Three‐dimensional gravity modeling in Newark Valley, Nevada: A structural interpretation from gravity data

1986 ◽  
Author(s):  
William C. Pearson
Geophysics ◽  
1987 ◽  
Vol 52 (9) ◽  
pp. 1265-1278 ◽  
Author(s):  
Mark E. Ander ◽  
Stephen P. Huestis

The interpretation of gravity anomaly data suffers from a fundamental nonuniqueness, even when the solution set is bounded by physical or geologic constraints. Therefore, constructing a single solution that fits or approximately fits the data is of limited value. Consequently, much effort has been applied in recent years to developing inverse techniques for rigorous deduction of properties common to all possible solutions. To this end, Parker developed the theory of an ideal body, which characterizes the extremal solution with the smallest possible maximum density. Gravity ideal‐body analysis is an excellent reconaissance exploration tool because it is especially well suited for handling sparse data contaminated with noise, for finding useful, rigorous bounds on the infinite solution set, and for predicting accurately what data need to be collected in order to tighten those bounds. We present a practical three‐ dimensional gravity ideal‐body computer code, IDB, that can optimize a mesh with over [Formula: see text] cells when used on a CRAY computer. Using actual gravity data, we use IDB to produce ideal‐body tradeoff curves that bound the solution set and show how to restrict the bound on the solution further by applying geologic and geophysical data to the tradeoff curves. As an example, we compare two‐dimensional and three‐dimensional ideal‐body results from a study of a positive anomaly associated with the Lucero uplift located on the western flank of the Rio Grande rift in New Mexico.


2017 ◽  
Vol 54 (8) ◽  
pp. 869-882 ◽  
Author(s):  
Régis Roy ◽  
Antonio Benedicto ◽  
Alexis Grare ◽  
Mickaël Béhaegel ◽  
Yoann Richard ◽  
...  

In unconformity-related uranium deposits, mineralization is associated with hydrothermal clay-rich alteration haloes that decrease the density of the host rock. In the Kiggavik uranium project, located in the eastern Thelon Basin, Nunavut (Canada), basement-hosted shallow deposits were discovered by drilling geophysical anomalies in the 1970s. In 2014, gravity data were inverted for the first time using the Geosoft VOXI Earth ModellingTM system to generate three-dimensional (3D) models to assist exploration in the Contact prospect, the most recent discovery at Kiggavik. A 3D unconstrained inversion model was calculated before drilling, and a model constrained by petrophysical data was computed after drilling. The unconstrained inversion provided a first approximation of the geometry and depth of a low-density body and helped to collar the discovery holes of the Contact mineralization. The constrained inversion was computed using density values measured on 315 core samples collected from 21 drill holes completed between 2014 and 2015. The constrained modelling highlights three shallower and smaller low-density bodies that match the geological interpretation and refines the footprint of the gravity anomalies in relation to the current understanding of the deposit. The 3D inversion of gravity data is a valuable tool to guide geologists in exploration of shallow basement-hosted uranium deposits associated with alteration haloes and to assess the deposit gravity geometry.


1982 ◽  
Author(s):  
H.‐J. Goetze ◽  
F. Keller ◽  
B. Lahmeyer ◽  
O. Rosenbach

2013 ◽  
Vol 65 (9) ◽  
pp. 973-983 ◽  
Author(s):  
José A. Batista-Rodríguez ◽  
Marco A. Pérez-Flores ◽  
Jaime Urrutia-Fucugauchi

1990 ◽  
Vol 16 (3) ◽  
pp. 277-287 ◽  
Author(s):  
I.V. Radhakrishna Murthy ◽  
P. Rama Rao ◽  
S. Jagannadha Rao

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