Tectonic Controls on Early Mesozoic Paired Alkaline Porphyry Deposit Belts (Cu-Au   Ag-Pt-Pd-Mo) Within the Canadian Cordillera

Logan, James M.; Mihalynuk, Mitchell G.

doi:10.2113/econgeo.109.4.827

Cited by 83 publications

(66 citation statements)

References 103 publications

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“…The results also provide new insights into the geometry and petrologic evolution of the region. This study supports the suggestion that this Paleoproterozoic metallogenic zone is not directly comparable to many other Precambrian IOCG examples (Groves et al, 2010), but rather we show it is comparable to the Andean styles of IOCG mineralization preserved in Chile and Peru (e.g., Sillitoe, 2003;Groves et al, 2010;Chen et al, 2013), as well as alkaline porphyry Cu-Au deposits that occur during episodes of extensional rifting within greater Cordilleran -type orogenic events Richards and Mumin, 2013a,b;Logan and Mihalynuk, 2014;Richards et al, in press). …”

Section: Accepted M Manuscriptcontrasting

confidence: 48%

“…Such active margin characteristics are also attributes of many Phanerozoic Cu-Au porphyry deposits, an alkali endmember in porphyry deposits (Müller and Groves, 1993;Wang et al, 2006;Logan and Mihalynuk, 2014). Additional similarities include the alteration assemblages associated with these Cu-Au porphyry deposits, e.g., extensive albititization and magnetite-actinolite-apatite veins and replacements assemblages, and/or skarns, in the host-rocks (e.g., Logan and Mihalynuk, 2014). These Cu-Au porphyry environments are related to active margin extension, in some cases similar to that depicted for the Paleoproterozoic Great Bear (Wang et al, 2006) and others are related to slab tears, which are invoked to account for alkali magmatism (Logan and Mihalynuk, 2014).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…The overall extensional environment suggested for Great Bear deposits is particularly reminiscent of the early Cretaceous deposits in the northern Andes (e.g., Sillitoe 2003). Such active margin characteristics are also attributes of many Phanerozoic Cu-Au porphyry deposits, an alkali endmember in porphyry deposits (Müller and Groves, 1993;Wang et al, 2006;Logan and Mihalynuk, 2014). Additional similarities include the alteration assemblages associated with these Cu-Au porphyry deposits, e.g., extensive albititization and magnetite-actinolite-apatite veins and replacements assemblages, and/or skarns, in the host-rocks (e.g., Logan and Mihalynuk, 2014).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

“…Additional similarities include the alteration assemblages associated with these Cu-Au porphyry deposits, e.g., extensive albititization and magnetite-actinolite-apatite veins and replacements assemblages, and/or skarns, in the host-rocks (e.g., Logan and Mihalynuk, 2014). These Cu-Au porphyry environments are related to active margin extension, in some cases similar to that depicted for the Paleoproterozoic Great Bear (Wang et al, 2006) and others are related to slab tears, which are invoked to account for alkali magmatism (Logan and Mihalynuk, 2014). A key commonality among all of these is the presence of subducted pelagic sediments and associated mantle metasomatism (e.g., Wang et al, 2006;Richards and Mumin, 2013a).…”

Section: Accepted M Manuscriptmentioning

confidence: 99%

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A Paleoproterozoic Andean-type iron oxide copper-gold environment, the Great Bear magmatic zone, Northwest Canada

Ootes

Snyder

Davis

et al. 2017

Ore Geology Reviews

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Iron oxide copper-gold (IOCG) and associated iron-oxide apatite (IOA) styles of metallic mineralization are recognized throughout the Paleoproterozoic Great Bear magmatic zone of the northwest Canadian Shield. The Great Bear magmatic zone was constructed between ca. 1876 and 1855 Ma on top of the older Hottah terrane, which preserves continental arc magmatism that began around ca. 2.0 to 1.97 Ga and continued between ca. 1.93 and 1.89 Ga. The Great Bear represents the final stages of ca. 150 million years of intermittent and pulsed magmatism related to an evolving continental orogenic belt. The preserved geology supports a dramatic geodynamic change in the subduction zone process at ca. 1875 Ma, a key driving mechanism for magma and metal mobilization, and was rapidly followed by a large-scale introduction of felsic-intermediate plutons. The overall tectonic setting is partially constrained from new and previously published geochemical data that show that the volcanic and plutonic rocks are high-K calc-alkaline to shoshonitic in nature (e.g., high K 2 O, Th/Yb, and Ce/P 2 0 5 ). They also have suprasubduction-zone geochemical signatures, including primitive mantle normalized positive Th and negative Nb, P, and Ti anomalies. The data support the primary melts were derived from a GLOSS-modified mantle wedge. Three-dimensional rendering of geophysical datasets suggest that two (of four) preserved surfaces within the upper mantle lithosphere, at 70 to 120 km depths, represent frozen, subducted oceanic slabs, and likely were the drivers for the bulk of Hottah and Great Bear arc magmatism. The older slab is northwest-striking and dips 12⁰ to 15⁰ northeast, whereas the younger is deeper and north-striking, dipping 13⁰ east. The geometry of the surfaces are comparable with 4D modeling, where a subduction zone is temporarily shut down due to plateau collision, and then steps oceanward and re-initiates; there is no need for polarity reversal of the subduction system. This new geometry and the related inferences about process should be the focus of future research in the region, but for the time-being it can be stated that these subduction and collisional processes were the first order control on lithospheric evolution, and therefore metallic mineralization. Overall, the Great Bear magmatic zone IOCG and related mineralization is not comparable to other Proterozoic IOCG belts, such as those in Australia. However, the complexity of mineralization styles, the spatial-temporal relationship between IOA and IOCG mineralization, the suprasubduction zone environment, and a major change in tectonic regime are features similar to Andean-type IOCG mineralization, as well as Cordilleran alkali porphyry Cu-A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT3 Au deposits. This further establishes the linkages between subduction zone processes and IOCG formation, as well as relationships in the IOCG-porphyry deposit continuum model.

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Section: Accepted M Manuscriptcontrasting

confidence: 48%

Section: Accepted M Manuscriptmentioning

confidence: 99%

Section: Accepted M Manuscriptmentioning

confidence: 99%

Section: Accepted M Manuscriptmentioning

confidence: 99%

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A Paleoproterozoic Andean-type iron oxide copper-gold environment, the Great Bear magmatic zone, Northwest Canada

Ootes

Snyder

Davis

et al. 2017

Ore Geology Reviews

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“…Partial melting of subduction-modified upper mantle sources beneath Lihir Island was probably triggered by adiabatic decompression melting along deep-seated extensional structures either related to the back-arc rifting of the Manus basin (Taylor 1979) or, more likely, to a north-trending flexure and a resulting slab tear in the subducting Solomon plate (Müller et al 2002b). Slab tears may play a dominant role in the formation of porphyry copper-gold deposits globally (Logan and Mihalynuk 2014). Abundant north-trending structures have been mapped in the open pit of the Ladolam gold mine and they are referred to as Letomazien structures by Corbett (1999).…”

Section: Erection Of Database Gold1mentioning

confidence: 99%

Direct Associations Between Potassic Igneous Rocks and Gold-Copper Deposits in Volcanic Arcs

Müller¹,

Groves²

2015

Potassic Igneous Rocks and Associated Gold-Copper Mineralization

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Geophysical investigation and reconstruction of lithospheric structure and its control on geology, structure, and mineralization in the Cordillera of northern Canada and eastern Alaska

Hayward

2015

Tectonics

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A reconstruction of the Tintina fault is applied to regional geophysical and topographic data, facilitating the definition of west trending lineaments within the lower crust and/or mantle lithosphere, oblique to the NW trending structure of the Cordilleran terranes. The lineaments, which exhibit a range of geophysical and geological signatures, are interpreted to be related to the Liard transfer zone, continuous to the Denali fault, that divided lower and upper plates during late Proterozoic-Cambrian rifting of the Laurentian margin. Three-dimensional gravity models show a density increase in the lower crust and mantle lithosphere to the north. The transfer zone also divides bimodal mantle xenolith suites to the south from unimodal suites to the north. These conclusions suggest that extended North American basement, related to Laurentian margin rifting that would have brought mantle lithosphere rocks to a shallow depth, continuously underlies a thin carapace of accreted terranes in western Yukon and eastern Alaska. The interpreted continuity of North American basement reaffirms that if oroclinal bending of the Intermontane terranes occurred, then it was prior to its emplacement upon the rifted basement. Examination of the spatial relationships between mineral occurrences and postaccretionary, Cretaceous lithospheric lineaments, from their manifestation in geophysical, geological, and topographic data, suggest that the late Proterozoic lineaments influenced Mesozoic mineralization through influence on the development of the shallow crustal structure, intrusion, and exhumation and erosion.

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Tectonic Controls on Early Mesozoic Paired Alkaline Porphyry Deposit Belts (Cu-Au Ag-Pt-Pd-Mo) Within the Canadian Cordillera

Cited by 83 publications

References 103 publications

A Paleoproterozoic Andean-type iron oxide copper-gold environment, the Great Bear magmatic zone, Northwest Canada

A Paleoproterozoic Andean-type iron oxide copper-gold environment, the Great Bear magmatic zone, Northwest Canada

Direct Associations Between Potassic Igneous Rocks and Gold-Copper Deposits in Volcanic Arcs

Geophysical investigation and reconstruction of lithospheric structure and its control on geology, structure, and mineralization in the Cordillera of northern Canada and eastern Alaska

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