The entire Great Lakes watershed drains through Lake Ontario and flows into the St. Lawrence River near Cape Vincent, New York. The St. Lawrence River then flows northeast through Quebec and Ontario and into the large...The entire Great Lakes watershed drains through Lake Ontario and flows into the St. Lawrence River near Cape Vincent, New York. The St. Lawrence River then flows northeast through Quebec and Ontario and into the largest estuary in the world, the Gulf of Saint Lawrence. The St. Lawrence River, between Ontario, Canada and New York, United States is part of the international boundary. The St. Lawrence Seaway permits ocean-going vessels to go from the Great Lakes of North America to the Atlantic Ocean. Navigation of the St. Lawrence was not possible until canals were built around the Lachine Rapids near Montreal. The canals allowed ships to by-passes the rapids and travel into Lake Ontario. In 1954, the United States agreed to joint development of the international sections of the St. Lawrence River. The St. Lawrence Seaway was opened in 1959 and permits ocean-going ships to go all the way to the southwest corner of Lake Superior near Duluth, Minnesota. During WWII, German U-boats sank several merchant marine ships and three Canadian warships in the lower St. Lawrence River, the Strait of Belle Isle, Cabot Strait and the Gulf of Saint Lawrence. The bottom of the St. Lawrence River is littered with the wreckage of these ships and other ships which were lost during storms. The International Joint Commission recommended that the Canada and United States jointly improve navigation on the St. Lawrence River from Lake Ontario to Montreal. This lead to the signing of the St. Lawrence Treaty. Steel companies supported the treaties since the new St. Lawrence Seaway could get Labrador iron ore to the United States mills in the Great Lakes region. The Seaway’s power dams generate 3.5 million kilowatts of electricity which is provided to industry and to thousands of consumers in the New York State, New England and parts of Canada. The electric power generated by the project would be shared equally. This paper highlights how the geological and landscape properties of the St. Lawrence River watershed were responsible for the successful economic development of this important and historically-rich region of North America. Planned economic and urban development of the St. Lawrence River basin by USACE was blocked by the “Save the River” campaign. Environmental challenges include disposal of treated and untreated wastewater, water pollution, and shore erosion, invasive species and flooding.展开更多
The Appalachian orogen in North America is currently considered to be a Paleozoic accretion-type orogenic belt,or a collage,formed by collision of many ancient blocks between Laurentian and Gondwanan margins(Williams,...The Appalachian orogen in North America is currently considered to be a Paleozoic accretion-type orogenic belt,or a collage,formed by collision of many ancient blocks between Laurentian and Gondwanan margins(Williams,1979;Williams et al.,1988;van Staal et al.,2007).Recently,major progress has been made in understanding the characteristics and tectonic evolution of the outboard peri-Laurentian and peri-Gondwanan terranes of the Iapetus Ocean(van Staal et al.,2009,2012).展开更多
纽芬兰-拉布拉多省地处加拿大地盾东缘,成矿条件十分优越,是加拿大重要的镍矿成矿区,矿化类型多样。文章基于前人对该区镍矿床和矿化的研究,从区域成矿地质背景、矿化类型及地质特征、地球物理特征、勘探潜力、勘查态势等等方面进行了...纽芬兰-拉布拉多省地处加拿大地盾东缘,成矿条件十分优越,是加拿大重要的镍矿成矿区,矿化类型多样。文章基于前人对该区镍矿床和矿化的研究,从区域成矿地质背景、矿化类型及地质特征、地球物理特征、勘探潜力、勘查态势等等方面进行了系统分析。拉布拉多地区的镍矿资源主要分布于辉长质—橄长质镁铁质岩石分布区,主要与中元古代侵入的辉长岩、斜长岩、橄长岩、辉石岩有关,或与太古宙超镁铁质变火山岩有关,矿化类型有橄长岩和辉长岩型、辉石岩型、斜长岩型、铁闪长岩型、火山岩(科马提岩)型;Voisey′s Bay Ni-Cu-Co硫化物矿床是拉布拉多地区已发现的大型镍矿床。纽芬兰地区的镍矿资源主要与古生代辉长-闪长质侵入岩、前寒武系镁铁质片麻岩有关,矿化类型主要有辉长岩型、镁铁质片麻岩型、火山热液型。纽芬兰-拉布拉多省的镍矿勘查前景乐观。展开更多
加拿大阿巴拉契亚造山带纽芬兰岛Humber带基底地块属性及地壳生长演化是近年来关注的科学问题,尤其是岛内西南部的Indian Head Range地块,其年龄组成与同位素特征研究对区域基底构造属性划分与对比至关重要。本文对Indian Head Range地...加拿大阿巴拉契亚造山带纽芬兰岛Humber带基底地块属性及地壳生长演化是近年来关注的科学问题,尤其是岛内西南部的Indian Head Range地块,其年龄组成与同位素特征研究对区域基底构造属性划分与对比至关重要。本文对Indian Head Range地块内的二长花岗岩岩体进行了锆石U⁃Pb定年,得到其^(206)Pb/^(238)U加权平均年龄值为1149±4 Ma,代表该岩体的侵位年龄。这一定年结果表明该岩体具有中元古代晚期的年龄,为该地块格林威尔期岩浆事件的存在提供了新的年龄证据。Nd⁃Hf同位素分析结果显示,该二长花岗岩岩体εNd值为-2.3,εHf值介于+1.93~+3.65之间,两阶段Hf模式年龄介于1.84~1.73 Ga之间。结合前人研究,我们认为Humber带内各地块发育约1.5 Ga、1.15 Ga和1.0 Ga的3期花岗质岩浆事件,它们具有相似的Hf模式年龄值,暗示它们均来源于古元古代新生地壳物质的再造。带内格林威尔基底地块均为原地基底,且与劳伦大陆远端东部边缘具有一致的岩浆-构造演化史。以上研究对Humber带内格林威尔基底地块的亲缘性及地壳生长提供新的制约,并为阿巴拉契亚造山带内古老微陆块的溯源对比提供依据。展开更多
文摘The entire Great Lakes watershed drains through Lake Ontario and flows into the St. Lawrence River near Cape Vincent, New York. The St. Lawrence River then flows northeast through Quebec and Ontario and into the largest estuary in the world, the Gulf of Saint Lawrence. The St. Lawrence River, between Ontario, Canada and New York, United States is part of the international boundary. The St. Lawrence Seaway permits ocean-going vessels to go from the Great Lakes of North America to the Atlantic Ocean. Navigation of the St. Lawrence was not possible until canals were built around the Lachine Rapids near Montreal. The canals allowed ships to by-passes the rapids and travel into Lake Ontario. In 1954, the United States agreed to joint development of the international sections of the St. Lawrence River. The St. Lawrence Seaway was opened in 1959 and permits ocean-going ships to go all the way to the southwest corner of Lake Superior near Duluth, Minnesota. During WWII, German U-boats sank several merchant marine ships and three Canadian warships in the lower St. Lawrence River, the Strait of Belle Isle, Cabot Strait and the Gulf of Saint Lawrence. The bottom of the St. Lawrence River is littered with the wreckage of these ships and other ships which were lost during storms. The International Joint Commission recommended that the Canada and United States jointly improve navigation on the St. Lawrence River from Lake Ontario to Montreal. This lead to the signing of the St. Lawrence Treaty. Steel companies supported the treaties since the new St. Lawrence Seaway could get Labrador iron ore to the United States mills in the Great Lakes region. The Seaway’s power dams generate 3.5 million kilowatts of electricity which is provided to industry and to thousands of consumers in the New York State, New England and parts of Canada. The electric power generated by the project would be shared equally. This paper highlights how the geological and landscape properties of the St. Lawrence River watershed were responsible for the successful economic development of this important and historically-rich region of North America. Planned economic and urban development of the St. Lawrence River basin by USACE was blocked by the “Save the River” campaign. Environmental challenges include disposal of treated and untreated wastewater, water pollution, and shore erosion, invasive species and flooding.
基金supported financially by the NSFC projects(Grant Nos.U1403291,41802074,41830216,41572052)projects of the China Geological Survey(Grant Nos.1212011120477,1212010611803,1212010811033,12120113096500,12120113094000 and DD20160123)+1 种基金the IGCP 662 project’Orogenic Architecture and Crustal Growth from Accretion to Collision’the IUGS Big Science Program’Deep-time Digital Earth(DDE)’.
文摘The Appalachian orogen in North America is currently considered to be a Paleozoic accretion-type orogenic belt,or a collage,formed by collision of many ancient blocks between Laurentian and Gondwanan margins(Williams,1979;Williams et al.,1988;van Staal et al.,2007).Recently,major progress has been made in understanding the characteristics and tectonic evolution of the outboard peri-Laurentian and peri-Gondwanan terranes of the Iapetus Ocean(van Staal et al.,2009,2012).
文摘纽芬兰-拉布拉多省地处加拿大地盾东缘,成矿条件十分优越,是加拿大重要的镍矿成矿区,矿化类型多样。文章基于前人对该区镍矿床和矿化的研究,从区域成矿地质背景、矿化类型及地质特征、地球物理特征、勘探潜力、勘查态势等等方面进行了系统分析。拉布拉多地区的镍矿资源主要分布于辉长质—橄长质镁铁质岩石分布区,主要与中元古代侵入的辉长岩、斜长岩、橄长岩、辉石岩有关,或与太古宙超镁铁质变火山岩有关,矿化类型有橄长岩和辉长岩型、辉石岩型、斜长岩型、铁闪长岩型、火山岩(科马提岩)型;Voisey′s Bay Ni-Cu-Co硫化物矿床是拉布拉多地区已发现的大型镍矿床。纽芬兰地区的镍矿资源主要与古生代辉长-闪长质侵入岩、前寒武系镁铁质片麻岩有关,矿化类型主要有辉长岩型、镁铁质片麻岩型、火山热液型。纽芬兰-拉布拉多省的镍矿勘查前景乐观。
文摘加拿大阿巴拉契亚造山带纽芬兰岛Humber带基底地块属性及地壳生长演化是近年来关注的科学问题,尤其是岛内西南部的Indian Head Range地块,其年龄组成与同位素特征研究对区域基底构造属性划分与对比至关重要。本文对Indian Head Range地块内的二长花岗岩岩体进行了锆石U⁃Pb定年,得到其^(206)Pb/^(238)U加权平均年龄值为1149±4 Ma,代表该岩体的侵位年龄。这一定年结果表明该岩体具有中元古代晚期的年龄,为该地块格林威尔期岩浆事件的存在提供了新的年龄证据。Nd⁃Hf同位素分析结果显示,该二长花岗岩岩体εNd值为-2.3,εHf值介于+1.93~+3.65之间,两阶段Hf模式年龄介于1.84~1.73 Ga之间。结合前人研究,我们认为Humber带内各地块发育约1.5 Ga、1.15 Ga和1.0 Ga的3期花岗质岩浆事件,它们具有相似的Hf模式年龄值,暗示它们均来源于古元古代新生地壳物质的再造。带内格林威尔基底地块均为原地基底,且与劳伦大陆远端东部边缘具有一致的岩浆-构造演化史。以上研究对Humber带内格林威尔基底地块的亲缘性及地壳生长提供新的制约,并为阿巴拉契亚造山带内古老微陆块的溯源对比提供依据。
