Crustal architecture of the northwestern and central Gulf of Mexico from integrated geophysical analysis

The tectonic history of the Gulf of Mexico (GOM) is a subject for ongoing debate. The nature of the crust in the northwestern and central parts of the basin remains poorly understood. Joined interpretation of two 2D seismic cross sections — GUMBO1 and GUMBO2 — with potential fields (gravity and magnetics) constrained with available well data allows testing various hypotheses about the subsurface structures and crustal architecture in the study area. In the northwestern GOM, two contradicting hypotheses about the nature of the crust were tested — exhumed mantle versus a thinned and intruded continental crust resulted from magma-rich rifting. The nature of the crust was also investigated in the central GOM, where the disagreement in the location of the ocean-continent boundary (OCB) from various published tectonic models reaches 140 km (87 mi). The results suggest that the crust in the study area is stretched continental with multiple magmatic additions represented by dense and highly magnetic bodies with fast seismic velocities, presumably introduced during the magma-assisted rifting of the GOM. The contact between oceanic and continental domains, i.e., the OCB, is interpreted to be near the Sigsbee Escarpment for both modeled lines. The analysis does not support the presence of thick presalt sediments in the study area. This result questions the currently accepted tectonic reconstructions of the GOM as thick presalt deposits are imaged confidently by various seismic surveys along the western Yucatan margin, which is believed to be a conjugate for the study area. This apparent mismatch in distribution of the presalt sediments requires further investigation.

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FREE‐AIR GRAVITY ANOMALY MAP OF THE GULF OF MEXICO AND ITS TECTONIC IMPLICATIONS, 1963 EDITION

Geophysics ◽

10.1190/1.1439522 ◽

1965 ◽

Vol 30 (1) ◽

pp. 102-110 ◽

Cited By ~ 13

Author(s):

Peter Dehlinger ◽

B. R. Jones

Keyword(s):

Gulf Of Mexico ◽

Cross Sections ◽

Seismic Refraction ◽

Seismic Velocities ◽

Surface Ship ◽

Free Air ◽

Anomaly Map ◽

Free Air Gravity ◽

Free Air Anomaly ◽

Mohorovičić Discontinuity

As part of a continuing program, Texas A. and M. University has been making a surface‐ship gravity survey of the Gulf of Mexico. The 1963 free‐air anomaly map of the Gulf is the second in a series of maps resulting from these investigations; it includes not only a larger area than the first map, but also measurements having considerably higher accuracies. The present map indicates, as the first one suggested, that the Gulf of Mexico is essentially in isostatic equilibrium but contains local mass anomalies. Two cross sections of crustal layers were constructed which are consistent with the gravity observations and published seismic‐refraction results. One section extends from Galveston, Texas, to the Yucatan Peninsula, and the other from the Sigsbee Deep to Florida. Both sections consist of four to six layers, in which layer densities were assumed to be uniform laterally and the density below the Mohorovičić discontinuity constant. Densities of the layers were converted from seismic velocities using the Drake and Nafe curves. A free‐air anomaly profile across the Cayman Trench is included.

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Predrill pore‐pressure prediction using seismic data

Geophysics ◽

10.1190/1.1500391 ◽

2002 ◽

Vol 67 (4) ◽

pp. 1286-1292 ◽

Cited By ~ 89

Author(s):

C. M. Sayers ◽

G. M. Johnson ◽

G. Denyer

Keyword(s):

Velocity Field ◽

Gulf Of Mexico ◽

Pore Pressure ◽

Seismic Data ◽

Seismic Velocities ◽

Pressure Data ◽

Pore Pressure Prediction ◽

Well Data ◽

Interval Velocities ◽

Reflection Tomography

1A predrill estimate of pore pressure can be obtained from seismic velocities using a velocity‐to–pore‐pressure transform, but the seismic velocities need to be derived using methods having sufficient resolution for well planning purposes. For a deepwater Gulf of Mexico example, significant differences are found between the velocity field obtained using reflection tomography and that obtained using a conventional method based on the Dix equation. These lead to significant differences in the predicted pore pressure. Parameters in the velocity‐to–pore‐pressure transform are estimated using seismic interval velocities and pressure data from nearby calibration wells. The uncertainty in the pore pressure prediction is analyzed by examining the spread in the predicted pore pressure obtained using parameter combinations which sample the region of parameter space consistent with the available well data. If calibration wells are not available, the ideas proposed in this paper can be used with measurements made while drilling to predict pore pressure ahead of the bit based on seismic velocities.

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THE GEOPHYSICAL HISTORY OF THE CAYUGA FIELD, ANDERSON COUNTY, TEXAS

Geophysics ◽

10.1190/1.1445081 ◽

1944 ◽

Vol 9 (3) ◽

pp. 299-313

Author(s):

H. B. Peacock

Keyword(s):

Cross Sections ◽

Correlation Method ◽

Geological Structure ◽

History Of ◽

Well Data

Original seismic maps based on the correlation method of reflection shooting are presented, together with a geological structure map. Cross sections show a comparison of the seismic and the well data. Results of a gravity‐meter survey are also shown.

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INCORPORATION OF NEW DATA TO REFINE THE TECTONIC HISTORY OF THE GULF OF MEXICO 230 MA - 180 MA

10.1130/abs/2019se-327156 ◽

2019 ◽

Author(s):

Hannah B Hartley ◽

◽

Erin K. Beutel ◽

Irina Filina ◽

Mei Liu

Keyword(s):

Gulf Of Mexico ◽

Tectonic History ◽

History Of

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Crustal Deformations and Geomorphological Units of Arabian Plate Foreland Region, North and Northeast of Iraq

Journal of Southwest Jiaotong University ◽

10.35741/issn.0258-2724.54.5.1 ◽

2019 ◽

Vol 54 (5) ◽

Author(s):

Ahmed Abbas Hasan ◽

Mohammed Lateef Hussien ◽

Linaz Anis Fadhil ◽

Mariam Isam Hasan ◽

Cristina Dallos Mosquera

Keyword(s):

Cross Sections ◽

Fault System ◽

Arabian Plate ◽

Alluvial Fans ◽

Zagros Mountains ◽

Flood Plains ◽

Tectonic History ◽

Geomorphological Units ◽

History Of ◽

Geologic Factor

The crustal shortening in the foreland of Arabian Plate (the Taurus and Zagros Mountains system) in N and NE of Iraq is accommodated in two principal ways: folding and thrusting. The fold and thrust patterns have evolved as an expression of shortening which was approximately NE-SW directed and subparallel to the bedding. In this area, observations of deformations along different cross sections were made using balancing cross sections for the estimation of the total shortening on five cross sections. The authors showed that shortening deformations were irregular and non-identical, which date back to the same age and the same location. This suggests that defects in this region are not homogeneous due to irregular bottom of the sedimentary basin, fault system and the form of the collision zone between the Arabian Plate and Iranian Plate or between the Arabian Plate and the Anatolian Plate. According to these magnitudes, the foreland region of Arabian Plate is affected by inhomogeneous deformations that are related rather to where these structures were developed, than to when they were formed. This study demonstrates the significant influence of geologic factor (especially structure) in forming and developing geomorphological features with a structural origin. These features are associated with tectonic history of the study area, such as units of structural origin. Another features related to the denudational factors, like glacis and badland, in addition to the features of fluvial origin which are alluvial fans, terraces and flood plains.

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American Contributions to the Geological Mapping of Hokkaido, Late Nineteenth Century

Earth Sciences History ◽

10.17704/eshi.30.1.6w834065q2671225 ◽

2011 ◽

Vol 30 (1) ◽

pp. 39-57 ◽

Cited By ~ 1

Author(s):

Kenneth Aalto

Keyword(s):

Cross Sections ◽

Mineral Resources ◽

Geological Mapping ◽

Late Nineteenth Century ◽

Mining Operations ◽

Meiji Restoration ◽

Tectonic History ◽

History Of ◽

Geologic Map ◽

Mine Development

During 1861-1862 Raphael Pumpelly (1838-1923) was engaged by the Japanese Government (the Tokugawa Shogunate) to review mineral resources and advise on mining operations. Political pressures against the Government's employ of foreigners resulted in his investigation being confined to southern Hokkaido and, at the end of 1862, led to the termination of his contract. Pumpelly completed a geological sketch map with structural cross-sections, provided formation descriptions, interpretations of landforms, suggestions for mine development, and interpretations of the tectonic history of the island. Remarking on the general parallelism of Asian mountain ranges, major valleys, coastlines and the Japanese islands, Pumpelly envisioned a NE-SW-trending system of tectonic elevation and depression that governed the geomorphic configuration of the Northern Hemisphere worldwide. In 1878, under the new leadership of the Emperor following the Meiji Restoration, foreign specialists were welcomed to Japan in order to modernize government, science, and industry. Benjamin Smith Lyman (1835-1920) and Henry Smith Munroe (1850-1933) undertook geologic studies of Hokkaido, focusing on mineral resources, and produced a regional stratigraphy, structural synthesis and geologic map for the entire island. Their work, published by the development agency for Hokkaido (the Kaitakushi), served as a foundation for further studies by Japanese researchers, many of whom began as assistants to Lyman and Munroe.

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