Currently, a geologist should manually fill an electronic table while he describes rocks or scratch a description on a blanket. This takes a lot of time and effort. Lots of researchers have developed their approach to autonomous rock classification. Unfortunately, all of them are based on a core column investigation. Most used a traditional approach to image classification based on a statistical analysis of images and machine learning techniques. Modern deep learning techniques were applied to classify and segment core images in this work. An important note is that previous works cover only core column examination, while this paper presents an approach to extract core columns from a core box. Thus, a geologist should not spend time on a manual description of the core or extraction of separate images out of a core box. This can be done by applying the developed algorithms described in this work. The algorithms were also included in a system which became worldwide available software.

The Bald Mountain mining district has produced about 2 million ounces (Moz) of Au. Geologic mapping, field relationships, geochemical data, petrographic observations, fluid inclusion characteristics, and Pb, S, O, and H isotope data indicate that Au mineralization was associated with a reduced Jurassic intrusion. Gold deposits are localized within and surrounding a Jurassic (159 Ma) quartz monzonite porphyry pluton and dike complex that intrudes Cambrian to Mississippian carbonate and clastic rocks. The pluton, associated dikes, and Au mineralization were controlled by a crustal-scale northwest-trending structure named the Bida trend. Gold deposits are localized by fracture networks in the pluton and the contact metamorphic aureole, dike margins, high-angle faults, and certain strata or shale-limestone contacts in sedimentary rocks. Gold mineralization was accompanied by silicification and phyllic alteration, ±argillic alteration at shallow levels. Although Au is typically present throughout, the system exhibits a classic concentric geochemical zonation pattern with Mo, W, Bi, and Cu near the center, Ag, Pb, and Zn at intermediate distances, and As and Sb peripheral to the intrusion. Near the center of the system, micron-sized native Au occurs with base metal sulfides and sulfosalts. In peripheral deposits and in later stages of mineralization, Au is typically submicron in size and resides in pyrite or arsenopyrite. Electron microprobe and laser ablation ICP-MS analyses show that arsenopyrite, pyrite, and Bi sulfide minerals contain 10s to 1,000s of ppm Au. Ore-forming fluids were aqueous and carbonic at deep levels and episodically hypersaline at shallow levels due to boiling. The isotopic compositions of H and O in quartz and sericite and S and Pb in sulfides are indicative of magmatic ore fluids with sedimentary sulfur. Together, the evidence suggests that Au was introduced by reduced S-bearing magmatic fluids derived from a reduced intrusion. The reduced character of the intrusion was caused by assimilation of carbonaceous sedimentary rocks.

Tertiary faults dismember the area and drop down the upper part of the mineralizing system to the west. The abundant and widespread kaolinite in oxide ores is relatively disordered (1A polytype) and has δD and δ18O values suggestive of a supergene origin. The deep weathering and oxidation of the ores associated with exhumation made them amenable to open-pit mining and processing using cyanide heap leach methods.

The theme of this book is the study of basaltic volcanism as a stage in planetary evolution: to use the eruption of lava from the interior of a planet as evidence of the thermal and chemical processes of the planet. All lavas extruded on a planet’s surface can provide information about events in the interior. From a petrologic point of view, however, it is the more primitive lavas, which rise to the surface of a planet with minimal changes, that can provide the most information about the interior. In general, these more primitive lavas are basalts and so in Chapter 1 our sampling has concentrated on basaltic rocks.