Observations on the Appalachian-Caledonide ore province and their influence on the development of stratiform ore genesis theory; a short historical review

Stanton, R. L.

doi:10.2113/gsecongeo.79.7.1428

Cited by 4 publications

(4 citation statements)

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“…More recently the present writer has put forward evidence indicating that several other silicates (epidote, sillimanite, cordierite and grossular-andradite) may arise, at least in some cases, directly from precursor materials during regional metamorphism (Stanton , 1983(Stanton , 1984(Stanton and 1987.…”

Section: (C) Earlier Suggestions Concerning Precursorsmentioning

confidence: 95%

“…This brings us to the case of the abundant almandine garnet that commonly occurs as a conspicuous constituent of the small banded (bedded) iron formations now recognized as an almost-ubiquitous component of stratiform ore environments in regionally metamorphosed volcanic settings. Examples are widespread in the Willyama (Broken Hill) Province of New South Wales (Richards 1966;Stanton 1972Stanton , 1976, the Grenville (Adirondacks) Province of northern U.S.A. (Buddington 1966), the Karelian terrane of Finland (see, for example, Isokangas 1978), the Appalachian-Caledonide Province of North America and Norway respectively (McAllister i960;Stanton 1984) and in many other stratiform ore provinces.…”

Section: (B) Extension To the Case Of Almandinementioning

confidence: 99%

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The precursor principle and the possible significance of stratiform ores and related chemical sediments in the elucidation of processes of regional metamorphic mineral formation

Stanton

1989

Phil. Trans. R. Soc. Lond. A

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This contribution is concerned with the regional metamorphism of fine-grained (pelitic) sedimentary materials, and with the pelitic components of coarser sediments. It emphasizes the possible importance of purely chemical sedimentary rocks, and the preservation of chemical patterns within them, in the elucidation of some regional metamorphic mineralogical processes. The materials and examples used come largely from the category of exhalative sediments, of which stratiform metallic sulphide orebodies and their associated exhalites are important members. A few examples come from volcanic rocks that have been altered by exhalative processes. The special significance of chemical sediments stems from their propensity for the development of highly complex metamorphic silicate mineral assemblages within relatively minuscule volumes of rock, and from their commonly sharply defined chemical bedding and chemical sedimentary facies patterns. As the primary nature of such chemical bedding and chemical layering and zoning in completely unmetamorphosed materials is observable and known, and as their sharp boundaries and other well-defined features can be examined in a full range of unmetamorphosed to highly metamorphosed environments, they may be used as extremely sensitive markers for the detection and measurement of any chemical movement that may have taken place during regional metamorphism. Detailed examination of such evidence appears to indicate a general lack of diffusion and reaction, and a common lack of attainment of mineral equilibrium, in the development of the regional metamorphic silicate assemblages of a number of such stratiform ore deposits and their associated exhalative materials. This, together with the common interbedded nature of metamorphic silicate, sulphide, carbonate, etc., and the faithful maintenance of primary sedimentary chemical facies patterns within many exhalative metasediments suggests that the silicates, like the accompanying sulphides and associated compounds, may derive directly and in situ from early-formed precursor materials rather than from extensive elemental diffusion and metamorphic reaction. That particular clays and zeolites derive from specific precursors in many instances has been recognized for a long time. That many metamorphosed bedded oxides (including quartz), together with carbonates, sulphates, sulphides and authigenic silicates such as the feldspars, have derived from sedimentary: diagenetic precursors is self-evident and unavoidable, and establishes precursor derivation for at least some regional metamorphic minerals as a principle, not an hypothesis. What is not known, however, is the extent to which this principle applies to the broader spectrum of metamorphic silicates. The present contribution examines this problem. The evidence of ‘ metamorphic ’ silicates in a range of unmetamorphosed and littlemetamorphosed rocks, in present ocean-floor sediments, in unmetamorphosed volcanic alteration products and in modern geothermal systems is examined. The preservation of possible precursor materials in a variety of rocks, and the synthesis of a number of ‘ metamorphic ’ minerals by low-temperature solution experimentation and in low-temperature industrial products is considered. It is deduced that most of the well-known regional metamorphic minerals may in fact be produced directly from low-temperature sedimentary/diagenetic/alteration materials, and that such precursors may be of simple or complex kind. It is suggested that the direct derivation of regional metamorphic silicates from precursors may resolve the problem of the elusive metamorphic mineral reaction, and that the principal regional metamorphic grade indicators may be the temperatures of precursor transformations rather than temperatures of reactions. Several implications of the precursor principle are then examined: its significance in the interpretation of zoning of regional metamorphic mineral assemblages and mineral chemistry; in considerations of metamorphic grade and the development of grainsize; in the identities of certain metamorphic equilibria, intergrowths and ‘retrograde’ materials; and in the deduction of earlier environments of rock formation and alteration. In this general connection it is proposed that the overall regional metamorphic process may be substantially indigenous: that through their primary nature certain materials, e.g. some andesitic-dacitic volcaniclastic rocks, may be predisposed to metamorphose themselves, and that this may be accentuated by the petro-tectonic setting in which they form, e.g. island arc - eugeosynclinal provinces, with their characteristically inter-related calc-alkaline volcanism, riftrelated palaeogeographical features and highly patterned heat flow. Effects of climate may be superimposed on this: some of the more highly developed regional metamorphic zoning may arise in calc-alkaline volcanic sediments deposited in tropical island arc shelf areas, and in sediments laid down in large saline lakes of continental volcanic rift provinces. From all this it is proposed that the ambit of regional metamorphic petrology may be much wider than currently visualized. Just as precursor-derived oxides, carbonates, sulphates, graphite, pyrite, etc., of high-grade metasedimentary rocks may give clear indications concerning the nature and environments of formation of the original sediments, so the metamorphic silicates may yield subtle insights into palaeoprovenance, palaeogeography, palaeoclimate and a variety of weathering, volcanic alteration, sea-floor hydrothermal and other regimes. The application of metamorphic mineralogy and mineral chemistry to the search for stratiform ores in metamorphosed terranes may constitute one of the major advances in mineral exploration in the near future. It appears that there is considerable scope for further searching for possible precursor material in a variety of rocks and modern sediments (especially those of the present-day volcanic-sedimentary milieu), extension of clay and mixed-layer clay-chlorite-zeolite mineral synthesis in low-temperature-pressure laboratory experiment, and for the investigation of the behaviour of these synthetic products at metamorphic temperatures and pressures.

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Section: (C) Earlier Suggestions Concerning Precursorsmentioning

confidence: 95%

Section: (B) Extension To the Case Of Almandinementioning

confidence: 99%

The precursor principle and the possible significance of stratiform ores and related chemical sediments in the elucidation of processes of regional metamorphic mineral formation

Stanton

1989

Phil. Trans. R. Soc. Lond. A

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“…10c), in which the author postulated that the Lower Paleozoic sulphide ores near Bathurst, New South Wales, had been deposited in a syn-sedimentary, volcanic island arc setting (Stanton 1955). Sullivan was so impressed with the apparent similarities to deposits in northern New Brunswick, that he wrote to Stanton and invited him to come to Bathurst (Stanton 1984). As a result of this letter, Stanton decided to accept a post-doctoral fellowship at Queen's University, which eventually enabled him to visit Bathurst for a month in the fall of 1956.…”

Section: Traduit Par La Traductricementioning

confidence: 99%

Great Mining Camps of Canada 7. The Bathurst Mining Camp, New Brunswick, Part 1: Geology and Exploration History

McCutcheon¹,

Walker²

2019

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The Bathurst Mining Camp of northern New Brunswick is approximately 3800 km2 in area, encompassed by a circle of radius 35 km. It is known worldwide for its volcanogenic massive sulphide deposits, especially for the Brunswick No. 12 Mine, which was in production from 1964 to 2013. The camp was born in October of 1952, with the discovery of the Brunswick No. 6 deposit, and this sparked a staking rush with more hectares claimed in the province than at any time since. In 1952, little was known about the geology of the Bathurst Mining Camp or the depositional settings of its mineral deposits, because access was poor and the area was largely forest covered. We have learned a lot since that time. The camp was glaciated during the last ice age and various ice-flow directions are reflected on the physiographic map of the area. Despite abundant glacial deposits, we now know that the camp comprises several groups of Ordovician predominantly volcanic rocks, belonging to the Dunnage Zone, which overlie older sedimentary rocks belonging to the Gander Zone. The volcanic rocks formed during rifting of a submarine volcanic arc on the continental margin of Ganderia, ultimately leading to the formation of a Sea of Japan-style basin that is referred to as the Tetagouche-Exploits back-arc basin. The massive sulphide deposits are mostly associated with early-stage, felsic volcanic rocks and formed during the Middle Ordovician upon or near the sea floor by precipitation from metalliferous fluids escaping from submarine hot springs. The history of mineral exploration in the Bathurst Mining Camp can be divided into six periods: a) pre-1952, b) 1952-1958, c) 1959-1973, d) 1974-1988, and e) 1989-2000, over which time 45 massive sulphide deposits were discovered. Prior to 1952, only one deposit was known, but the efforts of three men, Patrick (Paddy) W. Meahan, Dr. William J. Wright, and Dr. Graham S. MacKenzie, focused attention on the mineral potential of northern New Brunswick, which led to the discovery of the Brunswick No. 6 deposit in October 1952. In the 1950s, 29 deposits were discovered, largely resulting from the application of airborne surveys, followed by ground geophysical methods. From 1959 to 1973, six deposits were discovered, mostly satellite bodies to known deposits. From 1974 to 1988, five deposits were found, largely because of the application of new low-cost analytical and geophysical techniques. From 1989 to 2000, four more deposits were discovered; three were deep drilling targets but one was at surface. RÉSUMÉLe camp minier de Bathurst, dans le nord du Nouveau-Brunswick, s’étend sur environ 3 800 km2 à l’intérieur d’un cercle de 35 km de rayon. Il est connu dans le monde entier pour ses gisements de sulfures massifs volcanogènes, en particulier pour la mine Brunswick n° 12, exploitée de 1964 à 2013. Le camp est né en octobre 1952 avec la découverte du gisement Brunswick n° 6 et a suscité une ruée au jalonnement sans précédent avec le plus d’hectares revendiqués dans la province qu’à présent. En 1952, on savait peu de choses sur la géologie du camp minier de Bathurst ou sur les conditions de déposition de ses gisements minéraux, car l’accès était très limité et la zone était en grande partie recouverte de forêt. Nous avons beaucoup appris depuis cette période. Le camp était recouvert de glace au cours de la dernière période glaciaire et diverses directions d’écoulements glaciaires sont révélées sur la carte physiographique de la région. Malgré des dépôts glaciaires abondants, nous savons maintenant que le camp comprend plusieurs groupes de roches ordoviciennes à prédominance volcanique, appartenant à la zone Dunnage, qui recouvrent de plus vieilles roches sédimentaires de la zone Gander. Les roches volcaniques se sont formées lors du rifting d’un arc volcanique sous-marin sur la marge continentale de Ganderia, ce qui a finalement abouti à la formation d’un bassin de type mer du Japon, appelé bassin d’arrière-arc de Tetagouche-Exploits. Les gisements de sulfures massifs sont principalement associés aux roches volcaniques felsiques de stade précoce et se sont formés au cours de l’Ordovicien moyen sur ou proche du plancher océanique par la précipitation de fluides métallifères s’échappant de sources chaudes sous-marines. L’histoire de l’exploration minière dans le camp minier de Bathurst peut être divisée en six périodes: a) antérieure à 1952, b) 1952-1958, c) 1959-1973, d) 1974-1988 et e) 1989-2000, au cours desquelles 45 dépôts de sulfures massifs ont été découverts. Avant 1952, un seul dépôt était connu, mais les efforts de trois hommes, Patrick (Paddy) W. Meahan, William J. Wright et Graham S. MacKenzie, ont attiré l’attention sur le potentiel minier du nord du Nouveau-Brunswick, ce qui a conduit à la découverte du gisement Brunswick n° 6 au mois d’octobre 1952. Dans les années 50, 29 gisements ont été découverts, résultant en grande partie de l’utilisation de levés aéroportés, suivis de campagnes géophysiques terrestres. De 1959 à 1973, six gisements ont été découverts. Ce sont essentiellement des formations satellites de gisements connus. De 1974 à 1988, cinq gisements ont été découverts, principalement grâce à l’utilisation de nouvelles techniques analytiques et géophysiques peu coûteuses. De 1989 à 2000, quatre autres gisements ont été découverts. Trois étaient des cibles de forage profondes, mais l’un était à la surface.

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“…Active SMS deposits form in a wide range of tectonic settings from mid-ocean ridges (Humphris et al, 1995) to island arcs (de Ronde et al, 2011) and back-arc basins (Herzig et al, 1998a). Differences in metal enrichment among tectonic environments are recognised and are thought to relate to variations in both source rock metal content and magmatic volatile flux into the hydrothermal system; however, the relative contribution of metal from these two sources remains poorly constrained and actively debated (Hedenquist and Lowenstern, 1994;Large, 1992;Moss et al, 2001;Ohmoto, 1996;Patten et al, 2020;Stanton, 1984;Yang and Scott, 1996). Linking processes between ancient and active seafloor hydrothermal systems is key to understanding factors that control metal enrichment in ancient VMS deposits, how this varies with VMS deposit maturation, and how this signature is preserved in ancient on-land analogues -a tool that can be utilised in mineral exploration to assess the potential metal endowment of VMS deposits.…”

Section: Introductionmentioning

confidence: 99%

A missing link between ancient and active mafic-hosted seafloor hydrothermal systems – Magmatic volatile influx in the exceptionally preserved Mala VMS deposit, Troodos, Cyprus

et al. 2021

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Observations on the Appalachian-Caledonide ore province and their influence on the development of stratiform ore genesis theory; a short historical review

Cited by 4 publications

References 25 publications

The precursor principle and the possible significance of stratiform ores and related chemical sediments in the elucidation of processes of regional metamorphic mineral formation

The precursor principle and the possible significance of stratiform ores and related chemical sediments in the elucidation of processes of regional metamorphic mineral formation

Great Mining Camps of Canada 7. The Bathurst Mining Camp, New Brunswick, Part 1: Geology and Exploration History

A missing link between ancient and active mafic-hosted seafloor hydrothermal systems – Magmatic volatile influx in the exceptionally preserved Mala VMS deposit, Troodos, Cyprus

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