Canadian Journal of Earth Sciences最新文献

Crustal Melting Recorded by Dykes along the Gold-bearing Melanson Brook Fault, Northern New Brunswick Appalachians 新不伦瑞克阿巴拉契亚山脉北部梅兰松溪含金断层沿线堤坝记录的地壳融化过程

Canadian Journal of Earth Sciences Pub Date : 2024-08-08 DOI: 10.1139/cjes-2024-0034

A. Bustard, David R. Lentz, James A Walker, Chris R. M. McFarlane

{"title":"Crustal Melting Recorded by Dykes along the Gold-bearing Melanson Brook Fault, Northern New Brunswick Appalachians","authors":"A. Bustard, David R. Lentz, James A Walker, Chris R. M. McFarlane","doi":"10.1139/cjes-2024-0034","DOIUrl":"https://doi.org/10.1139/cjes-2024-0034","url":null,"abstract":"Dykes intruding along the Melanson Brook Fault record two magmatic episodes in northern New Brunswick. Dykes at the South Gold Zone of the Elmtree gold deposit are aphanitic and magnesian-calcic, whereas those at Ellis Brook (2.5 km to the west) are ilmenite-series and weakly peraluminous with hornblende- and plagioclase-porphyritic phases. Elevated 147Sm/44Nd generated by partial melting, titanium depletion, absence of rare earth element fractionation, and trondhjemite-like compositions indicate the South Gold Zone dykes were sourced from low-volume fluid fluxed melting of gabbroic crust. A Sm-Nd depleted model mantle age of 1.1 Ga for the Ellis Brook dykes suggests that they were sourced from melting of Ganderian crustal rocks rather than the sinking Acadian slab. 143Nd/144Nd evolution curves for the South Gold Zone dykes intersect that of the Ellis Brook dykes at 432 Ma and 427 Ma. This suggests that the magma from which the South Gold Zone dykes crystallized was extracted from a similar source area as the magma that generated the Ellis Brook dykes. Evidence of fluid exsolution in the Ellis Brook dykes indicates they could be a potential source for reduced intrusion-related gold mineralization. The Ellis Brook dykes yielded a U-Pb zircon age of 391 ± 5 Ma, which is consistent with the timing of oceanic slab break-off at the end of the Acadian orogenic cycle. Extraction of South Gold Zone magma occurred up to 40 Myr earlier, likely during the Salinic orogenic cycle.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"107 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-08-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141926856","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The volcanic architecture and tectono-magmatic framework of the Mount Grace carbonatites, southeastern Canadian Cordillera 加拿大科迪勒拉山系东南部格雷斯山碳酸盐岩的火山结构和构造-岩浆框架

Canadian Journal of Earth Sciences Pub Date : 2024-07-13 DOI: 10.1139/cjes-2024-0001

Lindsey Abdale, James Kelly Russell, Lee A. Groat

{"title":"The volcanic architecture and tectono-magmatic framework of the Mount Grace carbonatites, southeastern Canadian Cordillera","authors":"Lindsey Abdale, James Kelly Russell, Lee A. Groat","doi":"10.1139/cjes-2024-0001","DOIUrl":"https://doi.org/10.1139/cjes-2024-0001","url":null,"abstract":"The Mount Grace metamorphosed carbonatites (Late Devonian) outcrop as thin (0.5 to 4 m), laterally discontinuous, strata-bound mappable lenses within the Monashee complex of the southeastern Canadian Cordillera. The host stratigraphic sequence (Monashee cover gneiss) was metamorphosed and deformed in the Late Cretaceous to early Eocene followed immediately by exhumation of the Frenchman Cap and Thor Odin domes. We present seven stratigraphic logs for Mount Grace carbonatites including new and previously described outcroppings spanning ~30 km. The Mount Grace carbonatite units were deposited regionally within or near the top of a shallow marine sedimentary sequence within miogeoclinal strata of the western margin of paleo North America (Laurentia). The distribution of the Mount Grace carbonatite lithofacies and the preserved depositional structures and textures suggest these are pyroclastic deposits resulting from phreatomagmatic eruptions. Our new data enhance the volcanological story with an eruption scenario involving phreatomagmatic reactions and deposition from pyroclastic density currents, sourced from multiple centres within a field of monogenetic maar volcanoes. The distribution of the Mount Grace carbonatites parallel to the western margin of the paleo-North American continent correlates well with regional Late Devonian alkaline magmatism associated with development of an extensional back-arc basin.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"58 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141651929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Holocene to Modern Fraser River Delta, Canada: Geological History, Processes, Deposits, Natural Hazards, and Coastal Management 加拿大全新世至现代弗雷泽河三角洲：地质历史、过程、沉积、自然灾害和海岸管理

Canadian Journal of Earth Sciences Pub Date : 2024-07-08 DOI: 10.1139/cjes-2024-0041

A. L. La Croix, S. Dashtgard, PR Hill, K. Ayranci, John J. Clague

{"title":"The Holocene to Modern Fraser River Delta, Canada: Geological History, Processes, Deposits, Natural Hazards, and Coastal Management","authors":"A. L. La Croix, S. Dashtgard, PR Hill, K. Ayranci, John J. Clague","doi":"10.1139/cjes-2024-0041","DOIUrl":"https://doi.org/10.1139/cjes-2024-0041","url":null,"abstract":"The Fraser River Delta (FRD) is a large sedimentary system and home to Metro Vancouver, situated within the unceded territories of several First Nations. This review provides an overview of the geological evolution of the FRD, connecting hydrodynamic processes with sedimentary deposits across its diverse environments, from the river to the delta slope. The study emphasizes the implications of sedimentation and delta evolution for natural hazards and coastal/delta management, pinpointing knowledge gaps. Comprising four main zones – river, delta plain, tidal flats, and delta slope – the FRD is subject to several natural hazards including subsidence, flooding, earthquakes, liquefaction, and tsunamis. The delta plain, bordering the Fraser River’s distributary channels, hosts tidal marshes and flats, including both active and abandoned areas. Active tidal flats like Roberts Bank and Sturgeon Bank receive sediment directly from the Fraser River, while abandoned tidal flats, like those at Boundary Bay and Mud Bay, no longer receive sediment. The tidal flats transition into the delta slope, characterized by sand in the south and mud in the north of the Main Channel. The FRD's susceptibility to hazards necessitates protective measures, with approximately 250 km of dykes shielding the delta plain from river floods and storm surges. Subsidence amplifies the impact of rising sea levels. Earthquakes in the region can induce tsunamis, submarine slope failures, and liquefaction of delta sediments, emphasizing the importance of incorporating sedimentation patterns and delta evolution into management strategies for sustainable urban development, habitat restoration, and coastal defence initiatives.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":" 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141668997","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Devonian plutons in the eastern Meguma terrane, Nova Scotia, Canada: zircon U-Pb, Lu-Hf and O isotopic compositions, age, and petrogenetic implications 加拿大新斯科舍省东部梅古玛地层中的泥盆纪块岩：锆石U-Pb、Lu-Hf和O同位素组成、年龄及岩石成因学意义

Canadian Journal of Earth Sciences Pub Date : 2024-07-05 DOI: 10.1139/cjes-2024-0023

D. Archibald, S. Barr, C. White, Shae J. Nickerson, R. Stern, Yan Luo, Graham D. Pearson

{"title":"Devonian plutons in the eastern Meguma terrane, Nova Scotia, Canada: zircon U-Pb, Lu-Hf and O isotopic compositions, age, and petrogenetic implications","authors":"D. Archibald, S. Barr, C. White, Shae J. Nickerson, R. Stern, Yan Luo, Graham D. Pearson","doi":"10.1139/cjes-2024-0023","DOIUrl":"https://doi.org/10.1139/cjes-2024-0023","url":null,"abstract":"Abundant granitic plutons intruded the eastern Meguma terrane of Nova Scotia in the middle- to late Devonian. Less voluminous diorite-tonalite and gabbro intrusions are associated with the granitic plutons along the northern margin of the terrane adjacent to the Cobequid-Chedabucto fault zone. All plutons contain metasedimentary xenoliths, and the mafic plutons show magma mingling textures with their adjacent granitic plutons. New U-Pb zircon data from autocrystic zircon in 13 samples indicate coeval emplacement of mafic and granitic plutons between ca. 382 and 368 Ma. However, the zircon grains contain numerous inherited domains that range in age from Palaeoproterozoic to Devonian. These inherited ages correspond to detrital zircon U-Pb dates from the Cambrian to Ordovician metasedimentary host rocks. Zircon oxygen isotopic data (δ18O) are between +7.4 ± 0.2 ‰ and +9.3 ± 0.3 ‰ indicating significant involvement of the crust as the magma source or contaminant. If the high δ18Ozrc values are a result of contamination, the contaminant was likely the metasedimentary rocks of the Meguma terrane. Hafnium isotopic data from autocrystic zircon have εHf(t) between -6.0 ± 1.5 and +2.1 ± 2.5. The new zircon U-Pb, O and Hf isotopic data from plutons in the eastern Meguma terrane are indistinguishable from published data from the South Mountain Batholith. These data suggest that Devonian magmatism in the Meguma terrane post-dated or was coeval with the orogenic event that caused folding and regional metamorphism, involved the same magma source and/or contaminants throughout the terrane, and did not involve Avalonian crust.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":" 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141673857","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Upper Triassic igneous rocks of the southern Kenai Peninsula, Alaska – prelude to Early Jurassic subduction along the western Wrangellia composite terrane margin 阿拉斯加基奈半岛南部的上三叠纪火成岩--侏罗纪早期沿西部弗兰盖利亚复合地层边缘俯冲的前奏

Canadian Journal of Earth Sciences Pub Date : 2024-06-14 DOI: 10.1139/cjes-2024-0009

Travis Hudson, Frederic H. Wilson, Paul B. O'Sullivan

{"title":"Upper Triassic igneous rocks of the southern Kenai Peninsula, Alaska – prelude to Early Jurassic subduction along the western Wrangellia composite terrane margin","authors":"Travis Hudson, Frederic H. Wilson, Paul B. O'Sullivan","doi":"10.1139/cjes-2024-0009","DOIUrl":"https://doi.org/10.1139/cjes-2024-0009","url":null,"abstract":"New U-Pb zircon geochronology identifies a latest Triassic (ca 214-201 Ma) igneous suite of tuff, hypabyssal dikes, and a pluton on the southern Kenai Peninsula, Alaska. The igneous suite was emplaced within Upper Triassic sedimentary rocks along the southern margin of Western Wrangellia, the western-most fragment of the Wrangellia composite terrane. The igneous rocks range from mafic (50.6% SiO2) to felsic (78.3% SiO2), characteristically have less than 1.55% K2O, and generally have low trace element abundances. The tonalitic and trondhjemitic magmas were largely sourced in mafic-rich lower crust and incompletely assimilated quartz and other mineral xenocrysts are common. Fractionation involving plagioclase and amphibole is indicated for some magmas and composite intrusions and igneous xenoliths indicate magma mixing was possible. Paleozoic and Precambrian inherited zircons and initial 87Sr/86Sr (0.704103-0.705609) and 143Nd/144Nd (0.512396-0.512777) ratios indicate that the Western Wrangellia crustal sources are heterogeneous and contain sialic components. The latest Triassic magmatism reflects processes that preceded Early Jurassic subduction along the Wrangellia composite terrane and Pacific Ocean plate boundary. These processes involved heating and melting of mantle lithosphere and lower crust as mantle instabilities accompanied the breaking of the plate boundary linkages. The Late Triassic transition to subduction along the Wrangellia composite terrane margin coincided with the transition to subduction cessation in the Late Triassic arcs of the western Intermontane terranes of Canada. The shift to subduction along the outboard Wrangellia composite terrane margin marks the beginning of the Pacific Ocean-Cordillera plate interactions that came to dominate the tectonic evolution of the northern Cordillera from the Early Jurassic to today.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"6 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141344553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Rheological Bridge Zones: The Initialization of Strain Localization 流变桥区：应变定位的初始化

Canadian Journal of Earth Sciences Pub Date : 2024-06-12 DOI: 10.1139/cjes-2023-0132

He Feng, C. Gerbi, Scott E Johnson, A. Cruz‐Uribe, Martin G. Yates

{"title":"Rheological Bridge Zones: The Initialization of Strain Localization","authors":"He Feng, C. Gerbi, Scott E Johnson, A. Cruz‐Uribe, Martin G. Yates","doi":"10.1139/cjes-2023-0132","DOIUrl":"https://doi.org/10.1139/cjes-2023-0132","url":null,"abstract":"Strain localization occurs across the crust in both brittle and viscous regimes, but the exact causes remain debated. Natural rock observations suggest that changes in phase properties (such as physical properties, phase distribution, and grain geometry) are more influential in weakening than variations in stress and temperature. Investigating the early stages of strain accumulation in various pressure-temperature conditions leads to a better understanding of these causes. Our study focuses on three weakly deformed rocks showing zones of localization on a millimeter or smaller scale, which we term “bridge zones”. These localized zones appear to mechanically connect weak domains and typically exhibit finer grain sizes within a narrow band. Importantly, these zones occur in less deformed rocks from the margins of shear zones. They result from both in-situ grain size reduction and chemical processes leading to phase mixing or element mobility on a limited spatial scale. Numerical modeling aligns high-stress areas with these zones, supporting their impact on reducing rock strength. We propose a conceptual model linking far-field loading to microscale changes in developing these zones. Characterization of bridge zones aids in elucidating the microstructural processes driving deformation localization, which is fundamental for plate tectonics, metamorphism, seismicity, and other lithospheric processes. This research reveals microscale mechanisms driving weak domain development, improving our knowledge of rheological changes and laying the groundwork for predictive models regarding strength evolution in the lithosphere.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"17 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141354132","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

The Ottawa River Gneiss Complex revisited: definition of the metamorphic core and detachment zone of a large Grenvillian metamorphic core complex 渥太华河片麻岩复合体再探：大型格林维利变质岩核心复合体的变质岩核心和脱离带的定义

Canadian Journal of Earth Sciences Pub Date : 2024-06-11 DOI: 10.1139/cjes-2023-0060

T. Rivers, W. M. Schwerdtner

{"title":"The Ottawa River Gneiss Complex revisited: definition of the metamorphic core and detachment zone of a large Grenvillian metamorphic core complex","authors":"T. Rivers, W. M. Schwerdtner","doi":"10.1139/cjes-2023-0060","DOIUrl":"https://doi.org/10.1139/cjes-2023-0060","url":null,"abstract":"Using new and published data, we synthesize the tectonic evolution of the Ottawa River Gneiss Complex (ORGC), the metamorphic core and detachment zone of a large mid- to late-Ottawan metamorphic core complex in the western Grenville Province. Field and petrologic data indicative of retrogression and exhumation, combined with maps and schematic crustal-scale sections, are used to document spatial and temporal relationships of multi-scale structures developed during its formation, of which the largest, termed mega-cross-folds and megaboudins, occur within and define the detachment zone. Mega-cross-folds, orogen-normal structures up to 70 km in length with coaxial constrictional fabrics in their hinge-lines, formed in a single phase of deformation during retrogression and exhumation. A cluster of asymmetric megaboudins, individually from 10-50 km long with granulite-facies cores and high-strain amphibolite-facies rims, similarly formed during syntectonic retrogression and exhumation of granulite-facies precursors. We argue the mega-cross-folds developed in a regime of regional transtension, whereas the megaboudin cluster formed by extensional inversion of an anastomosing early-Ottawan thrust system, with the strain patterns of both suggesting the detachment zone was the site of intense ductile flow between the stronger metamorphic core and cover. Comparison of these results with generic numerical models of extensional collapse of overthickened continental crust suggests the first-order tectonometamorphic features of the ORGC developed during necking of the upper crust and associated large-scale extensional flow of the mid and lower crust into the domiform necked region during collapse of the overthickened early-Ottawan thrust stack.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"47 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141355294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Tonian rift successions in Newfoundland, Canada: A window to late tectonic events in the Mesoproterozoic Laurentian margin 加拿大纽芬兰的托尼断裂演替：中新生代劳伦大陆边缘晚期构造事件的窗口

Canadian Journal of Earth Sciences Pub Date : 2024-06-05 DOI: 10.1139/cjes-2024-0007

Susan Strowbridge, G. Dunning, A. Indares, G. Jenner

{"title":"Tonian rift successions in Newfoundland, Canada: A window to late tectonic events in the Mesoproterozoic Laurentian margin","authors":"Susan Strowbridge, G. Dunning, A. Indares, G. Jenner","doi":"10.1139/cjes-2024-0007","DOIUrl":"https://doi.org/10.1139/cjes-2024-0007","url":null,"abstract":"Basement rocks in the Humber terrane of the Appalachian Orogen record the last stages in the history of the Mesoproterozoic Laurentian margin in Canada. These stages were revealed by recent work in the East Pond Metamorphic Suite on the western Baie Verte Peninsula, Newfoundland, where two Tonian bimodal volcaniclastic-sedimentary successions were recognized (Pine Pond successions). The older, ca. 980 Ma succession contains detrital igneous zircon and titanite (ca. 1160‒1057 Ma) presumably derived from the Mesoproterozoic Laurentian margin, while the younger, ca. 950 Ma succession, contains 980 Ma detrital igneous zircon and titanite. Although metamorphosed to eclogite facies during the assembly of the Appalachian Orogen, the successions preserve protolith features and geochemical data that indicate melt likely originated in an extensional setting. The new ages, integrated with geochemical and Sm–Nd isotopic data suggest that the felsic volcaniclastic units of the Pine Pond successions are related to 975–950 Ma granitic plutons in the Pinware terrane of the eastern Grenville Province, in southeastern Labrador. These new data solidify a previous interpretation that the Pine Pond successions were deposited at the continental apex of the Asgard Sea and that the Pinware terrane intrusions are a part of this event. Furthermore, these new Tonian ages for rift-related strata call into question the interpretation of Ediacaran depositional ages for clastic sequences in the northern Appalachian Orogen, with youngest detrital zircons that are Tonian, and show that the tectonic evolution of the Mesoproterozoic Laurentian margin in Canada is more complex than previously known.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"90 2","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141384956","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Geochronology of the Mines Gaspé porphyry deposit, Québec, Canada 加拿大魁北克 Mines Gaspé 斑岩矿床的地质年代学

Canadian Journal of Earth Sciences Pub Date : 2024-06-03 DOI: 10.1139/cjes-2024-0013

Mitch Marcelissen, P. Hollings, David R. Cooke, Michael J. Baker, Ivan Belousov, Evan Orovan, Richard M. Friedman

{"title":"Geochronology of the Mines Gaspé porphyry deposit, Québec, Canada","authors":"Mitch Marcelissen, P. Hollings, David R. Cooke, Michael J. Baker, Ivan Belousov, Evan Orovan, Richard M. Friedman","doi":"10.1139/cjes-2024-0013","DOIUrl":"https://doi.org/10.1139/cjes-2024-0013","url":null,"abstract":"The Mines Gaspé area hosts multiple Cu-Mo skarn and porphyry orebodies near the town of Murdochville in the northeastern part of the Gaspé Peninsula, Québec. The orebodies occur within overlapping alteration aureoles in calcareous Lower Devonian sedimentary rocks. The strata are intruded by numerous multiphase porphyry sills, dykes, and plugs of Devonian age. The Porphyry Mountain intrusion and a sill in the Copper Mountain pit have been dated at 378.80 ± 0.37 Ma and 377.60 ± 0.45 Ma, respectively, refining the results of previous studies, and demonstrating Porphyry Mountain intrusion emplacement at least 0.38 m.y. before Copper Mountain. Circa 392 Ma inherited zircon grains at Mines Gaspé suggest an early phase of magmatism that produced the extensive skarn alteration aureoles throughout the Gaspé Peninsula at sites like Mines Gaspé and the nearby McGerrigle Complex, followed by significantly later ( > 10 m.y.) porphyritic intrusions and associated mineralization that added to existing skarn resources. Epidote at both Mines Gaspé and Sullipek occur as disseminated/granular crystals within the host groundmass and as larger crystals within veinlets or veinlet halos in metasomatised sedimentary rocks. Epidote ages suggest that there are several different propylitic hydrothermal events within the region at Mines Gaspé and Sullipek, which combined with new zircon U-Pb ages implies a prolonged and complex history of propylitic alteration within Gaspésie.","PeriodicalId":503418,"journal":{"name":"Canadian Journal of Earth Sciences","volume":"32 24","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141273022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

New Late Cretaceous (Cenomanian) fossil mayfly nymphs (Oligoneuriidae, Heptageniidae, Hexagenitidae) from the Redmond Formation, Labrador, Canada 加拿大拉布拉多雷德蒙德地层新发现的晚白垩世（仙人掌纪）蜉蝣若虫化石（Oligoneuriidae、Heptageniidae、Hexagenitidae

Canadian Journal of Earth Sciences Pub Date : 2024-06-01 DOI: 10.1139/cjes-2023-0133

André S. Mueller, Alexandre V. Demers‐Potvin

引用次数: 0