Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 28 for “"Gravity anomaly"”.
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Round Lake Gravity Anomaly, Delta County, Michigan
Thesis (M.S.)--Michigan State University. Dept. of Geology, 1974
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Interpretation of a gravity anomaly in the Canadian Arctic, The
Includes bibliographical references.
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Geologic framework of gravity anomaly sources in the central Piedmont of Virginia
Bouguer gravity anomalies at 1870 locations on the central Piedmont of Virginia from 37° 37' N to 37° 52' N and 77° 44' W to 78° 23' W display patterns of variation produced by upper crustal density contrasts and thickening of the crust in a WNW direction. No other deep sources are evident. Upper …
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Forward modeling the gravitational field using a direct solution of Poisson's equation
Forward modeling of gravity data typically computes the vertical gravitational acceleration using either closed-form formulae, or numerical solution of Poisson's equation governing the gravity potential followed by numerical differentiation. We present a method for computing the vertical gravity …
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A high resolution gravity survey of the Lake St. Martin impact structure, Manitoba, Canada
… year, some of which may be identified through gravity anomalies. A high-resolution gravity survey of the Lake St. Martin impact structure, southern Manitoba, Canada, was conducted to further interpret the structure's gravity anomaly. Previous studies have suggested two different crater …
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Geophysical constraints on the flexural subsidence of the Denver Basin
… American craton. A ~400 mGal negative Bouguer gravity anomaly exists over the Denver Basin and Front Range Uplift, with its minimum located over the highest topography in the central part of the uplift, approximately 100 km west of the Denver Basin. This study examines three hypotheses …
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Impact induced porosity of terrestrial impact craters : a gravity study of Meteor Crater.
In this project we gathered and interpreted gravity anomaly data at Meteor Crater, and we used these data to constrain the porosity variations across Meteor Crater that were induced by the crater-forming impact event. We performed a gravity survey at the crater and merged these new data with legacy …
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Tidal gravity anomalies in southeastern North America
Tidal variations of gravity were measured at fourteen sites in southeastern North America for periods of between 40 and 199 days. These measurements were used to obtain tidal gravity anomalies that indicate the geologic effect of the earth on tidal gravity. The tidal gravity anomaly is a vector …
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Predicted and observed free-air gravity anomalies for delamination models of the formation of the Siberian Flood Basalts
… process, calculations of predicted gravity at the surface can be used to test the model. Temperature, composition, and stress output from the delamination model presented in Elkins-Tanton (2007) were used to calculate predicted gravity measurements at the surface. These predictions …
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A geologic and potential field investigation of the central Virginia Piedmont
… Richmond Triassic Basin. The crest of a major gravity anomaly, the Piedmont gravity high, is coincident with the hinge of the State Farm Antiform. In addition, this region is in the eastern portion of the Central Virginia Seismic Zone. Detailed geologic mapping and potential field modeling …
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Seismic investigation of the Matador Arch and Central Basin Platform
… beneath mafic intrusions in the upper crust. Gravity anomaly maps, known basement rock location and composition from well data, and gravity models are compared to topographic maps of the Moho and midcrustal discontinuity. Seismic signature in the lower crust and depth to the Moho suggest a …
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Geophysical models of Mount Etna, Sicily : its structural evolution and implications for slope stability
… thrust of this work. The primary work has been gravity and aeromagnetic surveys combined with 2.5-D and 3-D modelling to develop a better understanding of the sub-surface structures of the area. This work has identified several large gravity and magnetic anomalies indicating areas of contrasting …
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A geophysical investigation of a concealed granitoid beneath Lumberton, North Carolina
… granitic pluton. This hypothesis is supported by gravity data, which show a -35 mgal Bouguer gravity anomaly, and the relatively high heat flow of 63.4±5 mW/m² obtained in the drill hole, both of which are characteristic of Hercynian granitic plutons in the southeastern United States. Gravity …
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The oligo-miocene sediments of the Maltese Islands
… Malta-Ragusa Rise, an area characterised by high gravity anomaly values and a ridge-like bathymetrical profile. The Islands lie 50-80km. south of Sicily and 282km. away from the north African coastline.The sedimentary sequence is entirely composed of shallow water carbonates, dominantly marine, …
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A Geophysical Investigation Of The Northeastern Rim Of The St. Martin Impact Structure, Manitoba, Canada.
… profiling. Selected data from a previous gravity survey was used to supplement survey results. The magnetic survey was conducted using the total field G-856 Memory-Mag proton precession magnetometer which measures local or regional field strength. The seismic reflection survey was …
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A detailed gravity study over a known Devonian carbonate buildup: the Shell Golden Reef, northwestern North Dakota
<p>A detailed gravity study was conducted over the Shell Golden reef in the northwestern North Dakota portion of the Williston Basin. The Shell Golden reef has been previously interpreted to be reefal facies within the Winnipegosis Formation (Devonian) located at a depth of about 2400 meters. Based …
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Dynamic Topography of the Borborema Province, South America
… by a positive long-wavelength free-air gravity anomaly of ∼ +30 mGal, which is consistent with sub-crustal dynamic support. This inference is corroborated by the presence of positive residual depth anomalies of 100s of meters which are observed along the abutting continental margin. …
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Magmatism in southern Uruguay and the early rifting of the South Atlantic
… of basaJtic material as recognised from a large gravity anomaly. Melt production rates in southern Uruguay were low (0.01 km<sup>3</sup> yr<sup>-1</sup>) similar to the rates ca1cuIated for the waning stages of magmatism on the Serra Geral escarpment, southern Brazil. These rates are consistent …
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The Origins of Four Paterae of Malea Planum, Mars
… (Roche et al., 2000). A very strong positive gravity anomaly is centered over Amphitrites and smaller positive anomalies are associated with Peneus and Malea Paterae. A slight annular positive anomaly is associated with Pityusa. The geology of the Malea Planum Region has been influenced by …
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Crustal accretion and evolution at slow and ultra-slow spreading mid-ocean ridges
… in a similar manner as at the MAR, although gravity and seismic data indicate that the average crustal thickness is 2-4 km less at the ultra-slow spreading SWIR. A 25 Myr record on both flanks of the ridge shows that seafloor spreading has been highly asymmetric through time, with 35% faster …
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