Crustal structure of Mesozoic rifting in the northeastern Gulf of Mexico from integration of seismic and potential fields data

We have investigated the crustal structure of a 400 km wide zone of thinned continental crust in the northeastern Gulf of Mexico (GOM) using gravity and magnetic modeling along two deeply penetrated seismic transects. Using this approach, we identify two zones of prominent, southward-dipping reflectors associated with 7–10 km thick, dense, and highly magnetic material. Previous workers have interpreted the zones as either coarse clastic redbeds of Mesozoic age that are tilted within half-grabens or seaward-dipping reflectors of magmatic origin. Both seismic reflection lines reveal a 10 km thick and 67 km wide northern zone of high density near the Florida coastline beneath the Apalachicola rift (AR). The southern zone of high density occurs 70 km to the south in the deepwater central GOM along the northern flank of the marginal rift, a 48 km wide, southeast-trending structure of inferred Late Jurassic age that is filled by 3 km of low-density and low-magnetic susceptibility sediments including complexly deformed salt deposits. We propose that these two subparallel rifts and their associated magmatic belts formed in the following sequence: (1) AR formed during Triassic-early Jurassic (210–163 Ma) phase 1 of diffuse continental stretching and was partially infilled on its northern edge by southward-dipping volcanic flows; and (2) the similarly southward-dipping southern magmatic zone formed adjacent to the marginal rift during the early phase 2 of late Jurassic (161–153 Ma) rifting of the GOM continental extension; this southern area of SDR formation immediately preceded the formation of the adjacent oceanic crust that separated the rift-related evaporates into the northern and southern GOM. Our integrated approach combining 2D seismic, gravity, and magnetic data sets results in a more confident delineation of these deep crustal features than from seismic data alone.

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An Integrated Approach to Well Logging: The Case of the Bazhenov Formation

10.2118/208545-ms ◽

2021 ◽

Author(s):

Dmitry Mikhailovich Lazutkin ◽

Oleg Vladimirovich Bukov ◽

Denis Vagizovich Kashapov ◽

Albina Viktorovna Drobot ◽

Maria Alexandrovna Stepanova ◽

...

Keyword(s):

Gulf Of Mexico ◽

Integrated Approach ◽

Donets Basin ◽

Lower Carboniferous ◽

Upper Carboniferous ◽

Salt Domes ◽

Axial Part ◽

Gravity And Magnetic ◽

Play Elements ◽

Hydrocarbon Reserves

Abstract New geological structures – displaced blocks of salt diapirs’ overburden – were identified in the axial part of the Dnieper-Donets basin (DDB) beside one of the largest salt domes due to modern high-precision gravity and magnetic surveys and their joint 3D inversion with seismic and well log data. Superposition of gravity lineaments and wells penetrating Middle and Lower Carboniferous below Permian and Upper Carboniferous sediments in proximity to salt allowed to propose halokinetic model salt overburden displacement, assuming Upper Carboniferous reactivation. Analogy with rafts and carapaces of the Gulf of Mexico is considered in terms of magnitude of salt-induced deformations. Density of Carboniferous rocks within the displaced flaps evidence a high probability of hydrocarbon saturation. Possible traps include uplifted parts of the overturned flaps, abutting Upper Carboniferous reservoirs, and underlying Carboniferous sequence. Play elements are analyzed using analogues from the Dnieper-Donets basin and the Gulf of Mexico. Hydrocarbon reserves of the overturned flaps within the study area are estimated to exceed Q50 (Р50) = 150 million cubic meters of oil equivalent.

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Determination of Tectonic and Crustal Structure of the Eastern Pontide Orogenic Belt (NE Turkey) Using Gravity and Magnetic Data

Pure and Applied Geophysics ◽

10.1007/s00024-009-0529-7 ◽

2009 ◽

Vol 166 (12) ◽

pp. 1987-2006 ◽

Cited By ~ 24

Author(s):

Nafiz Maden ◽

Kenan Gelisli ◽

Yener Eyuboglu ◽

Osman Bektas

Keyword(s):

Crustal Structure ◽

Orogenic Belt ◽

Magnetic Data ◽

Gravity And Magnetic ◽

Gravity And Magnetic Data

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Gravity and Magnetic Methods

Continental Shelf Limits ◽

10.1093/oso/9780195117820.003.0018 ◽

2000 ◽

Author(s):

Richard M. Carruthers ◽

John D. Cornwell

Keyword(s):

Large Scale ◽

Gravity Data ◽

Integrated Approach ◽

Rock Properties ◽

Magnetic Data ◽

Satellite Gravity ◽

Fully Integrated ◽

Continental Shelves ◽

Gravity And Magnetic ◽

Gravity And Magnetic Data

Lateral variations in the density and magnetization of the rocks within the crust give rise to "anomalies" in the Earth's gravity and magnetic fields. These anomalies can be measured and interpreted in terms of the geology both in a qualitative sense, by mapping out trends and changes in anomaly style, and quantitatively, by creating models of the subsurface which reproduce the observed fields. Such interpretations are generally less definitive in themselves than the results from seismic surveys (see chapter 12), but the data are widely available and can provide information in areas where other methods are ineffective or have not been applied. As the different geophysical techniques respond to specific rock properties such as density, magnetization, and acoustic velocity, the results are complementary, and a fully integrated approach to data collection and interpretation is generally more effective than the sum of its parts assessed on an individual basis. Gravity and magnetic data have been acquired, at least to a reconnaissance scale, over most of the world. In particular, the release into the public domain of satellite altimetry information (combined with improved methods of data processing) means that there is gravity coverage to a similar standard for most of the offshore region to within about 50 km of the coast. Magnetic anomalies recorded from satellites provide global coverage, but the high altitude of the observations means that only large-scale features extending over many 10s of kilometers are delineated. Reconnaissance aeromagnetic surveys with flight lines 10-20 km apart provide a lateral anomaly resolution similar to that of the satellite gravity data. Oceanographic surveys undertaken by a variety of academic and research institutions are another valuable source of data in remote regions offshore which supplement and extend the more detailed coverage obtained over the continental shelves, for example, by oil companies in areas of hydrocarbon interest. Surveys over land vary widely in terms of acquisition parameters and quality, but some form of national compilation is available from many countries. A number of possible applications of the potential field (i.e., gravity and magnetic) data follow from the terms set out by UNCLOS. Paragraph 4(b) of article 76 states, "In the absence of evidence to the contrary, the foot of the continental slope is to be determined as the point of maximum change in the gradient at its base" (italics added).

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Upper crustal structure of Deception Island area (Bransfield Strait, Antarctica) from gravity and magnetic modelling

Antarctic Science ◽

10.1017/s0954102005002622 ◽

2005 ◽

Vol 17 (2) ◽

pp. 213-224 ◽

Cited By ~ 27

Author(s):

A. MUÑOZ-MARTÍN ◽

M. CATALÁN ◽

J. MARTÍN-DÁVILA ◽

A. CARBÓ

Keyword(s):

Crustal Structure ◽

Gravity Data ◽

Bouguer Anomaly ◽

Active Volcano ◽

Magnetic Data ◽

Deception Island ◽

Intrusive Body ◽

The South ◽

Bransfield Strait ◽

Gravity And Magnetic

Deception Island is a young, active volcano located in the south-western part of Bransfield Strait, between the Antarctic Peninsula and the South Shetland archipelago. New gravity and magnetic data, from a marine geophysical cruise (DECVOL-99), were analysed. Forty-eight survey lines were processed and mapped around Deception Island to obtain Bouguer and magnetic anomaly maps. These maps show well- defined groups of gravity and magnetic anomalies, as well as their gradients. To constrain the upper crustal structure, we have performed 2+1/2D forward modelling on three profiles perpendicular to the main anomalies of the area, and taking into account previously published seismic information. From the gravity and magnetic models, two types of crust were identified. These were interpreted as continental crust (located north of Deception Island) and more basic crust (south of Deception Island). The transition between these crustal types is evident in the Bouguer anomaly map as a high gradient area trending NE–SW. Both magnetic and gravity data show a wide minimum at the eastern part of Deception Island, which suggests a very low bulk susceptibility and low density intrusive body. With historical recorded eruptions and thermal and fumarolic fields, we interpret this anomaly as a partially melted intrusive body. Its top has been estimated to be at 1.7 km depth using Euler deconvolution techniques.

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