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Geology and Wine 14. Terroir of Historic Wollersheim Winery, Lake Wisconsin American Viticultural Area 地质学与葡萄酒历史悠久的沃勒斯海姆酒庄,威斯康星湖美国葡萄种植区的风土
4区 地球科学
Geoscience Canada Pub Date : 2016-12-15 DOI: 10.12789/geocanj.2016.43.107
S. Karakis, B. Cameron, W. Kean
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引用次数: 0
Commitment, Collaboration and Communication: The Backbones of Geoscience 承诺、合作和沟通:地球科学的支柱
4区 地球科学
Geoscience Canada Pub Date : 2016-12-15 DOI: 10.12789/GEOCANJ.2016.43.106
Victoria Yehl
{"title":"Commitment, Collaboration and Communication: The Backbones of Geoscience","authors":"Victoria Yehl","doi":"10.12789/GEOCANJ.2016.43.106","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.106","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"227-230"},"PeriodicalIF":0.0,"publicationDate":"2016-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817605","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}
引用次数: 1
Did the Atlantic close and then reopen?: A commentary 大西洋关闭后又重新开放了吗?:评论
4区 地球科学
Geoscience Canada Pub Date : 2016-12-15 DOI: 10.12789/GEOCANJ.2016.43.109
H. Williams
{"title":"Did the Atlantic close and then reopen?: A commentary","authors":"H. Williams","doi":"10.12789/GEOCANJ.2016.43.109","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.109","url":null,"abstract":"Tuzo Wilson’s 1966 Nature paper entitled “Did the Atlantic close and then re-open?” is truly the major turning point in the history of ideas on the evolution of the Appalachian Orogen. For a hundred years, the Appalachian Orogen was the type geosyncline, and Appalachian evolution was viewed in fixist models of geosynclinal development. Contrasting faunal realms were always enigmatic and never properly explained by notions of land barriers. Equally enigmatic was the symmetry and two-sided nature of the Newfoundland cross-section that refuted the fixist idea that continents grew like trees by the outward addition of asymmetric peripheral rings. The Wilson Cycle of closing a proto-Atlantic Ocean, then re-opening the Atlantic Ocean provided an elegant and simple solution to these enigmas. Wilson realized that island arcs existed on the North American side of the proto-Atlantic, such as the present Notre Dame Subzone in Newfoundland, and that the major faunal boundary lay to the east of these volcanic rocks. He also realized that the early Paleozoic continents may have touched in the middle Ordovician, “...for thereafter the distinction between the Atlantic and Pacific faunal realms ceases to be marked.” One continent encroaching upon another in the middle and late Ordovician explained the former borderland concept of Charles Schuchert and Marshall Kay. Likewise, Kay’s island arcs were most in evidence during the early Ordovician, the time of major proto-Atlantic closing. Wilson also recognized irregularities in ocean closing, which occurs first at promontories, then at re-entrants, with resulting clastic wedges, and an overall change from early Paleozoic marine conditions to middle and late Paleozoic terrestrial conditions. The Taconic allochthons were also part of his ocean closing scenario. The proto-Atlantic was completely closed by the end of the Paleozoic, and major spreading of the Atlantic began in the Cretaceous. Wilson then went on to trace the former course of the proto-Atlantic along the length of the Appalachian–Caledonian chain from Spitsbergen to Florida. This is no small task. It is encouraging to see that the contemporary Newfoundland analysis supported his views, and that even Tuzo had trouble finding a suture along the New England segment of the system. Northwest Africa was accommodated with ease as a Hercynian orogenic belt, in some respects symmetrical to the southern Appalachians. An important corollary of the Wilson Cycle is that the assembly and eventual breakup of Pangaea must have been an event of major significance in world geology. This is certainly true in North America, where major orogenesis and accretion in the Cordilleran Orogen on the Pacific Margin corresponds to Atlantic opening. Since the 1966 Wilson paper, we have emerged from fixist geosynclinal models that were entrenched in the literature for 100 years. Still, the Appalachian Orogen is full of surprises and there are many secrets yet to be revealed. As so aptly","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"286"},"PeriodicalIF":0.0,"publicationDate":"2016-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817692","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}
引用次数: 4
The Role of the Ancestral Yellowstone Plume in the Tectonic Evolution of the Western United States 祖先黄石羽流在美国西部构造演化中的作用
4区 地球科学
Geoscience Canada Pub Date : 2016-12-15 DOI: 10.12789/GEOCANJ.2016.43.105
J. Murphy
{"title":"The Role of the Ancestral Yellowstone Plume in the Tectonic Evolution of the Western United States","authors":"J. Murphy","doi":"10.12789/GEOCANJ.2016.43.105","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.105","url":null,"abstract":"Plate reconstructions indicate that if the Yellowstone plume existed prior to 50 Ma, then it would have been overlain by oceanic lithosphere located to the west of the North American plate (NAP). In the context of models supporting long-lived easterly directed subduction of oceanic lithosphere beneath the NAP, the Yellowstone plume would have been progressively overridden by the NAP continental margin since that time, the effects of which should be apparent in the geological record. The role of this ‘ancestral’ Yellowstone plume and its related buoyant swell in influencing the Late Mesozoic–Cenozoic tectonic evolution of the southwestern United States is reviewed in the light of recent field, analytical and geophysical data, constraints provided by more refined paleogeographic constructions, and by insights derived from recent geodynamic modeling of the interaction of a plume and a subduction zone.   Geodynamic models suggesting that the ascent of plumes is either stalled or destroyed at subduction zones have focused attention on the role of gaps or tears in the subducted slab that permit the flow of plume material from the lower to the upper plate during subduction. These models imply that the ascent of plumes may be significantly deflected as plume material migrates from the lower to the upper plate, so that the connection between the hot spot track calculated from plate reconstructions and the manifestations of plume activity in the upper plate may be far more diffuse compared to the more precise relationships in the oceanic domain. Other geodynamic models support the hypothesis that subduction of oceanic plateau material beneath the NAP correlates with the generation of a flat slab, which has long been held to have been a defining characteristic of the Laramide orogeny in the western United States, the dominant Late Mesozoic–Early Cenozoic orogenic episode affecting the NAP.   Over the last 20 years, a growing body of evidence from a variety of approaches suggests that a plume existed between 70 and 50 Ma within the oceanic realm close to the NAP margin in a similar location and with similar vigour to the modern Yellowstone hot spot. If so, interaction of this plume with the margin would have been preceded by that of its buoyant swell and related oceanic plateau, a scenario which could have generated the flat slab subduction that characterizes the Laramide orogeny.   Unless this plume was destroyed by subduction, it would have gone into an incubation period when it was overridden by the North American margin. During this incubation period, plume material could have migrated into the upper plate via slab windows or tears or around the lateral margins of the slab, in a manner consistent with recent laboratory models. The resulting magmatic activity may be located at considerable distance from the calculated hot spot track.   The current distribution of plumes and their buoyant swells suggests that their interaction with subduction zones should ","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"231-250"},"PeriodicalIF":0.0,"publicationDate":"2016-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817600","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}
引用次数: 12
Tuzo Wilson: An Appreciation on the 50th Anniversary of his 1966 Paper 图佐·威尔逊:1966年发表论文50周年纪念
4区 地球科学
Geoscience Canada Pub Date : 2016-12-15 DOI: 10.12789/GEOCANJ.2016.43.108
J. Dewey
{"title":"Tuzo Wilson: An Appreciation on the 50th Anniversary of his 1966 Paper","authors":"J. Dewey","doi":"10.12789/GEOCANJ.2016.43.108","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.108","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"283-285"},"PeriodicalIF":0.0,"publicationDate":"2016-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817680","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}
引用次数: 2
Kingston 2017: GAC–MAC Joint Annual Meeting Field Trips 金士顿2017:GAC-MAC联合年会实地考察
4区 地球科学
Geoscience Canada Pub Date : 2016-12-15 DOI: 10.12789/GEOCANJ.2016.43.110
D. Kellett, L. Godin
{"title":"Kingston 2017: GAC–MAC Joint Annual Meeting Field Trips","authors":"D. Kellett, L. Godin","doi":"10.12789/GEOCANJ.2016.43.110","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.110","url":null,"abstract":"BACK TO WHERE IT BEGAN The Department of Geological Sciences and Geological Engineering of Queen’s University, in Kingston, Ontario, will host the 2017 Annual meeting of the GAC–MAC. The meeting will coincide with the 175 anniversary of the founding of the Geological Survey of Canada, which was established by the legislature of the Province of Canada in 1842, in Kingston, and with Canada’s 150 anniversary celebrations. The local geology surrounding Kingston, commonly called the Limestone City, does not disappoint and multiple field trips associated with the meeting will take advantage of its unique location. Kingston is located at the eastern end of Lake Ontario, where the St. Lawrence River begins, draining the waters of the Great Lakes into the Gulf of St. Lawrence. The transition from lake to river occurs east of Kingston Harbour, where the nearly flat-lying Early Paleozoic limestone, rimming the eastern Lake Ontario basin, border against a NW-SE trending, low ridge of Grenvillian Precambrian basement rocks, locally known as the Frontenac Arch, which connects the southeastern Ontario part of the Canadian Shield with the Adirondack Massif of northern New York State. The crystalline basement rocks form a resistant ridge over which the St. Lawrence River flows northeastward from Lake Ontario, creating the ‘Thousand Islands,’ a well-known tourist and cottage region along the international border that now also includes a National Park. The 2017 Kingston GAC–MAC meeting will provide seven field trip opportunities that span from Proterozoic geology to the present, and cover a wide range of Earth Sciences sub-disciplines, from geomorphology to hydrology, from Quaternary geology to metallogeny, and from tectonics to sedimentology. Trips range in length from one to five days, as homegrown as a day trip touring the local geology highlights of Kingston’s environs, and as far-afield as a five day transect traversing the accreted terranes of the Newfoundland Appalachians. The one-day ‘Bedrock to Beaches’ field trip will take participants from Kingston to Prince Edward County and back. Along the way, participants will track one billion years of evolution of the Kingston region. They will contemplate metasedimentary rocks that were heated, squeezed, and intruded by granite ca. 1170 million years ago, sandstone deposited by rivers and wind ca. 490 million years ago, limestone and shale deposited in tropical seawater ca. 455 million years ago, faults that displaced the limestone perhaps 176 million years ago, drumlins shaped by a continental ice-sheet about 20,000 years ago, a shoreline created by a giant proglacial lake ca. 13,200 years ago, and a thin soil full of frost-heaved limestone nodules that nowadays nourishes many of the best vineyards in ‘the County.’ Another one-day trip will explore local shallow neritic marine carbonate rocks on a tropical Ordovician Earth. Shallow water marine carbonate rocks are beautifully exposed in the Kingston area and many","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"287-289"},"PeriodicalIF":0.0,"publicationDate":"2016-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817764","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}
引用次数: 0
The Metallogeny of Lode Gold Deposits: A Syngenetic Perspective 含矿脉金矿床成矿作用:同生视角
4区 地球科学
Geoscience Canada Pub Date : 2016-12-15 DOI: 10.12789/GEOCANJ.2016.43.112
T. Christie
{"title":"The Metallogeny of Lode Gold Deposits: A Syngenetic Perspective","authors":"T. Christie","doi":"10.12789/GEOCANJ.2016.43.112","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.112","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"291-293"},"PeriodicalIF":0.0,"publicationDate":"2016-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817778","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}
引用次数: 1
Geoscience Medallist 1. Understanding the Holocene Closed-Basin Phases (Lowstands) of the Laurentian Great Lakes and Their Significance 地球科学奖章获得者劳伦斯五大湖全新世闭盆期(低地)的认识及其意义
4区 地球科学
Geoscience Canada Pub Date : 2016-09-30 DOI: 10.12789/GEOCANJ.2016.43.102
C. Lewis
{"title":"Geoscience Medallist 1. Understanding the Holocene Closed-Basin Phases (Lowstands) of the Laurentian Great Lakes and Their Significance","authors":"C. Lewis","doi":"10.12789/GEOCANJ.2016.43.102","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.102","url":null,"abstract":"The Laurentian Great Lakes are a chain of five large water bodies and connecting rivers that constitute the headwaters of the St. Lawrence River. Collectively they form one of the largest reservoirs of surface freshwater on the planet with an aggregate volume of >22,000 km3. Early interpretations of the postglacial lake history implicitly assumed that the Great Lakes always overflowed their outlets. A study of Lake Winnipeg which concluded that lack of water in a dry climate had dried that lake for millennia led to re-evaluation of the Great Lakes water-level history. Using the empirical information of glacioisostatic rebound derived from 14C-dated and uptilted Great Lake paleo-shorelines, a method of computation was developed to test the paradigm of continuous lake overflow. The method evaluated site and outlet uplift independently, and lowlevel indicators such as submerged tree stumps rooted beneath the present Great Lakes were found to be lower than the lowestpossible corresponding basin outlet. Results confirmed the low-level, closed-basin hydrological status of the early Great Lakes. This status is consistent with paleoclimatic inferences of aridity during the early Holocene before establishment of the present patterns of atmospheric circulation which now bring adequate precipitation to maintain the overflowing lakes. In a sense, the early to middle Holocene phase of dry climate and low water levels is a natural experiment to illustrate the sensitivity of the Great Lakes to climate change in this era of global warming, should their climate shift to one much drier than present, or future major diversions of their waters be permitted.RESUMELes Grands Lacs Laurentiens sont une chaine de cinq grandes etendues d’eau connectees par des rivieres, constituant la source du Fleuve St-Laurent. Collectivement, ils forment un des plus grands reservoirs d’eau douce de surface de la planete avec un volume total de plus de >22,000 km3. Les premieresinterpretations de l’histoire postglaciaire des lacs supposaient implicitement que les Grands Lacs debordaient a leurs exutoires. Une etude du Lac Winnipeg, qui concluait qu’un deficit en eau durant un episode de climat aride avait desseche le lac pendant des millenaires dans le passe, a mene a la reevaluation de l’histoire du niveau de l’eau des Grands Lacs. En utilisant des donnees empiriques du relevement glacio-isostatique, derivees de littoral anciens sureleves dates au 14C, une methode de calcul a ete developpee pour tester le paradigme d’unedecharge lacustre continue. La methode a evalue le soulevement des sites et des exutoires independamment, et il a ete constate que les indicateurs de bas niveau tels que des troncs d’arbres submerges, enracines en dessous des Grands Lacs actuels, etaient en fait sous le niveau de l’exutoire correspondant le plus bas. Les resultats confirment le bas niveau et le statut de basin hydrologique ferme des Grand Lacs dans le passe. Ce statut est coherent avec des evidences pal","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"179-197"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817812","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}
引用次数: 9
Rare Earth and Critical Elements in Ore Deposits 稀土和矿床中的关键元素
4区 地球科学
Geoscience Canada Pub Date : 2016-09-30 DOI: 10.12789/geocanj.2016.43.103
A. Kerr
{"title":"Rare Earth and Critical Elements in Ore Deposits","authors":"A. Kerr","doi":"10.12789/geocanj.2016.43.103","DOIUrl":"https://doi.org/10.12789/geocanj.2016.43.103","url":null,"abstract":"","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"223-226"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817916","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}
引用次数: 3
Magmatism and Extension in the Foreland and Near-Trench Region of Collisional and Convergent Tectonic Systems 碰撞与收敛构造体系前陆与近海沟地区的岩浆活动与伸展
4区 地球科学
Geoscience Canada Pub Date : 2016-09-30 DOI: 10.12789/GEOCANJ.2016.43.100
A. Schoonmaker, W. Kidd, Tristan J. Ashcroft
{"title":"Magmatism and Extension in the Foreland and Near-Trench Region of Collisional and Convergent Tectonic Systems","authors":"A. Schoonmaker, W. Kidd, Tristan J. Ashcroft","doi":"10.12789/GEOCANJ.2016.43.100","DOIUrl":"https://doi.org/10.12789/GEOCANJ.2016.43.100","url":null,"abstract":"Foreland magmatism occurs in the lower plate during arc–continent or continent–continent collision, although it is uncommon. Ancient examples are recognized by a stratigraphic section into which mafic lavas and/or shallow sills are emplaced at a level at the top of a passive margin cover sequence, or within the overlying deeper water deposits that include mudrocks and flysch-type turbidites. Extensional structures associated with the emplacement of the volcanic rocks may develop slightly prior to or contemporaneous with the arrival of the approaching thrust front. We have selected twelve examples of magmatism in collisional forelands, modern and ancient, and have compared the tectonic associations of the magmatism with the magmatic geochemistry. Foreland magmatic settings fall into two strikingly distinct geochemical groups: a more enriched alkaline group (Rhine-type) and a more heterogeneous tholeiitic group (Maine-type) that may show traces of prior subduction processes. In the examples where the contemporaneous extensional structures are known, faults and basins develop parallel to the thrust front for the tholeiitic group and have oblique orientations, in several cases at a high angle to the thrust front, for the alkaline group. The geochemical results are quite sufficiently distinct to permit discrimination of these two foreland magmatic rock suites from each other in ancient examples where the foreland setting is clear from geological evidence. However, magmatic products of the same range of compositions can be generated in other tectonic environments (rifts, back-arc basins), so the geochemical characteristics alone are insufficient to identify a foreland basin setting. The alkaline Rhine-type group formed primarily in response to localized upwelling convective activity from the sub-asthenospheric mantle beneath the lower plate during collision while the tholeiitic Maine-type group formed primarily in response to melting of subcontinental asthenospheric mantle during extension of the lower plate by slab pull, and resulting lithospheric detachment. It is possible that there has been a long-term secular decrease in the occurrence of the Maine-type foreland magmatism since the early Proterozoic. RESUME Bien que peu frequent, il arrive qu’un magmatisme d’avantpays se produise dans la plaque inferieure durant une collision arc-continent ou continent-continent. Des exemples anciens ont ete decrits dans une coupe stratigraphique renfermant des laves mafiques et/ou des filons-couches au haut d’une sequence de couverture de marge passive, ou au sein de depots de plus grandes profondeurs comme des boues ou des turbidites de type flysch. Des structures d’etirement associees a la mise en place des roches volcaniques peuvent se developper un peu avant ou en meme temps que l’arrivee du front de chevauchement. Nous avons choisi douze exemples de magmatisme au sein d’avant-pays de collision, modernes et anciens, et nous avons compare les associations tect","PeriodicalId":55106,"journal":{"name":"Geoscience Canada","volume":"43 1","pages":"159-178"},"PeriodicalIF":0.0,"publicationDate":"2016-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"66817281","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}
引用次数: 0
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