Geoscience Canada最新文献

{"title":"Heritage Stone 9. Tyndall Stone, Canada’s First Global Heritage Stone Resource: Geology, Paleontology, Ichnology and Architecture","authors":"B. Pratt, G. Young","doi":"10.12789/geocanj.2023.50.196","DOIUrl":"https://doi.org/10.12789/geocanj.2023.50.196","url":null,"abstract":"Tyndall Stone is a distinctively mottled and strikingly fossiliferous dolomitic limestone that has been widely used for over a century in Canada, especially in the Prairie Provinces. It comprises 6–8 m within the lower part of the 43 m thick Selkirk Member of the Red River Formation, of Late Ordovician (Katian) age. It has been quarried exclusively at Garson, Manitoba, 37 km northeast of Winnipeg, since about 1895, and for the past half-century extraction has been carried out solely by Gillis Quarries Ltd. The upper beds tend to be more buff-coloured than the grey lower beds, as a result of groundwater weathering. Tyndall Stone, mostly with a smooth or sawn finish, has been put to a wide variety of uses, including exterior and interior cladding with coursed and random ashlar, and window casements and doorways. Split face finish and random ashlar using varicoloured blocks split along stylolites have become popular for commercial and residential buildings, respectively. Tyndall Stone lends itself to carving as well, being used in columns, coats of arms and sculptures. Many prominent buildings have been constructed using Tyndall Stone, including the provincial legislative buildings of Saskatchewan and Manitoba, the interior of the Centre Block of the House of Commons in Ottawa, courthouses, land titles buildings, post offices and other public buildings, along with train stations, banks, churches, department stores, museums, office buildings and university buildings. These exhibit a variety of architectural styles, from Beaux Arts to Art Deco, Châteauesque to Brutalist. The Canadian Museum of History and the Canadian Museum for Human Rights are two notable Expressionist buildings.   The lower Selkirk Member is massive and consists of bioturbated, bioclastic wackestone to packstone, rich in crinoid ossicles. It was deposited in a low-energy marine environment within the photic zone, on the present-day eastern side of the shallow Williston Basin, which was part of the vast equatorial epicontinental sea that covered much of Laurentia at the time. Scattered thin bioclastic grainstone lenses record episodic, higher energy events. Tyndall Stone is spectacularly fossiliferous, and slabs bearing fossils have become increasingly popular. The most common macrofossils are receptaculitids, followed by corals, stromatoporoid sponges, nautiloid cephalopods, and gastropods. The relative abundance of the macrofossils varies stratigraphically, suggesting that subtle environmental changes took place over time.    The distinctive mottles—‘tapestry’ in the trade—have been regarded as dolomitized burrows assigned to Thalassinoides and long thought to have been networks of galleries likely made by arthropods. In detail, however, the bioclastic muddy sediment underwent a protracted history of bioturbation, and the large burrows were mostly horizontal back-filled features that were never empty. They can be assigned to Planolites. The matrix and the sediment filling them wer","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47473723","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Lewisian: Britain’s Oldest Rocks","authors":"B. Ryan","doi":"10.12789/geocanj.2023.50.195","DOIUrl":"https://doi.org/10.12789/geocanj.2023.50.195","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47820064","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Sudbury 2023: GAC–MAC–SGA Joint Annual Meeting Field Trips","authors":"B. Lafrance","doi":"10.12789/geocanj.2023.50.193","DOIUrl":"https://doi.org/10.12789/geocanj.2023.50.193","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43538228","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Tuzo: The Unlikely Revolutionary of Plate Tectonics","authors":"A. Hynes","doi":"10.12789/geocanj.2023.50.194","DOIUrl":"https://doi.org/10.12789/geocanj.2023.50.194","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-03-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46334736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"in the Persian Gulf","authors":"Mr J W Jackson","doi":"10.2307/j.ctt1r33pxt.4","DOIUrl":"https://doi.org/10.2307/j.ctt1r33pxt.4","url":null,"abstract":"Some months ago I received from Dr. J. Cosmo Melvill a small box containing brachiopods from the Persian Gulf. These had been obtained by Mr. F. W. Townsend in the course of his dredgings for Mollusca in that region. The locality on the box containing the specimens is Dabai, which lies within the Persian Gulf on the N.W. coast of Oman. Its exact position is on the west side of the peninsula of Ruus El Jibal, on what is known as the Pirate Coast. Unfortunately, no particulars as to depth etc. accompanied the specimens. With the exception of the Mollusca and some Madreporarian corals very little appears to be known of the fauna of the Persian Gulf. The Mollusca have been ably dealt with in a series of papers by Messrs. Melvill and Standen*, and the corals were described in 1911 in a paper by Miss Ruth Harrison \"f, to which Professor S. J. Hickson added some further notes J. The discovery of Brachiopoda in the Persian Gulf is of very great interest, not only from the fact that these specimens are the first of the class to be recorded from this region — i. e., the N.W. corner of the Indian Ocean (including the Persian Gulf, Gulf of Oman, and Arabian Sea), — but more especially from the important bearing of these specimens on the subject of the relation of the fauna of the Persian Gulf to that of the Mediterranean Sea and Atlantic Ocean. Four specimens only were present in the box, one of which is a Terebratulina, the other three belonging to the genus Muhlfeldtia. All are dead empty shells, and a small quantity of greyish marl was present in the interior of one or two. Unfortunately , in the case of the Terebratulina, the brachidium, or loop, is broken, but the shell is otherwise quite perfect, both valves being present. In form and size it is very like a specimen of Terebratulina caput-serpentis figured by Fischer and Oehlert from the ' Talisman ' Expedition in the Lusitanian Subregion §. It has the same general outline and is cut off","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"35 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68720516","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Last Billion Years: A Geological History of the Maritime Provinces of Canada","authors":"Tracy J. Webb","doi":"10.12789/geocanj.2022.49.192","DOIUrl":"https://doi.org/10.12789/geocanj.2022.49.192","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46631019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Logan Medallist 7. Appinite Complexes, Granitoid Batholiths and Crustal Growth: A Conceptual Model","authors":"J. Murphy, W. J. Collins, D. Archibald","doi":"10.12789/geocanj.2022.49.191","DOIUrl":"https://doi.org/10.12789/geocanj.2022.49.191","url":null,"abstract":"Appinite bodies are a suite of plutonic rocks, ranging from ultramafic to felsic in composition, that are characterized by idiomorphic hornblende as the dominant mafic mineral in all lithologies and by spectacularly diverse textures, including planar and linear magmatic fabrics, mafic pegmatites and widespread evidence of mingling between coeval mafic and felsic compositions. These features suggest crystallization from anomalously water-rich magma which, according to limited isotopic studies, has both mantle and meteoric components. Appinite bodies typically occur as small (~2 km diameter) complexes emplaced along the periphery of granitoid plutons and commonly adjacent to major deep crustal faults, which they preferentially exploit during their ascent. Several studies emphasize the relationship between intrusion of appinite, granitoid plutonism and termination of subduction. However, recent geochronological data suggest a more long-lived genetic relationship between appinite and granitoid magma generation and subduction.Appinite may represent aliquots of hydrous basaltic magma derived from variably fractionated mafic underplates that were originally emplaced during protracted subduction adjacent to the Moho, triggering generation of voluminous granitoid magma by partial melting in the overlying MASH zone. Hydrous mafic magma from this underplate may have ascended, accumulated, and differentiated at mid-to-upper crustal levels (ca. 3–6 kbar, 15 km depth) and crystallized under water-saturated conditions. The granitoid magma was emplaced in pulses when transient stresses activated favourably oriented structures which became conduits for magma transport. The ascent of late mafic magma, however, is impeded by the rheological barriers created by the structurally overlying granitoid magma bodies. Magma that forms appinite complexes evaded those rheological barriers because it preferentially exploited the deep crustal faults that bounded the plutonic system. In this scenario, appinite complexes may be a direct connection to the mafic underplate and so its most mafic components may provide insights into processes that generate granitoid batholiths and, more generally, into crustal growth in arc systems.","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41402126","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"MINING COUNTRY — A History of Canada’s Mines and Miners","authors":"P. Dimmell","doi":"10.12789/geocanj.2022.49.190","DOIUrl":"https://doi.org/10.12789/geocanj.2022.49.190","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41838170","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Looking Back to Move Forward: Why Scientific Societies Should Contribute to Making our Science an Equitable, Safe, and Inclusive Space","authors":"De Wet van Rooyen","doi":"10.12789/geocanj.2022.49.187","DOIUrl":"https://doi.org/10.12789/geocanj.2022.49.187","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45271241","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"GAC-MAC-IAH-CNC-CSPG 2022 Halifax Meeting: Abstracts, Volume 45","authors":"Sandra Barr","doi":"10.12789/geocanj.2022.49.188","DOIUrl":"https://doi.org/10.12789/geocanj.2022.49.188","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-07-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43907025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}