichannel Seismic Data ◽  
Refraction Data

The structure of the northern margin of the Bay of Biscay consists of a series of tilted and rotated blocks bounded by prominent listric faults whose polarity is consistently down toward the continent-ocean boundary. These blocks formed by rifting in late Jurassic - early Cretaceous time and are now thinly covered by post-rift sediments of Aptian to Recent age. Seismic refraction profiles were occupied on the shelf, on either side of and across the continent-ocean transition to the shelf, using P ubs and O bs with explosives and a 4 x 1000 in 3 (4 x 16400 cm 3 ) airgun array. Two-ship expanding spread multichannel (48-trace) seismic reflexion profiles and 30 km fixed offset reflexion profiles were located along the seismic refraction profiles on either side of the transition. A two-ship 30 km fixed offset multichannel profile was located across the transition as well as a 5 km fixed offset multichannel profile extending from the ocean crust to the shelf. Conventional 48-trace single ship multichannel profiles were located along all the refraction and two-ship reflexion lines. Interpretation of the refraction profiles has been made by using ray tracing as well as synthetic seismograms. Conventional seismic processing techniques have been used to prepare the two-ship multichannel seismic data for interpretation. The survey is believed to be the first attempt to apply two-ship multichannel seismic data to the study of the change in crustal structure of a rifted passive margin from the shelf to the ocean crust. The results from the experiment led to the identification of a zone of transition between continental and oceanic crust about 8 km wide. The seismic refraction data show progressive thinning of the continental crust from 33 km to about 5 km close to the transition zone. However, extension values calculated in the upper crust from the rotation of fault blocks are much less (1.1—1.4) and suggest that the majority of the thinning is achieved by extensive attenuation of the lower crust.

A possible new hydrocarbon play, offshore central West Greenland

1998 ◽  
pp. 28-30
Author(s):  
Nina Skaarup ◽  
James A. Chalmers
Keyword(s):  
Seismic Data ◽  
Mineral Resources ◽  
Source Rocks ◽  
Bright Spot ◽  
Offshore Area ◽  
West Greenland ◽  
The Government ◽  
Structural Closure ◽  
Multichannel Seismic Data ◽  
Seismic Lines

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Skaarup, N., & Chalmers, J. A. (1998). A possible new hydrocarbon play, offshore central West Greenland. Geology of Greenland Survey Bulletin, 180, 28-30. https://doi.org/10.34194/ggub.v180.5082 _______________ The discovery of extensive seeps of crude oil onshore central West Greenland (Christiansen et al. 1992, 1994, 1995, 1996, 1997, 1998, this volume; Christiansen 1993) means that the central West Greenland area is now prospective for hydrocarbons in its own right. Analysis of the oils (Bojesen-Koefoed et al. in press) shows that their source rocks are probably nearby and, because the oils are found within the Lower Tertiary basalts, the source rocks must be below the basalts. It is therefore possible that in the offshore area oil could have migrated through the basalts and be trapped in overlying sediments. In the offshore area to the west of Disko and Nuussuaq (Fig. 1), Whittaker (1995, 1996) interpreted a few multichannel seismic lines acquired in 1990, together with some seismic data acquired by industry in the 1970s. He described a number of large rotated fault-blocks containing structural closures at top basalt level that could indicate leads capable of trapping hydrocarbons. In order to investigate Whittaker’s (1995, 1996) interpretation, in 1995 the Geological Survey of Greenland acquired 1960 km new multichannel seismic data (Fig. 1) using funds provided by the Government of Greenland, Minerals Office (now Bureau of Minerals and Petroleum) and the Danish State through the Mineral Resources Administration for Greenland. The data were acquired using the Danish Naval vessel Thetis which had been adapted to accommodate seismic equipment. The data acquired in 1995 have been integrated with the older data and an interpretation has been carried out of the structure of the top basalt reflection. This work shows a fault pattern in general agreement with that of Whittaker (1995, 1996), although there are differences in detail. In particular the largest structural closure reported by Whittaker (1995) has not been confirmed. Furthermore, one of Whittaker’s (1995) smaller leads seems to be larger than he had interpreted and may be associated with a DHI (direct hydrocarbon indicator) in the form of a ‘bright spot’.

scholarly journals Comparing global tomography-derived and gravity-based upper mantle density models

2020 ◽  
Vol 221 (3) ◽  
pp. 1542-1554 ◽  
Author(s):  
B C Root
Keyword(s):  
Seismic Tomography ◽  
Upper Mantle ◽  
Seismic Data ◽  
Gravity Data ◽  
Heterogeneous Data ◽  
Clear Correlation ◽  
Data Sets ◽  
Satellite Gravity ◽  
Similar Density ◽  
Similar Peak

SUMMARY Current seismic tomography models show a complex environment underneath the crust, corroborated by high-precision satellite gravity observations. Both data sets are used to independently explore the density structure of the upper mantle. However, combining these two data sets proves to be challenging. The gravity-data has an inherent insensitivity in the radial direction and seismic tomography has a heterogeneous data acquisition, resulting in smoothed tomography models with de-correlation between different models for the mid-to-small wavelength features. Therefore, this study aims to assess and quantify the effect of regularization on a seismic tomography model by exploiting the high lateral sensitivity of gravity data. Seismic tomography models, SL2013sv, SAVANI, SMEAN2 and S40RTS are compared to a gravity-based density model of the upper mantle. In order to obtain similar density solutions compared to the seismic-derived models, the gravity-based model needs to be smoothed with a Gaussian filter. Different smoothening characteristics are observed for the variety of seismic tomography models, relating to the regularization approach in the inversions. Various S40RTS models with similar seismic data but different regularization settings show that the smoothening effect is stronger with increasing regularization. The type of regularization has a dominant effect on the final tomography solution. To reduce the effect of regularization on the tomography models, an enhancement procedure is proposed. This enhancement should be performed within the spectral domain of the actual resolution of the seismic tomography model. The enhanced seismic tomography models show improved spatial correlation with each other and with the gravity-based model. The variation of the density anomalies have similar peak-to-peak magnitudes and clear correlation to geological structures. The resolvement of the spectral misalignment between tomographic models and gravity-based solutions is the first step in the improvement of multidata inversion studies of the upper mantle and benefit from the advantages in both data sets.

Acquisition of 3D, 4C seismic data for offshore Gulf of Mexico time lapse studies

1998 ◽  
Author(s):  
Dan Ebrom ◽  
Paul Krail ◽  
Larry Scott
Keyword(s):  
Gulf Of Mexico ◽  
Seismic Data ◽  
Time Lapse
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