The 21st in the series of SEG Foundation-sponsored student field trips provided the opportunity to assess the stratigraphic, structural, and mineralogical characteristics of Tertiary-age low- and high-sulfidation precious metal deposits of the Walker Lane, SW Nevada. Southwest Nevada hosts numerous examples of these deposit types. Tectonism in the region created the basin and range which provides vast areas of geologic exposure. This complex structural history, punctuated with eras of igneous activity, makes exploring and mining in the Great Basin a rewarding experience.

The Skellefte district has been one of the most important mining districts of Europe for the last century, as it hosts close to 90 volcanogenic massive sulfide (VMS) deposits and occurrences, including the Kristineberg, Renström, and Au-rich Boliden VMS deposits. Several lode Au (±Te), porphyry Cu-Au, pegmatite-hosted rare-metal, and Ni deposits and occurrences are present in the district as well, including deposits such as Björkdal and Tallberg. This trip visited active mines and advanced-stage exploration and development projects.

Myanmar is richly endowed in natural resources that include tin, tungsten, copper, gold, zinc, lead, nickel, and silver, as well as gemstones. The material covered over a nine-day field trip explores the country’s complex geology, which reflects a collisional history stretching from the Late Triassic to at least Miocene, sited at the eastern end of the India-Asia suture. The country can be divided into three principal metallotects: the Wuntho-Popa magmatic arc, with granites and associated porphyry-type and epithermal Cu-Au mineralization; the Slate Belt (also called the Mogok-Mandalay-Mergui Belt), with multiple precollisional I-type and postcollisional S-type crustal melt granites that host significant tin-tungsten mineralization, and which also are host to a number of orogenic gold deposits; and the Shan Plateau with massive sulfide-type and also MVT-style lead-zinc-silver deposits.

This field course provides opportunities to assess the stratigraphic, structural, and mineralogical complexities of Carlin-type disseminated gold deposits of northern Nevada, the giant carbonate replacement (manto) gold deposits, and will discuss the geologic models that have been proposed for their formation. This was a virtual field trip.

This guidebook on the gold and magmatic Cu-Ni-PGE deposits of Lapland highlights deposit characteristics, their diversity, and temporal and spatial relationships. The tectonic setting and relationship to the general geodynamic evolution of the Fennoscandian Shield are examined as well. In addition, deposit-scale controls and structural features are considered to understand the ore genesis. Areas covered include the Portimo Layered Complex, Kevitsa intrusion, Pahtavaara gold mine, Sakatti deposit, Risti and Launi gold projects, Mustajärvi orogenic gold occurrence, Suurikuusikko gold deposit (Kittilä mine), and Rjapalot gold-cobalt project.

The material covered over this six-day field trip explores the regional stratigraphy, tectonic setting, and mineral deposits of the central Sierra Madre Occidental and western part of the Mesa Central in Mexico. The course builds on similar field trips held in 1997, 2003, and 2014, adding updates of the geology based on new studies and opening of new roads in this rugged and poorly accessible region. A completely new section presents a detailed overview of the geology of the classic San Dimas mining district and the Sabinas and La Colorada mines. A road trip log with descriptions of each stop is included.

Over the course of a week, participants of this student field trip visited several epithermal and porphyry precious metal deposits in the Maricunga belt and copper-silver IOCG and manto deposits in northern Chile, with visits to active open-pit and underground operations, including Punta del Cobre, Atacama Kozan, Las Luces, El Guanaco, and Marimaca, as well as drill core reviews of exploration projects at Caspiche, Cerro Casale, and Salares Norte. The geology and mineralization of these deposits was studied in the context of regional and local geological settings, focusing on their similarities and differences, ore resources, deposit models, and exploration methods; the strong structural control on most of the deposits was highlighted. The guidebook includes detailed course itinerary and route map.

The Colorado Plateau and specifically the Paradox basin of southeastern Utah, southwestern Colorado, and adjacent states provides a superbly exposed natural laboratory to consider what drives fluid flow in sedimentary basins and what are its manifold consequences for mineral resources. The rich geologic context reveals multiple types and scales of fluid-driven and fluid-mediated phenomena. The focus of the material from this field trip is on Cu and U(-V) ore systems in Mesozoic rocks, their settings and deposit-scale geologic characteristics, evidence for their timing, their links to broader flow systems including antecedent or contemporaneous petroleum systems, and what colocated modern fluid systems can illustrate. The guidebook includes a course map for the four-day trip.

This field course examined active mines and exploration projects, geochemical and geophysical data, and tectonic setting to address a series of questions about lithium and gold deposits. The course was held over four days in conjunction with the SEG 2018 Conference and started and ended in Reno, Nevada. The detailed road log describes stops at Angel Island, Clayton Valley, Eastside Project, Tonopah, Rhyolite Ridge, Round Mountain, Montezuma Range, and Hasbrouck Mountain.

Student Field Trip 17 visited a number of paleoplacer and orogenic gold deposits throughout southwest Ghana over a week. The itinerary and route map include visits to active open-pit and underground operations, including Damang, Iduapriem, Nkran/Esaase, Obuasi, Prestea-Bogosu, and Wassa, as well as exploration projects at Homase-Akrokerri, all hosted within the Birimian Supergroup. The course material covers the geology and mineralization of these deposits in the context of regional and local geological settings, focusing on their similarities and differences, ore resources, deposit models, and exploration methods.

This guidebook provides copies of the key previously published papers of Climax, Henderson and Leadville districts. This is a departure from the traditional SEG. Guidebook format in that it does not contain new papers of the deposits. The Climax and Henderson porphyry Mo and Leadville district carbonate-hosted manto deposits are within the Colorado Mineral Belt, a mineralized belt that contains the mostproductive porphyry molybdenum and some of the largest base- and precious-metal manto deposits in the world. Since the discovery of molybdenum-bearing stockwork veinlets at Climax in 1879, the Urad orebody in 1914, and Henderson in 1964, collectively these mines have produced over 2.9 billion pounds of Mo. In late 2009, Henderson produced its billionth pound of molybdenum and in 2012 Climax commissioned a new concentrator and is now producing ore from an open pit. Significant published reserves remain and for both Climax and Henderson that total 1 billion pounds of molybdenum metal. The Leadville district is noted for its long history of production having produced 3.1 million ounces of gold, 260 million ounces of silver and significant base metals since its discovery in 1860, research on carbonate-hosted Ag-Zn-Pb-(Au) deposits, and the founding of the Guggenheim mining fortune, including the formation of ASARCO, Inc.