文章以3个岩石地球化学数据库--海底岩石学数据库(Petrological Database of the Ocean Floor,PetDB)、海洋和大陆岩石地球化学(Geochemistry of Rocks of the Oceans and Continents,GEOROC)数据库及北美火山岩和侵入岩数据库(North Am...文章以3个岩石地球化学数据库--海底岩石学数据库(Petrological Database of the Ocean Floor,PetDB)、海洋和大陆岩石地球化学(Geochemistry of Rocks of the Oceans and Continents,GEOROC)数据库及北美火山岩和侵入岩数据库(North American Volcanic and Intrusive Rock Database,NAVDAT)作为基础数据集,依据岩石类型、关键组分完整性、地理信息完整性的标准,筛选出按火成岩主要组分、主要岩石类型划分的全球地球化学数据集,将这些数据集进行地理位置投图,并结合邻域分析等地理信息系统(Geographic Information System,GIS)技术进行纬度剖面数据分析与结果可视化。在15°N、15°S、45°N及45°S共4个剖面上的邻域分析投图结果中,以SiO 2为代表的多种氧化物在各个经度范围的质量分数异常位置和现存板块交界处、火山活动活跃区域的位置表现出契合现象,这符合在各大地质时代中发生的气候变化以及岩石圈构造运动的特点。安山岩与玄武岩的数据分布结果表明,2种岩石富集位置相似度较高,存在伴生关系。就全球尺度下的个别类型火成岩及其主量组分的空间分布规律研究而言,大数据思想的应用具有不可忽视的实用价值。展开更多
Based on the data of field measurement and drilling in the Tongling area, a series of numerical simulations are carried out by using the 'Surplus Space Method' (SSM), which is first put forward in this paper a...Based on the data of field measurement and drilling in the Tongling area, a series of numerical simulations are carried out by using the 'Surplus Space Method' (SSM), which is first put forward in this paper and applied to predict the shallow-seated magmatic bodies. The results of the numerical simulations show the existence and the 3-D shape of a conical magmatic structure at a depth of-1000 m beneath the center of the area: its top offsets southwards and bifurcates to several branches, while its lower part stretches northeastwards and contracts rapidly to a point at about -1000 m depth. This point is reckoned to be a 'sink' of magma system, transferring ore materials and heat energy from the deep magma chamber to the sub-surface apophyses. The preliminary application of the SSM proves that it may be developed as a new detection means for determining the existence of shallow-seated magmatic bodies and analyzing their three-dimensional features.展开更多
Plio-Quaternary magmatism in Italy exhibits an extremely variable composition, which spans almost entirely the spectrum of magmatic rocks occurring worldwide. Petrological and geochemical data pro-vide a basis for ...Plio-Quaternary magmatism in Italy exhibits an extremely variable composition, which spans almost entirely the spectrum of magmatic rocks occurring worldwide. Petrological and geochemical data pro-vide a basis for distinguishing various magmatic provinces, which show different maior element and/or trace element and/or isotopic compositions. The Tus-cany province (14-0.2 Ma) consists of silicic magmas generated through crustal anatexis, and of mantle-derived calcalkaline to ultrapotassic mafic rocks. The Roman, Umbria, Ernici-Roccamonfina and Neapolitan provinces (0.8 Ma to present) are formed by mantle-derived potassic to ultrapotassic rocks having variable trace element and isotopic compositions. The Aeolian arc (?1 Ma to present) mainly consists of calcalkaline to shoshonitic rocks. The Sicily province contains young to active centers (notably Etna) with a tholeiitic to Na-alkaline affinity. Finally, volcanoes of variable composition occur in Sardinia and, as seamounts, on the Tyrrhenian Sea floor. Magmas in the Aeolian arcand along the Italian peninsula have a subduction-related geochemical character, whereas the Sicily and Sardinia provinces display intraplate signatures.Intraplate and orogenic volcanics coexist on theTvrrhenian Sea floor.The geochemical and isotopic complexities of Plio-Quaternary magmatism reveal that the upper mantle beneath Italy consists of various domains, spanning both orogenic and anorogenic compositions. Isotopic data suggest that compositional heterogeneity originated from mixing between various mantle reservoirs, and between these and subduction-related crustal material.This probably occurred during the Cenozoic-Quaternary geodynamic evolution of the western Mediterranean.展开更多
文摘文章以3个岩石地球化学数据库--海底岩石学数据库(Petrological Database of the Ocean Floor,PetDB)、海洋和大陆岩石地球化学(Geochemistry of Rocks of the Oceans and Continents,GEOROC)数据库及北美火山岩和侵入岩数据库(North American Volcanic and Intrusive Rock Database,NAVDAT)作为基础数据集,依据岩石类型、关键组分完整性、地理信息完整性的标准,筛选出按火成岩主要组分、主要岩石类型划分的全球地球化学数据集,将这些数据集进行地理位置投图,并结合邻域分析等地理信息系统(Geographic Information System,GIS)技术进行纬度剖面数据分析与结果可视化。在15°N、15°S、45°N及45°S共4个剖面上的邻域分析投图结果中,以SiO 2为代表的多种氧化物在各个经度范围的质量分数异常位置和现存板块交界处、火山活动活跃区域的位置表现出契合现象,这符合在各大地质时代中发生的气候变化以及岩石圈构造运动的特点。安山岩与玄武岩的数据分布结果表明,2种岩石富集位置相似度较高,存在伴生关系。就全球尺度下的个别类型火成岩及其主量组分的空间分布规律研究而言,大数据思想的应用具有不可忽视的实用价值。
基金This study was financially supported by the National Important Basic Research and Development Planning Program(No.1999043206)the National Natural Science Foundation of China(No.40234051)+1 种基金the Special Plan of Science and Technology of the Ministry of Land and Resources(20010103)the"Trans-century Training Program for Outstanding Talents”Fund sponsored by the.Ministry of Education.
文摘Based on the data of field measurement and drilling in the Tongling area, a series of numerical simulations are carried out by using the 'Surplus Space Method' (SSM), which is first put forward in this paper and applied to predict the shallow-seated magmatic bodies. The results of the numerical simulations show the existence and the 3-D shape of a conical magmatic structure at a depth of-1000 m beneath the center of the area: its top offsets southwards and bifurcates to several branches, while its lower part stretches northeastwards and contracts rapidly to a point at about -1000 m depth. This point is reckoned to be a 'sink' of magma system, transferring ore materials and heat energy from the deep magma chamber to the sub-surface apophyses. The preliminary application of the SSM proves that it may be developed as a new detection means for determining the existence of shallow-seated magmatic bodies and analyzing their three-dimensional features.
文摘Plio-Quaternary magmatism in Italy exhibits an extremely variable composition, which spans almost entirely the spectrum of magmatic rocks occurring worldwide. Petrological and geochemical data pro-vide a basis for distinguishing various magmatic provinces, which show different maior element and/or trace element and/or isotopic compositions. The Tus-cany province (14-0.2 Ma) consists of silicic magmas generated through crustal anatexis, and of mantle-derived calcalkaline to ultrapotassic mafic rocks. The Roman, Umbria, Ernici-Roccamonfina and Neapolitan provinces (0.8 Ma to present) are formed by mantle-derived potassic to ultrapotassic rocks having variable trace element and isotopic compositions. The Aeolian arc (?1 Ma to present) mainly consists of calcalkaline to shoshonitic rocks. The Sicily province contains young to active centers (notably Etna) with a tholeiitic to Na-alkaline affinity. Finally, volcanoes of variable composition occur in Sardinia and, as seamounts, on the Tyrrhenian Sea floor. Magmas in the Aeolian arcand along the Italian peninsula have a subduction-related geochemical character, whereas the Sicily and Sardinia provinces display intraplate signatures.Intraplate and orogenic volcanics coexist on theTvrrhenian Sea floor.The geochemical and isotopic complexities of Plio-Quaternary magmatism reveal that the upper mantle beneath Italy consists of various domains, spanning both orogenic and anorogenic compositions. Isotopic data suggest that compositional heterogeneity originated from mixing between various mantle reservoirs, and between these and subduction-related crustal material.This probably occurred during the Cenozoic-Quaternary geodynamic evolution of the western Mediterranean.
