Dyke swarms frequently act as natural barriers,obstructing or deflecting stream courses.Streams tend to flow along the outcrop ridges of dykes,resulting in acute junction angles.Dykes serve as structural controls by i...Dyke swarms frequently act as natural barriers,obstructing or deflecting stream courses.Streams tend to flow along the outcrop ridges of dykes,resulting in acute junction angles.Dykes serve as structural controls by influencing the orientation of streams.The relationship between stream junction angles and dyke orientation is a significant factor in stream confluences.Terrain plays a crucial role in directing the river’s flow path and shaping its characteristics.This research paper investigates the impact of dyke orientation on stream junction angles through stream hierarchy analysis.The Rangavali River,a left-bank tributary of the Tapi River,flows for a distance of 45.65 km,crossing 21 East-West(E-W)trending dykes within a 215.95 km2 basin,which forms part of the Deccan Traps.To examine the relationship between dyke orientation and stream junction angles,inputs from Google Earth imagery,LISS III im ages,SOI topographical maps,quadrangle maps,and Cartosat DEM were used to delineate the Rangavali basin and extract dyke features.The Rangavali River basin is a sixth-order drainage system that exhibits a superimposed drainage pattern within the Tapi dyke swarm zone.The prominent linear dyke ridges are predominantly aligned in an East-West direction(average angle N81˚),with a dyke density of 0.51 km/km2.The average junction angle of streams within 100 m upstream and downstream of the dyke ridges is 81˚,compared to an av-erage of 78˚in non-dyke areas.The trend of acute junction angles is attributed to the orientation of the dykes and the distance of streams from the parallel-aligned dyke ridges.This study demonstrates that dyke ridges not only redirect stream flow but also control drainage density and network development.The findings have broader implications for watershed management,flood risk as sessment,infrastructure planning,and groundwater exploration in basaltic terrains and contribute significantly to the understanding of fluvial-structural in teractions in volcanic landscapes.展开更多
This study proposes three models to explain the mechanism of the three major types of mafic dyke swarms. Parallel dyke swarms form in response to a regional stress field, e.g. the mafic dyke swarms in the North China ...This study proposes three models to explain the mechanism of the three major types of mafic dyke swarms. Parallel dyke swarms form in response to a regional stress field, e.g. the mafic dyke swarms in the North China Craton, whereas small radiating dyke swarm forms due to stress constructions around a plutonic or volcanic edifice, such as the dyke swarm at Spanish Peak, USA. The third type of radiating dyke swarm is giant fan-shaped dyke swarm such as the Mackenzie dyke swarm. Fractures that formed prior to magmatism may play a vital role in dictating the dyke swarm geometry. In most of the cases, the pre-existing fractures are induced by tectonic stresses and not by magma injection though magma injection can increase the fracture size by propagation at the dyke tip.展开更多
The mafic dykes are composed of a series of northwest-trending diabase in Kuokesu of the Kuruktag region, Xinjiang. Four whole-rock samples of the mafic dykes in the region give an 40Ar/36Ar–40K/36Ar isochron age of ...The mafic dykes are composed of a series of northwest-trending diabase in Kuokesu of the Kuruktag region, Xinjiang. Four whole-rock samples of the mafic dykes in the region give an 40Ar/36Ar–40K/36Ar isochron age of 282 Ma with the initial 40Ar/36Ar = 507. The characteristics of the major, trace and rare earth elements of the dyke rocks indicate that they belong to the calc-alkaline series and were emplaced in extensional structures at an intermediate depth of the crust. This shows that there was a large-scale extension in the Permian Period, which might be associated with the post-collisional extension of the ancient Tianshan Mountains.展开更多
About 300 mafic dykes are intruded Eocene volcanic and pyroclastic rocks,north east of Meshkinshahr city in the NW of Iran.Most of dyke swarms display NNE-SSE trend.Their composition varies from basalt to tephrite and
Venusian coronae are large(60-2600 km diameter)tectono-magmatic features characterized by quasi-circular graben-fissure systems and topographic features such as a central dome,central depression,circular rim or circular
Dyke swarms can be divided into three types:parallel dyke swarms,radiating dyke swarms and fan-shape dyke swarm,for which the mechanisms of formation are different(Fig.1).Parallel dyke swarms form in response
The Sr, Nd and Pb isotopic characteristics of the Wudang basic dyke swarms and basic volcanics of the Yaolinghe Group show that they were derived from the same multi\|component mixing source in the mantle. The Wudang ...The Sr, Nd and Pb isotopic characteristics of the Wudang basic dyke swarms and basic volcanics of the Yaolinghe Group show that they were derived from the same multi\|component mixing source in the mantle. The Wudang basic dyke swarms have (\{\}\+\{87\}Sr/\{\}\+\{86\}Sr)\-i=\{0.6905\}～\{0.7061\}, ε\-\{Nd\}(t)=\{-1.9\}～\{5.0\}, Δ\{\}\+\{208\}Pb/\+\{204\}Pb=\{35.49\}～\{190.26\}, Δ\{\}\+\{207\}Pb/\{\}\+\{204\}Pb=4～85, low Th/Ta and a wide range of La/Yb ratios; and the basic volcanics of the Yaolinghe Group have (\{\}\+\{87\}Sr/\{\}\+\{86\}Sr)\-i=\{0.6487\}～\{0.7075\}, ε\-\{Nd\}(t)=\{0.11\}～\{3.94\}, Δ\{\}\+\{208\}Pb/\{\}\+\{204\}Pb=\{-81.58\}～\{219.95\}, Δ\{\}\+\{207\}Pb/\{\}\+\{204\}Pb=\{4.44\}～\{16.68\} and higher Th/Ta and La/Yb ratios, indicating that their source is a mixture of DM and EMII, and the basic volcanics of the Yaolinghe Group were contaminated by crust materials en rout to the surface. Based on the geochemical features of continental tholeiitic basalts and being products of different facies derived from the same source, it can be concluded that an important rifting event in the South Qinling basement block occurred during Neoproterozoic, followed by a setting of oceanic basin in the Early Paleozoic.展开更多
A 1:2500 000 map of major Precambrian mafic dyke swarms and related units in the North China Craton will be presented,and the features and geological implications of;0 swarms will be discussed and summarized:
During the past decade,generations of Precambrian mafic dykes/sills have been investigated and revealed in the North China Craton(NCC).Researchers identified more than 20 episodes of Precambrian dyke swarms,
Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construc...Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the展开更多
An extensive survey of dykes in the Valles Marineris troughs(chasmata)on Mars has been undertaken.Most dykes are observed along the chasma walls(Mège and Gurgurewicz,2016),in the spur-and-gully morphology that
Morocco hosts a Dyke Swarm Bonanza!Remarkable mafic dyke and sill swarms(plumbing system of Large Igneous Provinces,LIPs)have been recognized in the Sahara and in most inliers in the Anti-Atlas of southern
A precise dating of a mafic dyke of a swarm in shield areas has great advantage to identify Large Igneous Provinces(LIPs;short-lived,mantle-generated magmatic event)(Bryan and Ernst,2008;Ernst et al.,2010).Such
The Precambrian rocks in Wadi Fatirah-Wadi Abu Zawal area, Eastern Desert of Egypt, are crosscut by numerous post-orogenic dyke swarms. Image processing techniques are applied to the enhanced Thematic Mapper plus (ETM...The Precambrian rocks in Wadi Fatirah-Wadi Abu Zawal area, Eastern Desert of Egypt, are crosscut by numerous post-orogenic dyke swarms. Image processing techniques are applied to the enhanced Thematic Mapper plus (ETM+) data for lithological mapping and spectral characterization of these dyke swarms. Band ratios and principal component analysis (PCA) yield conspicuously effective results. Depending on mineralogical and geochemical data, two petrogenetic groups of dyke swarms have been recognized: the first group (mafic dykes) comprises basalt, basaltic andesite and andesite, while the second group (felsic dykes) corresponds to dacite and rhyolite in composition. The mafic dykes are tholeiitic to calc-alkaline, while the felsic dykes display significant calc-alkaline affinity. The Na2O, K2O, Ba, Y, Rb, Zr and Th contents increase from basic to acidic dykes and vice versa relative to CaO, MgO, Fe2O3, Sr, V, Co and Ni contents. These dyke swarms have been emplaced in post-collisional, destructive plate margin settings during periods of extension. The basic dykes have characteristics of volcanic arc setting, whereas the acidic dykes display geochemical features of within plate rocks. The chemical differences between the mafic and felsic dyke swarms favor that the two groups of dyke swarms cannot be related to the same magma source, but they are formed from two different parental magmas.展开更多
Focusing on geological,geochemical and geophysical aspects of dykes and related units,the International Dyke Conference(IDC)series was launched in Toronto,Canada in 1985 by Prof.Henry C.Halls(University of Toronto).It...Focusing on geological,geochemical and geophysical aspects of dykes and related units,the International Dyke Conference(IDC)series was launched in Toronto,Canada in 1985 by Prof.Henry C.Halls(University of Toronto).It has continued approximately every five years with展开更多
The Singhbhum craton of the eastern Indian shield consists of two major crustal provinces viz.,Chotanagpur Gneissic Complex(CGC)and Singhbhum Granite Complex;separated by a Singhbhum Mobile Belt.There
In Espírito Santo State,Brazil,between the municipalities of Vitória,Colatina and Ecoporanga,there is a mountainous region characterized by a shear zone which trends NNW-SSE and is filled by a diabase
Giant mafic dyke swarms are a key component of the feeder system of Large Igneous Provinces（LIPs）,large volume（>0.1 Mkm;;frequently above>1 M km;）,mainly mafic（-ultramafic）magmatic events of intraplate aff...Giant mafic dyke swarms are a key component of the feeder system of Large Igneous Provinces（LIPs）,large volume（>0.1 Mkm;;frequently above>1 M km;）,mainly mafic（-ultramafic）magmatic events of intraplate affinity.展开更多
The high-pressure metamorphosed Gridino dyke swarm comprises a major group of Mesoarchean 2.87-2.82 Ga mafic dykes intruded within the Mesoarchean continental crust of the Kola craton(the Belomorian tectonic province
There are only two quantitative tools for Precambrian paleogeographic reconstructions–paleomagnetic data and dyke swarms geometries.Paleomagnetic data provide information about paleolatitudes and orientation of rigid
文摘Dyke swarms frequently act as natural barriers,obstructing or deflecting stream courses.Streams tend to flow along the outcrop ridges of dykes,resulting in acute junction angles.Dykes serve as structural controls by influencing the orientation of streams.The relationship between stream junction angles and dyke orientation is a significant factor in stream confluences.Terrain plays a crucial role in directing the river’s flow path and shaping its characteristics.This research paper investigates the impact of dyke orientation on stream junction angles through stream hierarchy analysis.The Rangavali River,a left-bank tributary of the Tapi River,flows for a distance of 45.65 km,crossing 21 East-West(E-W)trending dykes within a 215.95 km2 basin,which forms part of the Deccan Traps.To examine the relationship between dyke orientation and stream junction angles,inputs from Google Earth imagery,LISS III im ages,SOI topographical maps,quadrangle maps,and Cartosat DEM were used to delineate the Rangavali basin and extract dyke features.The Rangavali River basin is a sixth-order drainage system that exhibits a superimposed drainage pattern within the Tapi dyke swarm zone.The prominent linear dyke ridges are predominantly aligned in an East-West direction(average angle N81˚),with a dyke density of 0.51 km/km2.The average junction angle of streams within 100 m upstream and downstream of the dyke ridges is 81˚,compared to an av-erage of 78˚in non-dyke areas.The trend of acute junction angles is attributed to the orientation of the dykes and the distance of streams from the parallel-aligned dyke ridges.This study demonstrates that dyke ridges not only redirect stream flow but also control drainage density and network development.The findings have broader implications for watershed management,flood risk as sessment,infrastructure planning,and groundwater exploration in basaltic terrains and contribute significantly to the understanding of fluvial-structural in teractions in volcanic landscapes.
基金supported by funds from the National Natural Science Foundation of China Grant(Nos.40772121,40314141 and 40172066)China National Projects 973(No.2009CB219302)
文摘This study proposes three models to explain the mechanism of the three major types of mafic dyke swarms. Parallel dyke swarms form in response to a regional stress field, e.g. the mafic dyke swarms in the North China Craton, whereas small radiating dyke swarm forms due to stress constructions around a plutonic or volcanic edifice, such as the dyke swarm at Spanish Peak, USA. The third type of radiating dyke swarm is giant fan-shaped dyke swarm such as the Mackenzie dyke swarm. Fractures that formed prior to magmatism may play a vital role in dictating the dyke swarm geometry. In most of the cases, the pre-existing fractures are induced by tectonic stresses and not by magma injection though magma injection can increase the fracture size by propagation at the dyke tip.
基金This study was supported by the State"Ninth Five-Year Plan"Key Project No.96-915-05-02.
文摘The mafic dykes are composed of a series of northwest-trending diabase in Kuokesu of the Kuruktag region, Xinjiang. Four whole-rock samples of the mafic dykes in the region give an 40Ar/36Ar–40K/36Ar isochron age of 282 Ma with the initial 40Ar/36Ar = 507. The characteristics of the major, trace and rare earth elements of the dyke rocks indicate that they belong to the calc-alkaline series and were emplaced in extensional structures at an intermediate depth of the crust. This shows that there was a large-scale extension in the Permian Period, which might be associated with the post-collisional extension of the ancient Tianshan Mountains.
文摘About 300 mafic dykes are intruded Eocene volcanic and pyroclastic rocks,north east of Meshkinshahr city in the NW of Iran.Most of dyke swarms display NNE-SSE trend.Their composition varies from basalt to tephrite and
文摘Venusian coronae are large(60-2600 km diameter)tectono-magmatic features characterized by quasi-circular graben-fissure systems and topographic features such as a central dome,central depression,circular rim or circular
文摘Dyke swarms can be divided into three types:parallel dyke swarms,radiating dyke swarms and fan-shape dyke swarm,for which the mechanisms of formation are different(Fig.1).Parallel dyke swarms form in response
文摘The Sr, Nd and Pb isotopic characteristics of the Wudang basic dyke swarms and basic volcanics of the Yaolinghe Group show that they were derived from the same multi\|component mixing source in the mantle. The Wudang basic dyke swarms have (\{\}\+\{87\}Sr/\{\}\+\{86\}Sr)\-i=\{0.6905\}～\{0.7061\}, ε\-\{Nd\}(t)=\{-1.9\}～\{5.0\}, Δ\{\}\+\{208\}Pb/\+\{204\}Pb=\{35.49\}～\{190.26\}, Δ\{\}\+\{207\}Pb/\{\}\+\{204\}Pb=4～85, low Th/Ta and a wide range of La/Yb ratios; and the basic volcanics of the Yaolinghe Group have (\{\}\+\{87\}Sr/\{\}\+\{86\}Sr)\-i=\{0.6487\}～\{0.7075\}, ε\-\{Nd\}(t)=\{0.11\}～\{3.94\}, Δ\{\}\+\{208\}Pb/\{\}\+\{204\}Pb=\{-81.58\}～\{219.95\}, Δ\{\}\+\{207\}Pb/\{\}\+\{204\}Pb=\{4.44\}～\{16.68\} and higher Th/Ta and La/Yb ratios, indicating that their source is a mixture of DM and EMII, and the basic volcanics of the Yaolinghe Group were contaminated by crust materials en rout to the surface. Based on the geochemical features of continental tholeiitic basalts and being products of different facies derived from the same source, it can be concluded that an important rifting event in the South Qinling basement block occurred during Neoproterozoic, followed by a setting of oceanic basin in the Early Paleozoic.
文摘A 1:2500 000 map of major Precambrian mafic dyke swarms and related units in the North China Craton will be presented,and the features and geological implications of;0 swarms will be discussed and summarized:
基金supported by the Major State Basic Research Development Program of China (973 Program No: 2012CB416601)+1 种基金the National Natural Science Foundation of China (No: 41322018) projectsthe National High-Level Talents Special Support Plan
文摘During the past decade,generations of Precambrian mafic dykes/sills have been investigated and revealed in the North China Craton(NCC).Researchers identified more than 20 episodes of Precambrian dyke swarms,
基金co-supported by National Natural Science Foundation of China (Project number 41502201)"Western Light" project of Chinese Academy of Sciences (XBBS201301)
文摘Dykes are a special kind of intrusive rocks which were formed by deep magma intruded into the existing brittle fractures in the crust.Dykes swarms in different tectonic environments are very significant to re-construct the
文摘An extensive survey of dykes in the Valles Marineris troughs(chasmata)on Mars has been undertaken.Most dykes are observed along the chasma walls(Mège and Gurgurewicz,2016),in the spur-and-gully morphology that
基金supported by project of The Academy Hassan II for Science and Technology (Morocco) to NY
文摘Morocco hosts a Dyke Swarm Bonanza!Remarkable mafic dyke and sill swarms(plumbing system of Large Igneous Provinces,LIPs)have been recognized in the Sahara and in most inliers in the Anti-Atlas of southern
文摘A precise dating of a mafic dyke of a swarm in shield areas has great advantage to identify Large Igneous Provinces(LIPs;short-lived,mantle-generated magmatic event)(Bryan and Ernst,2008;Ernst et al.,2010).Such
文摘The Precambrian rocks in Wadi Fatirah-Wadi Abu Zawal area, Eastern Desert of Egypt, are crosscut by numerous post-orogenic dyke swarms. Image processing techniques are applied to the enhanced Thematic Mapper plus (ETM+) data for lithological mapping and spectral characterization of these dyke swarms. Band ratios and principal component analysis (PCA) yield conspicuously effective results. Depending on mineralogical and geochemical data, two petrogenetic groups of dyke swarms have been recognized: the first group (mafic dykes) comprises basalt, basaltic andesite and andesite, while the second group (felsic dykes) corresponds to dacite and rhyolite in composition. The mafic dykes are tholeiitic to calc-alkaline, while the felsic dykes display significant calc-alkaline affinity. The Na2O, K2O, Ba, Y, Rb, Zr and Th contents increase from basic to acidic dykes and vice versa relative to CaO, MgO, Fe2O3, Sr, V, Co and Ni contents. These dyke swarms have been emplaced in post-collisional, destructive plate margin settings during periods of extension. The basic dykes have characteristics of volcanic arc setting, whereas the acidic dykes display geochemical features of within plate rocks. The chemical differences between the mafic and felsic dyke swarms favor that the two groups of dyke swarms cannot be related to the same magma source, but they are formed from two different parental magmas.
文摘Focusing on geological,geochemical and geophysical aspects of dykes and related units,the International Dyke Conference(IDC)series was launched in Toronto,Canada in 1985 by Prof.Henry C.Halls(University of Toronto).It has continued approximately every five years with
文摘The Singhbhum craton of the eastern Indian shield consists of two major crustal provinces viz.,Chotanagpur Gneissic Complex(CGC)and Singhbhum Granite Complex;separated by a Singhbhum Mobile Belt.There
基金Repsol Sinopec Petroleum Brazil for its financial support to this interinstitutional research
文摘In Espírito Santo State,Brazil,between the municipalities of Vitória,Colatina and Ecoporanga,there is a mountainous region characterized by a shear zone which trends NNW-SSE and is filled by a diabase
文摘Giant mafic dyke swarms are a key component of the feeder system of Large Igneous Provinces（LIPs）,large volume（>0.1 Mkm;;frequently above>1 M km;）,mainly mafic（-ultramafic）magmatic events of intraplate affinity.
文摘The high-pressure metamorphosed Gridino dyke swarm comprises a major group of Mesoarchean 2.87-2.82 Ga mafic dykes intruded within the Mesoarchean continental crust of the Kola craton(the Belomorian tectonic province
文摘There are only two quantitative tools for Precambrian paleogeographic reconstructions–paleomagnetic data and dyke swarms geometries.Paleomagnetic data provide information about paleolatitudes and orientation of rigid
