||Article / Author(s) / Vol. No.
||Hydrologic, Magmatic, and Tectonic Controls on Hydrothermal Flow, Taupo Volcanic Zone, New Zealand: Implications for the Formation of Epithermal Vein Deposits
J.V. Rowland, S.F. Simmons
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. Thus, this research will surely have a lasting impact in the field of economic geology.
||A carbonaceous sedimentary source-rock model for Carlin-type and orogenic gold deposits
R.R. Large, S.W. Bull, V.V. Maslennikov
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. The conclusions of this contribution will surely have a lasting impact in the field of economic geology.
||Evolution of Calc-Alkaline Volcanism and Associated Hydrothermal Gold Deposits at Yanacocha, Peru
A.A. Longo, J.H. Dilles, A.L. Grunder, R. Duncan
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. Has very broad implications.
||Cordilleran Epithermal Cu-Zn-Pb-(Au-Ag) Mineralization in the Colquijirca District, Central Peru: Deposit-Scale Mineralogical Patterns
R. Bendezú, L. Fontboté
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. Thus, the conclusions of this contribution will surely have a lasting impact in the field of economic geology.
||Fluid Inclusion Evidence for Magmatic-Hydrothermal Fluid Evolution in the Porphyry Copper Molybdenum Deposit at Butte, Montana
B.G. Rusk, M.H. Reed, J.H. Dilles
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.
||The LaRonde-Penna world-class Au-rich volcanogenic massive sulfide deposit, Abitibi, Quebec: mineralogy and geochemistry of alteration and implications for genesis and exploration
B. Dubé, P. Mercier-Langevin, M. Hannington, B. Lafrance, G. Gosselin, P. Gosselin
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. The conclusions of this contribution will surely have a lasting impact in the field of economic geology.
||Igneous Geology of the Carlin Trend, Nevada: Development of the Eocene Plutonic Complex and Significance for Carlin-Type Gold Deposits
M.W. Ressel, C.D. Henry
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.
||Submarine magmatic-hydrothermal system: Brothers Volcano, Southern Kermadec Arc, New Zealand
C.E.J. de Ronde, M.D. Hannington, P. Stoffers, I.E. Wright, R.G. Ditchburn, A.G. Reyes, E.T. Baker, C.J. Massoth, J.E. Lupton, S.L. Walker, R.R. Greene, C.W.R. Soong, J. Ishibashi, G.T. Lebon, C.J. Bray, J.A Resing
Vol. 100, No. 6, p. 1096-1133
|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.
||Henderson Porphyry Molybdenum System, Colorado: I. Sequence and abundance of hydrothermal mineral assemblages, flow paths of evolving fluids, and evolutionary style (Part 1)
E. Seedorff, M.T. Einaudi
Vol. 99, No. 1, p. 3-38
|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.
||Geology of the Bajo de la Alumbrera porphyry copper-gold deposit, Argentina
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.
||Miocene Landscape Evolution and Geomorphologic Controls on Epithermal Processes in the El Indio-Pascua Au-Ag-Cu Belt, Chile and Argentina
T. Bissig, A.H. Clark, J.K.W. Lee, C.J. Hodgson
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.