scholarly journals A GIS-based method for archival and visualization of microstructural data from drill core samples.

2020 ◽  
Author(s):  
Elliott Holmes
Keyword(s):  
Drill Core ◽  
Core Samples ◽  
Microstructural Data

scholarly journals Drill-Core Mineral Abundance Estimation Using Hyperspectral and High-Resolution Mineralogical Data

2020 ◽  
Vol 12 (7) ◽  
pp. 1218
Author(s):  
Laura Tuşa ◽  
Mahdi Khodadadzadeh ◽  
Cecilia Contreras ◽  
Kasra Rafiezadeh Shahi ◽  
Margret Fuchs ◽  
...  
Keyword(s):  
Machine Learning ◽  
High Resolution ◽  
Ore Deposits ◽  
Machine Learning Algorithms ◽  
Training Data ◽  
Support Vector ◽  
Drill Core ◽  
Data Types ◽  
Mineralogical Characterization ◽  
Core Samples

Due to the extensive drilling performed every year in exploration campaigns for the discovery and evaluation of ore deposits, drill-core mapping is becoming an essential step. While valuable mineralogical information is extracted during core logging by on-site geologists, the process is time consuming and dependent on the observer and individual background. Hyperspectral short-wave infrared (SWIR) data is used in the mining industry as a tool to complement traditional logging techniques and to provide a rapid and non-invasive analytical method for mineralogical characterization. Additionally, Scanning Electron Microscopy-based image analyses using a Mineral Liberation Analyser (SEM-MLA) provide exhaustive high-resolution mineralogical maps, but can only be performed on small areas of the drill-cores. We propose to use machine learning algorithms to combine the two data types and upscale the quantitative SEM-MLA mineralogical data to drill-core scale. This way, quasi-quantitative maps over entire drill-core samples are obtained. Our upscaling approach increases result transparency and reproducibility by employing physical-based data acquisition (hyperspectral imaging) combined with mathematical models (machine learning). The procedure is tested on 5 drill-core samples with varying training data using random forests, support vector machines and neural network regression models. The obtained mineral abundance maps are further used for the extraction of mineralogical parameters such as mineral association.

The magnetization of oceanic crust: contribution to knowledge from the Troodos, Cyprus, ophiolite

1991 ◽  
Vol 28 (11) ◽  
pp. 1812-1826 ◽  
Author(s):  
James M. Hall ◽  
Charles C. Walls ◽  
Jing-Sui Yang ◽  
S. Lata Hall ◽  
Abdul Razzak Bakor
Keyword(s):  
Lower Limit ◽  
Oceanic Crust ◽  
Drill Hole ◽  
Extensive Study ◽  
Drill Core ◽  
Average Depth ◽  
Ocean Drilling Program ◽  
Ocean Drilling ◽  
Core Samples ◽  
Key Questions

An extensive study of a segment of the Troodos, Cyprus, ophiolite using both outcrop and drill-core samples, and extending from the sediment–extrusive interface through sheeted dikes to cumulate ultramafics, has allowed a number of key questions regarding the magnetization of oceanic crust to be addressed. These include the number of strongly magnetized intervals with depth, their lateral variability and controls on their occurrence. Comparison has also been made with the section in Ocean Drilling Program (ODP) hole 504B, and a reinterpretation of its constructional setting is offered.Two strongly magnetized intervals occur in the area studied. The upper is in the extrusive sequence, extends on average from 0.2 to 0.6 km depth, and has a thickness of ~0.4 km. Here magnetization is dominated by remanence. The lower interval extends from the lowest level at which flows occur with dikes (average depth = 0.9 km) into the Sheeted Complex (average depth = 1.2 km) and has a thickness of 0.3 km. Here magnetization is dominantly induced. No other strongly magnetized intervals occur in the section. The extent of dike intrusion is closely related to the position of the lower limit of the high-remanence layer and to the occurrence of the high induced magnetization layer. In both cases the replacement of primary magnetite, which can carry a strong remanence, by magnetically soft secondary magnetite appears to be the controlling process.Comparison of the Troodos and hole 504B magnetization profiles shows close similarity in the upper, remanence-dominated magnetic interval. The absence of the deeper interval of high induced magnetization in the hole 504B profile is interpreted as meaning that sheeted dikes have not been penetrated by the drill hole.

scholarly journals Modern weathering in outcrop samples versus ancient paleoredox information in drill core samples from a Mesoarchaean marine oxygen oasis in Pongola Supergroup, South Africa

2019 ◽  
Vol 265 ◽  
pp. 330-353 ◽  
Author(s):  
Gülüm Albut ◽  
Balz S. Kamber ◽  
Annika Brüske ◽  
Nicolas J. Beukes ◽  
Albertus J.B. Smith ◽  
...  
Keyword(s):  
South Africa ◽  
Drill Core ◽  
Core Samples

Mapping of Quaternary sediments in northeastern Ontario using ground electromagnetic methods

Geophysics ◽  
1990 ◽  
Vol 55 (12) ◽  
pp. 1596-1604 ◽  
Author(s):  
G. J. Palacky ◽  
L. E. Stephens
Keyword(s):  
Cost Effective ◽  
Geophysical Data ◽  
Drill Core ◽  
Geologic Mapping ◽  
Quaternary Sediments ◽  
Core Samples ◽  
Bedrock Topography ◽  
Electromagnetic Methods ◽  
Overburden Thickness ◽  
Cost Effective Alternative

Since 1985, the Geological Survey of Canada has been evaluating the suitability of electromagnetic (EM) methods for Quaternary geologic mapping. Initially, a variety of ground EM instruments were tested at the Val Gagné, Ontario, site. The multifrequency horizontal‐loop equipment (APEX MaxMin I) was selected for transect surveys in the Kapuskasing‐Timmins area. After interpretation of ground EM results, 70 holes were drilled in the area using Rotasonic equipment. A correlation of drilling logs and geophysical data shows that clay, till, and sand have distinct EM responses. A constrained inversion of the ground EM data, in which drilling information was used to fix the layer thicknesses, yielded resistivity estimates for sediments encountered in boreholes. The following average resistivities were obtained: clay, 47 Ω⋅m; till, 123 Ω⋅m; sand, 251 Ω⋅m; the respective standard deviations were 7, 35, and 70 Ω⋅m. Resistivities of clays and tills were also determined in the laboratory on drill core samples. The results of the study indicate that resistivities of Quaternary sediments in northeastern Ontario are sufficiently stable to justify using EM methods for their identification. When layering is not too complex, inversion of EM data can be used to determine overburden thickness. For some applications, for which only qualitative scanning of bedrock topography is required (detection of bedrock valleys), ground EM techniques are a cost‐effective alternative to more accurate, but more expensive, seismic methods.

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