Recent geochronological investigations reinforce the early suggestion that the upper part of the Paleoproterozoic Huronian Supergroup of Ontario,Canada is present in the Animikie Basin on the south shore of Lake Super...Recent geochronological investigations reinforce the early suggestion that the upper part of the Paleoproterozoic Huronian Supergroup of Ontario,Canada is present in the Animikie Basin on the south shore of Lake Superior.These rocks,beginning with the glaciogenic Gowganda Formation,are interpreted as passive margin deposits.The absence of the lower Huronian(rift succession) from the Animikie Basin may be explained by attributing the oldest Paleoroterozoic rocks in the Animikie Basin(Chocolay Group)to deposition on the upper plate of a north-dipping detachment fault,which lacks sediments of the rift phase.Following thermal uplift that led to opening of the Huronian Ocean on the south side of what is now the Superior province,renewed uplift(plume activity) caused large-scale gravitational folding of the Huronian Supergroup accompanied by intrusion of the Nipissing diabase suite and Senneterre dikes at about 2.2 Ga.Termination of passive margin sedimentation is normally followed by ocean closure but in the Huronian and Animikie basins there was a long hiatus- the Great Stratigraphic Gap- which lasted for about 350 Ma.This hiatus is attributed to a second prolonged thermal uplift of part of Kenorland that culminated in complete dismemberment of the supercontinent shortly before 2.0 Ga by opening of the Circum-Superior Ocean.These events caused regional uplift(the Great Stratigraphic Gap) and delayed completion of the Huronian Wilson Cycle until a regional compressional tectonic episode,including the Penokean orogeny,belatedly flooded the southern margin of the Superior province with foreland basin deposits,established the limits of the Superior structural province and played an important role in constructing Laurentia.展开更多
位于美国和加拿大之间。从苏必利尔湖德卢斯港向东到大西洋出口，全长大约15300公里的圣劳伦斯航道（Saint Lawrence Seaway）是北美洲的格雷特湖（the Great Lakes）。也是美洲五大湖水系和圣劳伦斯水系通航河道的总称。从西部海拔183...位于美国和加拿大之间。从苏必利尔湖德卢斯港向东到大西洋出口，全长大约15300公里的圣劳伦斯航道（Saint Lawrence Seaway）是北美洲的格雷特湖（the Great Lakes）。也是美洲五大湖水系和圣劳伦斯水系通航河道的总称。从西部海拔183米的苏必利尔湖（the Superior Lake）、密歇根湖（the Michigan Lake）、休伦湖（the Huron Lake）、伊利湖（the Eire Lake）和到最东部的海拔74米的安大略湖（the Ontario Lake），五大湖泊由高到低，为大约25000年以前冰川运动形成的世界上面积最大的淡水湖泊群。展开更多
基金financial assistance in past years from the Natural Science and Engineering Research Council of Canada(NSERC)
文摘Recent geochronological investigations reinforce the early suggestion that the upper part of the Paleoproterozoic Huronian Supergroup of Ontario,Canada is present in the Animikie Basin on the south shore of Lake Superior.These rocks,beginning with the glaciogenic Gowganda Formation,are interpreted as passive margin deposits.The absence of the lower Huronian(rift succession) from the Animikie Basin may be explained by attributing the oldest Paleoroterozoic rocks in the Animikie Basin(Chocolay Group)to deposition on the upper plate of a north-dipping detachment fault,which lacks sediments of the rift phase.Following thermal uplift that led to opening of the Huronian Ocean on the south side of what is now the Superior province,renewed uplift(plume activity) caused large-scale gravitational folding of the Huronian Supergroup accompanied by intrusion of the Nipissing diabase suite and Senneterre dikes at about 2.2 Ga.Termination of passive margin sedimentation is normally followed by ocean closure but in the Huronian and Animikie basins there was a long hiatus- the Great Stratigraphic Gap- which lasted for about 350 Ma.This hiatus is attributed to a second prolonged thermal uplift of part of Kenorland that culminated in complete dismemberment of the supercontinent shortly before 2.0 Ga by opening of the Circum-Superior Ocean.These events caused regional uplift(the Great Stratigraphic Gap) and delayed completion of the Huronian Wilson Cycle until a regional compressional tectonic episode,including the Penokean orogeny,belatedly flooded the southern margin of the Superior province with foreland basin deposits,established the limits of the Superior structural province and played an important role in constructing Laurentia.
文摘位于美国和加拿大之间。从苏必利尔湖德卢斯港向东到大西洋出口，全长大约15300公里的圣劳伦斯航道（Saint Lawrence Seaway）是北美洲的格雷特湖（the Great Lakes）。也是美洲五大湖水系和圣劳伦斯水系通航河道的总称。从西部海拔183米的苏必利尔湖（the Superior Lake）、密歇根湖（the Michigan Lake）、休伦湖（the Huron Lake）、伊利湖（the Eire Lake）和到最东部的海拔74米的安大略湖（the Ontario Lake），五大湖泊由高到低，为大约25000年以前冰川运动形成的世界上面积最大的淡水湖泊群。
