Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications
Typescript (photocopy). A free-air gravity anomaly map of the North Atlantic Ocean has been constructed at a 10 mgal contour interval utilizing all available surface ship and pendulum gravity measurements. The map shows values more positive to the north of ~32°N than to the south and values more neg...
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fttexasamuniv:oai:oaktrust.library.tamu.edu:1969.1/DISSERTATIONS-451549 2023-07-16T03:59:44+02:00 Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications Jung, Woo-Yeol Rabinowitz, Philip D. Bryant, Davis A. Carlson, Richard L. Fahlquist, Davis A. Hilde, Thomas W. C. 1985 xiv, 166 leaves electronic application/pdf reformatted digital https://hdl.handle.net/1969.1/DISSERTATIONS-451549 eng eng Texas A&M University. Libraries https://hdl.handle.net/1969.1/DISSERTATIONS-451549 15708328 This thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use. http://rightsstatements.org/vocab/InC/1.0/ Gravity anomalies Marine geophysics Major oceanography 1985 Dissertation J95 North Atlantic Ocean Thesis dissertations text 1985 fttexasamuniv 2023-06-27T22:52:15Z Typescript (photocopy). A free-air gravity anomaly map of the North Atlantic Ocean has been constructed at a 10 mgal contour interval utilizing all available surface ship and pendulum gravity measurements. The map shows values more positive to the north of ~32°N than to the south and values more negative in the western North Atlantic Ocean basin than in the eastern basin. The Mid-Atlantic Ridge area and topographic highs such as volcanic islands, seamounts are associated with positive values while the rift valley and fracture zone valleys are characterized by elongated negative values. The seaward edge of the continental shelf is characterized by a belt of positive free-air gravity anomalies; negative gravity values are observed just seaward of the continental slope and rise. A total of 3032 1x1° averaged free-air gravity anomalies were determined from the surface ship gravity map. A gravimetric geoid was computed from these 1x1° averaged gravity anomalies by employing Stokes' integral theorem. Comparisons were made between the 1x1° surface ship gravity and the 1x1° SEASAT altimeter derived gravity as well as the 1x1° surface ship gravimetric geoid and the 1x1° SEASAT altimeter derived geoid. The results show very good agreement in contour trends, wavelengths and amplitudes. Two types of residual geoids were computed. The first was obtained by subtracting the long wavelength features (degree 10 geoid of GEM10 standard earth model) from the 1x1° averaged SEASAT altimeter derived geoid. The second was obtained by further subtracting the geoid variations relating to the cooling of the plates. The Azores residual geoid high which centered over the Azores triple junction when only the long wavelength features were removed shifts its center east to the Azores Island after thermal effects were accounted for. This may indicate that the main axis of smaller scale (upper 600 km) convective upwellings does not lie beneath the present day spreading center but beneath the Azores Islands. Areas of extensive volcanism such ... Thesis North Atlantic Texas A&M University Digital Repository Mid-Atlantic Ridge |
institution |
Open Polar |
collection |
Texas A&M University Digital Repository |
op_collection_id |
fttexasamuniv |
language |
English |
topic |
Gravity anomalies Marine geophysics Major oceanography 1985 Dissertation J95 North Atlantic Ocean |
spellingShingle |
Gravity anomalies Marine geophysics Major oceanography 1985 Dissertation J95 North Atlantic Ocean Jung, Woo-Yeol Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications |
topic_facet |
Gravity anomalies Marine geophysics Major oceanography 1985 Dissertation J95 North Atlantic Ocean |
description |
Typescript (photocopy). A free-air gravity anomaly map of the North Atlantic Ocean has been constructed at a 10 mgal contour interval utilizing all available surface ship and pendulum gravity measurements. The map shows values more positive to the north of ~32°N than to the south and values more negative in the western North Atlantic Ocean basin than in the eastern basin. The Mid-Atlantic Ridge area and topographic highs such as volcanic islands, seamounts are associated with positive values while the rift valley and fracture zone valleys are characterized by elongated negative values. The seaward edge of the continental shelf is characterized by a belt of positive free-air gravity anomalies; negative gravity values are observed just seaward of the continental slope and rise. A total of 3032 1x1° averaged free-air gravity anomalies were determined from the surface ship gravity map. A gravimetric geoid was computed from these 1x1° averaged gravity anomalies by employing Stokes' integral theorem. Comparisons were made between the 1x1° surface ship gravity and the 1x1° SEASAT altimeter derived gravity as well as the 1x1° surface ship gravimetric geoid and the 1x1° SEASAT altimeter derived geoid. The results show very good agreement in contour trends, wavelengths and amplitudes. Two types of residual geoids were computed. The first was obtained by subtracting the long wavelength features (degree 10 geoid of GEM10 standard earth model) from the 1x1° averaged SEASAT altimeter derived geoid. The second was obtained by further subtracting the geoid variations relating to the cooling of the plates. The Azores residual geoid high which centered over the Azores triple junction when only the long wavelength features were removed shifts its center east to the Azores Island after thermal effects were accounted for. This may indicate that the main axis of smaller scale (upper 600 km) convective upwellings does not lie beneath the present day spreading center but beneath the Azores Islands. Areas of extensive volcanism such ... |
author2 |
Rabinowitz, Philip D. Bryant, Davis A. Carlson, Richard L. Fahlquist, Davis A. Hilde, Thomas W. C. |
format |
Thesis |
author |
Jung, Woo-Yeol |
author_facet |
Jung, Woo-Yeol |
author_sort |
Jung, Woo-Yeol |
title |
Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications |
title_short |
Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications |
title_full |
Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications |
title_fullStr |
Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications |
title_full_unstemmed |
Free-air gravity and geoid anomalies of the North Atlantic Ocean and their tectonic implications |
title_sort |
free-air gravity and geoid anomalies of the north atlantic ocean and their tectonic implications |
publisher |
Texas A&M University. Libraries |
publishDate |
1985 |
url |
https://hdl.handle.net/1969.1/DISSERTATIONS-451549 |
geographic |
Mid-Atlantic Ridge |
geographic_facet |
Mid-Atlantic Ridge |
genre |
North Atlantic |
genre_facet |
North Atlantic |
op_relation |
https://hdl.handle.net/1969.1/DISSERTATIONS-451549 15708328 |
op_rights |
This thesis was part of a retrospective digitization project authorized by the Texas A&M University Libraries. Copyright remains vested with the author(s). It is the user's responsibility to secure permission from the copyright holder(s) for re-use of the work beyond the provision of Fair Use. http://rightsstatements.org/vocab/InC/1.0/ |
_version_ |
1771547948618874880 |