Brian J. Skinner Award

Article: Exploration Implications of Multiple Formation Environments of Advanced Argillic Mineral

Authors: J. Hedenquist, A. Arribas

Publication: Economic Geology, Vol. 117, No. 3, p. 609-643

This seminal paper, written by two Past Presidents of the Society, hopefully does not represent the culmination of their illustrious careers, but instead a hint of more to follow. This synthesis is built on dozens of papers written by the authors spanning four decades. This study describes complex, overprinting patterns of sericitic, and intermediate and advanced argillic alteration in the context of evolving magmatic-hydrothermal systems, and their eventual collapse. These patterns and their underlying processes form a conceptual model that is illustrated within a field-based geologic framework to serve as a guide for exploration for important ore deposit types such as epithermal, porphyry and volcanic-hosted massive sulfide deposits. The impact of this paper will be felt for years to come.

Article: Are Vapor-Like Fluids Viable Ore Fluids for Cu-Au-Mo Porphyry Ore Formation?

Authors: N. Hurtig, A. Migdisov, A. Williams-Jones

Publication: Economic Geology, Vol. 116, No. 7, p. 1599-1624

This study, built on decades of geologic observations on porphyry copper deposits, tackles the elusive question of the role of the vapor phase in the formation of this economically important deposit type. The investigation combines geologic observations, fluid inclusion data, thermodynamic data, and numerical modeling of end-member bounding processes to describe the relationships of parameters such as pressure, temperature, and fluid composition to the formation of overprinting ore shells in porphyry copper systems and related epithermal deposits. This demonstration of the important role of vapor transport of metals and its relation to metal ratios in this important deposit type should significantly influence future exploration strategies for porphyry copper and related epithermal systems.

Article: The Onto Cu-Au Discovery, Eastern Sumbawa, Indonesia: A Large, Middle Pleistocene Lithocap-Hosted High-Sulfidation Covellite-Pyrite Porphyry Deposit

Authors: D. Burrows, M. Rennison, D. Burt, R. Davies

Publication: Economic Geology, Vol. 115, No. 7, p. 1385-1412

This well executed, meticulous study describes the genetic framework for the discovery of a recent, extremely young, somewhat atypical giant or supergiant ore deposit. The research will undoubtedly change the paradigm for the exploration of blind hybrid porphyry copper-gold/high sulfidation epithermal systems. This paper will surely have a lasting impact in the field of economic geology due to its strong foundation in observational data from the field and drill core.

Article: The Metal Content of Magmatic-Hydrothermal Fluids and Its Relationship to Mineralization Potential

Author: A. Audétat

Publication: Economic Geology, Vol. 113, No. 6, p. 1033-1056

This well executed, meticulous study addresses the age-old question of nature versus nurture for ore-forming magmatic-hydrothermal systems. It is written and readily comprehensible by any economic geologist. The research compiled, and carefully screened published fluid inclusion chemistry data to enable modeling of the geochemical evolution of magmatic fluids. The study concluded that for some metals, magmatic systems are endowed with anomalous concentrations of metals leading to ore formation, whereas for other metals, factors such as the size of the intrusion, the depth of emplacement, or the tectonic stress regime may be critical for generating ore. This paper will surely have a lasting impact in the field of economic geology due to its strong foundation in observational data from the field and drill core.

Beginning in 2020, SEG will shift the date for all awards listed below to the year in which they are presented rather than the year in which awardees are nominated. Lectureships already satisfy this condition.

Article: Geology of the Boyongan and Bayugo Porphyry Cu‐Au Deposits: An Emerging Porphyry District in Northeast Mindanao, Philippines

Authors: D. Braxton, D. Cooke, A. Ignacio, P. Waters

Publication: Economic Geology, Vol. 113, No. 1, p. 83-131

This well executed and detailed study provides an excellent summary of the geology, alteration, and mineralization of the Boyongan and Bayugo porphyry copper‐gold prospects in the Philippines. It presents an outstanding integration of observational data with the regional and local tectonostratigraphic and metallogenic setting; what these deposits look like and their mineralization, alteration, and grade footprints; and the interrelationships among magmatism, hydrothermal alteration and mineralization and how the deposits formed. It is also well written, beautifully illustrated, and readily comprehensible by any economic geologist. This paper will surely have a lasting impact in the field of economic geology due to its strong foundation in observational data from the field and drill core.

Article: What Caused the Formation of the Giant Bingham Canyon Porphyry Cu-Mo-Au Deposit? Insights from Melt Inclusions and Magmatic Sulfides

Authors: D. Zhang, A. Audétat

Publication: Economic Geology, Vol. 112, No. 2, p. 221–244

This study used a relatively new technique (LA-ICP-MS) to analyze melt inclusions to shed light on fundamental processes related to the origin of giant ore deposits—namely, the role of magma mixing to bring together the key ingredients for ore genesis. This paper will surely have a lasting impact on the field of economic geology.

Honorable Mention

Article: The Anatomy of an Antibacterial Clay Deposit: A New Economic Geology

Authors: K.D. Morrison, S.N. Williams, L.B. Williams

Publication: Economic Geology, Vol. 112, No. 7, p. 1551-1570

Article: Apatite Trace Element Compositions: A Robust New Tool for Mineral Exploration

Authors: M. Mao, A. Rukhlov, S. Rowins, J. Spence, L. Coogan

Publication: Economic Geology, Vol. 111, No. 5, p. 1187-1222

This well-executed study on apatite mineral chemistry, using both standard and cutting-edge analytical techniques, shows that apatite provenance can be used in mineral assessment surveys and other provenance-related geologic studies. The paper strikes a nice balance between the complex mineral chemistry, statistical analysis of a large data set, and highlighting its potential use as a real-world exploration tool. With its innovative approach to a practical problem faced by numerous researchers and explorationists, this paper will have lasting applications in the field of economic geology.

Article: Time Scales of Porphyry Cu Deposit Formation: Insights from Titanium Diffusion in Quartz

Authors: C. Mercer, M. Reed, C. Mercer

Publication: Economic Geology, Vol. 110, No. 3, p. 587-602

This study brings a new quantitative interpretation of quartz zoning, a feature commonly observed in hydrothermal ore deposits, using trace element titanium diffusion profiles to reconstruct time scales of porphyry deposit mineralization. Diffusion modeling is commonly used in igneous petrology, but this study represents one of the first, if not the first, time it has been applied to hydrothermal processes. Thus, it adds a new dimension to our understanding of the duration of ore-forming events, and demonstrates insightful and effective application of a variety of state-of-the-art analytical tools to hydrothermal research. The work represents innovative science applied to a practical problem of great interest to numerous researchers and explorationists. This paper will surely have a lasting impact in the field of economic geology.

Article: The Anatomy of a Buried Submarine Hydrothermal System, Clark Volcano, Kermadec Arc, New Zealand

Authors: C. de Ronde, S. Walker, R. Ditchburn, F. Caratori Tontini, M. Hannington, S. Merle, C. Timm, M. Handler, R. Wysoczanski, V. Dekov, G. Kamenov, E. Baker, R. Embley, J. Lupton, P. Stoffers

Publication: Economic Geology, Vol. 109, No. 8, p. 2261-2292

This innovative study uses integrated submarine mapping, mineralogy, radiogenic and stable isotopes to model extinct and currently active hydrothermal activity as a function of volcano extension and growth. The paper has important implications for the longevity and cyclicity of VMS hydrothermal systems and illustrates the role that submarine volcanic environment plays on the nature of mineralization. The work has implications for global resource assessments as we have likely underestimated the abundance of mineralization in modern environments.

Article: The Metal Content of Silicate Melts and Aqueous Fluids in Subeconomically Mo Mineralized Granites: Implications for Porphyry Mo Genesis

Authors: L. Lerchbaumer, A. Audétat

Publication: Economic Geology, Vol. 108, No. 5, p. 987-1013

This innovative study provides compelling evidence for the origin of granite-hosted molybdenum mineralization including the critical conclusion that barren granitic systems do not necessarily have lower molybdenum contents, relative to those of productive granites. It judiciously uses modern analytical techniques on melt inclusions coupled with experiments and a thoughtful analysis of the existing data on molybdenum and associated metals distribution in magmatic systems.

Article: Hydrologic, Magmatic, and Tectonic Controls on Hydrothermal Flow, Taupo Volcanic Zone, New Zealand: Implications for the Formation of Epithermal Vein Deposits

Authors: J. Rowland, S. Simmons

Publication: Economic Geology, Vol. 107, No. 3, p. 427-457

This carefully constructed and elegantly written paper with superb graphics excels in its technical excellence, innovation, and likely lasting impact that it will have in the field of economic geology — all attributes valued in the Brian J. Skinner Award selection process. The research relies on basic observations and integrates the tectonic, volcanic, and hydrothermal histories of the Taupo Volcanic Zone into a cohesive model that explains the evolution of permeability and fluid flow in the region as it relates to epithermal mineralization. The work has important implications for the exploration for epithermal ore deposits.

Article: A Carbonaceous Sedimentary Source-Rock Model for Carlin-Type and Orogenic Gold Deposits

Authors: R. Large, S. Bull, V. Maslennikov

Publication: Economic Geology, Vol. 106, No. 3, p. 331-358

This beautifully written paper excels in its technical excellence, innovation, and likely lasting impact that it will have in the field of economic geology – all attributes valued in the Brian J. Skinner Award selection process. The research integrates modern, cutting-edge analytical techniques with tectonic, geochemical, and isotopic insights to address a problem that has perplexed economic geologists for decades. The combination of basic science and practical application of this work is to be commended. This paper will fundamentally change our ideas about processes involved in the formation of orogenic and Carlin-type gold deposits.

Article: Evolution of Calc-Alkaline Volcanism and Associated Hydrothermal Gold Deposits at Yanacocha, Peru

Authors: A. Longo, J. Dilles, A. Grunder, R. Duncan

Publication: Economic Geology, Vol. 105, No. 7, p. 1191-1241

Fantastic paper that integrates field mapping, regional stratigraphy, local stratigraphy, and alteration with geochronology and petrology to provide a true understanding of the setting and timing of mineralization and associated alteration at this important epithermal system, and also provides key constraints on how these systems form, their timing, and longevity.

Article: Cordilleran Epithermal Cu-Zn-Pb-(Au-Ag) Mineralization in the Colquijirca District, Central Peru: Deposit-Scale Mineralogical Patterns

Authors: R. Bendezú, L. Fontboté

Publication: Economic Geology, Vol. 104, No. 7, p. 905-944

This beautifully written paper with superb graphics excels in its technical excellence, innovation, and likely lasting impact that it will have in the field of economic geology—all attributes valued in the Skinner Award selection process. The research, spanning scales of observation from deposit to microscopic scale, intelligently uses district-scale mapping and geochemistry to provide new insight to the geological and geochemical processes that formed the deposit. The integration of field and laboratory investigations leads to the recognition of a complex paragenesis and multi-stage evolution of this epithermal setting and provides understanding directly applicable to exploration.

Article: Fluid Inclusion Evidence for Magmatic-Hydrothermal Fluid Evolution in the Porphyry Copper-Molybdenum Deposit at Butte, Montana

Authors: B. Rusk, M. Reed, J. Dilles

Publication: Economic Geology, Vol. 103, No. 2, p. 307-334

This paper presents a thorough and innovative approach to investigating a challenging topic—the hydrothermal evolution of a complex, world class porphyry copper system. The authors elegantly document, through detailed fluid inclusion studies, the importance of physical and chemical changes in the evolution a single, low salinity hydrothermal fluid rather than invoking multiple fluids as has been proposed for numerous other porphyry systems. Their study further describes how differing precipitation mechanisms account for the copper and molybdenum mineralization. Finally, their results suggest that Butte formed at some of the greatest depths known for economic porphyry copper-style mineralization—a thought provoking conclusion.

Article: The LaRonde Penna World-Class Au-Rich Volcanogenic Massive Sulfide Deposit, Abitibi, Québec: Mineralogy and Geochemistry of Alteration and Implications for Genesis and Exploration

Authors: B. Dubé, P. Mercier-Langevin, M. Hannington, B. Lafrance, G. Gosselin, P. Gosselin

Publication: Economic Geology, Vol. 102, No. 4, p. 633-666

This paper is one of the few detailed studies of a world-class gold-rich volcanogenic massive sulfide deposit, the LaRonde-Penna deposit, which arguably may be the “type example” for this economically important style of mineralization. The study is an eloquent integration of geological, mineralogical, and geochemical information that provides concrete recommendations for exploration. The authors present compelling evidence bearing on one of the classic debates in economic geology regarding magmatic versus non-magmatic (seawater) contributions to VMS systems. They propose a new model for the relationship between low- and high-sulfidation sea-floor systems, and in contrast to earlier models suggest that both end-members can form in the same district or even within a single hydrothermal system.

Article: Igneous Geology of the Carlin Trend, Nevada: Development of the Eocene Plutonic Complex and Significance for Carlin-Type Gold Deposits

Authors: M. Ressel, C. Henry

Publication: Economic Geology, Vol. 101, No. 2, p. 347-383

This paper is the product of a significant effort to increase the awareness of igneous rocks and magmatic activity in the Carlin Trend. It characterizes and contrasts Jurassic, Cretaceous, Eocene, and Miocene intrusions in the northern Great Basin using a diverse data set of emplacement styles, mineralogy, compositions and hard-won Ar-Ar ages. These data provide a comprehensive temporal framework for igneous rocks that are spatially associated with more than 40 gold deposits of the Carlin Trend. The paper integrates a large amount of new and previously published information and succeeds in the technically and conceptually challenging task of combining geological mapping, geochronology, igneous petrology and geophysics to address a major question in economic geology.

Article: Evolution of a Submarine Magmatic-Hydrothermal System: Brothers Volcano, Southern Kermadec Arc, New Zealand

Authors: C. de Ronde, M. Hannington, P. Stoffers, I. Wright, R. Ditchburn, A. Reyes, E. Baker, C. Massoth, J. Lupton, S. Walker, R. Greene, C. Soong, J. Ishibashi, G. Lebon, C. Bray, J Resing

Publication: Economic Geology, Vol. 100, No. 6, p. 1097-1133

This paper presents an elegant and detailed dissection of an active submarine hydrothermal system in a critical transitional geologic environment. Economic geologists have long recognized the significance of volcanic arcs as favorable terrains for mineralization. However, ore deposits typically form a bimodal distribution with end members divided between terrestrial and submarine representatives. The innovative combination of geologic and geochemical studies that form the basis of this contribution provides unique insights of the interplay between magmatic fluids and evolved seawater in ore-forming systems on the sea floor.

Article: Henderson Porphyry Molybdenum System, Colorado: I. Sequence and Abundance of Hydrothermal Mineral Assemblages, Flow Paths of Evolving Fluids, and Evolutionary Style

Authors: E. Seedorff, M. Einaudi

Publication: Economic Geology, Vol. 99, No. 1, p. 3-37

This paper presents a comprehensive and detailed analysis of the geology, alteration and mineralization of a classic and economically significant porphyry molybdenum deposit. The geological mapping, core logging and paragenetic studies that form the basis of this paper reflect the careful field and laboratory observations necessary to constrain the history of mineralization and to present a full and complete picture of a complex mineralizing system. The body of observations on Henderson clearly show how multiple overprinting hydrothermal events lead to the formation of world-class orebodies. Together with the companion paper on the geochemical evolution of the Henderson system, this work provides new insight into the essential processes that form porphyry deposits and sets a new standard for their documentation.

Article: Geology of the Bajo de la Alumbrera Porphyry Copper-Gold Deposit, Argentina

Author: J. Proffett

Publication: Economic Geology, Vol. 98, No. 8, p. 1535-1574

This paper presents an exhaustive descriptive account of the geology, alteration and mineralization of a complex, economically significant porphyry copper-gold deposit. The geological mapping, which forms the basis for this contribution, exemplifies the type of careful fieldwork and observations necessary to reliably constrain the history of these deposits and to present a full and complete picture of the mineralizing process. The body of observations in this paper is the result of an exceptional effort, both in the field and in the preparation of the accompanying maps. It is an example of how detailed geological observations underpin the interpretation of ore-forming systems and how our science relies on this effort. The carefully prepared maps are expected to have a significant impact in both research and teaching and are an important milestone for the journal. They set a high standard of technical excellence for future contributions of this type.

Article: Miocene Landscape Evolution and Geomorphologic Controls on Epithermal Processes in the El Indio-Pascua Au-Ag-Cu Belt, Chile and Argentina

Author: T. Bissig, A. Clark, J Lee, C Hodgson

Publication: Economic Geology, Vol. 97, No. 5, p. 971-996

This paper presents an integrated study of the geochronology, mineralization and landscape evolution in the El Indio-Pascua belt. Taking advantage of the superb exposures of the Andes, the authors combine innovative geomorphologic reconstructions (aided by GIS technology), high-precision geochronology, and ore deposit geology to show how changing landscape can influence fluid evolution and affect mineralizing processes. Despite the implied importance of the paleosurface in epithermal environments, the means to link landscape evolution to mineralizing processes has eluded economic geologists. The approach presented in this paper is considered both innovative and provocative and hopefully stimulate new discussion and research on the role of surface evolution in the paleohydrology of ore-forming systems.