scholarly journals Description of slides showing aeromagnetic and gravity data for regional mineral exploration in Colorado, New Mexico, and Arizona

1983 ◽  
Author(s):  
Douglas P. Klein
Keyword(s):  
New Mexico ◽  
Mineral Exploration ◽  
Gravity Data

scholarly journals Three-Dimensional Regularized Focusing Migration: A Case Study from the Yucheng Mining Area, Shandong, China

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 471
Author(s):  
Yidan Ding ◽  
Guoqing Ma ◽  
Shengqing Xiong ◽  
Haoran Wang
Keyword(s):  
Large Scale ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Three Dimensional ◽  
Mining Area ◽  
Model Parameters ◽  
Step Size ◽  
Migration Direction ◽  
Migration Imaging ◽  
Imaging Results

Gravity migration is a fast imaging technique based on the migration concept to obtain subsurface density distribution. For higher resolution of migration imaging results, we propose a 3D regularized focusing migration method that implements migration imaging of an entire gravity survey with a focusing stabilizer based on regularization theory. When determining the model parameters, the iterative direction is chosen as the conjugate migration direction, and the step size is selected on the basis of the Wolfe–Powell conditions. The model tests demonstrate that the proposed method can improve the resolution and precision of imaging results, especially for blocky structures. At the same time, the method has high computational efficiency, which allows rapid imaging for large-scale gravity data. It also has high stability in noisy conditions. The developed novel method is applied to interpret gravity data collected from the skarn-type iron deposits in Yucheng, Shandong province. Migration results show that the depth of the buried iron ore in this area is 750–1500 m, which is consistent with the drilling data. We also provide recommendations for further mineral exploration in the survey area. This method can be used to complete rapid global imaging of large mining areas and it provides important technical support for exploration of deep, concealed deposits.

Fault interactions, fault kinematics, and evolution of the structural framework in the Irish Lower Carboniferous

2020 ◽  
Author(s):  
Koen Torremans ◽  
John Conneally ◽  
John Güven ◽  
Robert Doyle ◽  
jiulin Guo ◽  
...  
Keyword(s):  
Base Metal ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Normal Faults ◽  
Integrated Analysis ◽  
Lower Carboniferous ◽  
Fault Systems ◽  
Structural Framework ◽  
Fault Parameters ◽  
Wide Range

<p>Fault systems in the Irish Lower Carboniferous are important in relation to its subsurface groundwater, geothermal and mineral resources. For example, major base metal deposits in the world-class Irish Orefield occur in association with normal faults. Despite their economic importance, however, the fault networks and structural framework at depth are still poorly constrained. The Irish Carboniferous Basin is an excellent area to study the extensional fault systems and evolution of rift basins, given the relatively low amounts of later compressional deformation and metamorphism, and because high-quality subsurface datasets exist from several decades of mineral exploration. Our work aimed at developing a coherent structural framework for the Lower Carboniferous in Ireland, to unravel the geometries and kinematics of faulting in a carbonate-dominated rift basin that developed on top of a strong pre-existing structural template in the underlying basement rocks.</p><p>We have defined the geometry of key fault systems in the rift across a wide range of scales, using three-dimensional integrated analysis of large datasets. These datasets include public and proprietary onshore 2D reflection seismic, mapping, drillhole, micro-palaeontological, aeromagnetic, electromagnetic, and ground gravity data. Our work has revealed the nature of segmentation patterns and interactions of normal faults, including synthetic and conjugate relay zones. Quantification of fault parameters, kinematic analysis and kinematic restoration have allowed us to gain insights into the distribution of extension during rifting in time and space, using growth sequences and facies changes on faults. The analysis of this structural framework in relation to several mineral deposits, and in combination with lithofacies distribution and the development of bathymetry during basin formation, allows us to better understand current and past fluid flow pathways, especially in relation to base metal mineralising events.</p>

The problem of hollow space correction in subsurface gravity surveys

Geophysics ◽  
1983 ◽  
Vol 48 (10) ◽  
pp. 1406-1408
Author(s):  
B. V. Satyanarayana Murty ◽  
P. Chandra Reddy
Keyword(s):  
Mineral Exploration ◽  
Gravity Data ◽  
Surface Gravity ◽  
Gravity Method ◽  
Hollow Space ◽  
Additional Correction ◽  
Computational Work ◽  
Gravity Measurements

In spite of the extensive computational work involved in the reduction of data especially in estimating the effects of terrain, the gravity method has earned its own esteemed place in mineral exploration. Measurement of gravity in subsurface openings such as mine shafts, drives, and adits is much more valuable in mineral exploration and also useful in the planning, design, and maintenance of mines. However, because the anomalies being sought in this context are usually of very small magnitudes, accuracy at every stage of the gravity investigation is essential. Besides those corrections which are known for the surface gravity measurements, an additional correction for the subsurface gravity data is the result of hollow spaces.

Joint inversion of seismic traveltimes and gravity data on unstructured grids with application to mineral exploration

Geophysics ◽  
2012 ◽  
Vol 77 (1) ◽  
pp. K1-K15 ◽  
Author(s):  
Peter G. Lelièvre ◽  
Colin G. Farquharson ◽  
Charles A. Hurich
Keyword(s):  
Seismic Data ◽  
Unstructured Grids ◽  
Joint Inversion ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Physical Property ◽  
Sulfide Deposit ◽  
Earth Model ◽  
Data Set ◽  
First Arrival

Seismic methods continue to receive interest for use in mineral exploration due to the much higher resolution potential of seismic data compared to the techniques traditionally used, namely, gravity, magnetics, resistivity, and electromagnetics. However, the complicated geology often encountered in hard-rock exploration can make data processing and interpretation difficult. Inverting seismic data jointly with a complementary data set can help overcome these difficulties and facilitate the construction of a common earth model. We considered the joint inversion of seismic first-arrival traveltimes and gravity data to recover causative slowness and density distributions. Our joint inversion algorithm differs from previous work by (1) incorporating a large suite of measures for coupling the two physical property models, (2) slowly increasing the effect of the coupling to help avoid potential convergence issues, and (3) automatically adjusting two Tikhonov tradeoff parameters to achieve a desired fit to both data sets. The coupling measures used are both compositional and structural in nature and allow the inclusion of explicitly known or implicitly assumed empirical relationships, physical property distribution information, and cross-gradient structural coupling. For any particular exploration scenario, the combination of coupling measures used should be guided by the geologic knowledge available. We performed our inversions on unstructured grids comprised of triangular cells in 2D, or tetrahedral cells in 3D, but the joint inversion methods are equally applicable to rectilinear grids. We tested our joint inversion methodology on scenarios based on the Voisey’s Bay massive sulfide deposit in Labrador, Canada. These scenarios present a challenge to the inversion of first-arrival traveltimes and we show how joint inversion with gravity data can improve recovery of the subsurface features.

scholarly journals Joint Inversion of 2D Gravity Gradiometry and Magnetotelluric Data in Mineral Exploration

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 541 ◽  
Author(s):  
Rongzhe Zhang ◽  
Tonglin Li
Keyword(s):  
2D Gravity ◽  
Joint Inversion ◽  
Mineral Exploration ◽  
Gravity Data ◽  
Computation Time ◽  
Iteration Algorithm ◽  
Imaging Method ◽  
Gravity Gradiometry ◽  
Magnetotelluric Data ◽  
Data Space

We have developed a mineral exploration method for the joint inversion of 2D gravity gradiometry and magnetotelluric (MT) data based on data-space and normalized cross-gradient constraints. To accurately explore the underground structure of complex mineral deposits and solve the problems such as the non-uniqueness and inconsistency of the single parameter inversion model, it is now common practice to perform collocated MT and gravity surveys that complement each other in the search. Although conventional joint inversion of MT and gravity using model-space can be diagnostic, we posit that better results can be derived from the joint inversion of the MT and gravity gradiometry data using data-space. Gravity gradiometry data contains more abundant component information than traditional gravity data and can be used to classify the spatial structure and location of underground structures and field sources more accurately and finely, and the data-space method consumes less memory and has a shorter computation time for our particular inversion iteration algorithm. We verify our proposed method with synthetic models. The experimental results prove that our proposed method leads to models with remarkable structural resemblance and improved estimates of electrical resistivity and density and requires shorter computation time and less memory. We also apply the method to field data to test its potential use for subsurface lithofacies discrimination or structural classification. Our results suggest that the imaging method leads to improved characterization of geological targets, which is more conducive to geological interpretation and the exploration of mineral resources.

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