国际地层委员会将中元古界底界界线年龄定为1600 Ma,1600～1400 Ma为Calymmian（盖层系）,表示全球地台盖层形成时期.华北地台基底固结时间为1800Ma,固结后即进入伸展裂解作用时期,首先是山西吕梁山区、晋南中条山、豫西熊耳山区裂解发...国际地层委员会将中元古界底界界线年龄定为1600 Ma,1600～1400 Ma为Calymmian（盖层系）,表示全球地台盖层形成时期.华北地台基底固结时间为1800Ma,固结后即进入伸展裂解作用时期,首先是山西吕梁山区、晋南中条山、豫西熊耳山区裂解发展成三叉裂陷槽（Aulacogen）.吕梁山区小两岭组火山岩形成年龄有1778±20 Ma（SHRIMP U Pb锆石）及1779±20 Ma（LA ICP MS U Pb锆石）两个数值;豫西熊耳群顶部马家河组和中部鸡蛋坪组及下部许山组火山岩年龄分别为1776±20 Ma、1791±20 Ma和1783±13 Ma（SHRIMP U Pb锆石）,1776～1800Ma为火山岩的形成年龄;将1800Ma作为小两岭组与熊耳群两个火山岩组的底界年龄应当是合理的.吕梁山区的汉高山群为碎屑岩夹火山岩,代表吕梁陕豫三叉裂陷槽北支中的快速充填,与小两岭组为同时期沉积.汉高山群、大古石组（熊耳群底部沉积岩）为1800Ma裂解开始的盖层沉积,小两岭组火山岩、相关的辉绿岩墙及熊耳群火山岩均为裂解时期的岩浆作用产物.北京密云环斑花岗岩侵位时间为1700Ma,代表燕山太行山裂陷槽裂解的起始时间也即燕山地区长城系常州沟组底界年龄.北京密云地区环斑花岗岩风化壳上覆常州沟组年龄可确定为1650Ma,它不应被看作常州沟组最低层位的年龄,而是裂陷槽裂解后密云地区开始接受沉积的年龄,1700Ma、1650Ma代表常州沟组在不同地区的底界年龄,但均不等于长城系或中元古界的底界年龄.1600Ma为高于庄组底界年龄,即长城系与蓟县系的界线年龄,也是国际地层委员会中元古界的底界年龄.1600 Ma代表燕山太行山裂陷槽闭合的年龄,也是华北地台始自1800Ma伸展裂解作用的最终结束时期.1600Ma是新的陆表海盆地发展的起始时间,是重要的华北地台构造转换的时期.因此,1800与1600 Ma代表华北地台重大地质构造事件的年龄,具大区域构造意义,依据对前寒�展开更多
Several blueschist outcrops, specially glaucophane-bearing ones, were found in Dexing, eastern Jiangnan belt. The latest researches suggest that the blueschists distributed in the Late Proterozoic ophiolite melange bl...Several blueschist outcrops, specially glaucophane-bearing ones, were found in Dexing, eastern Jiangnan belt. The latest researches suggest that the blueschists distributed in the Late Proterozoic ophiolite melange blocks of the northeastern Jiangxi fault zone between the Jiuling tectonic region and the Huaiyu tectonic region of volcanic are that is located near the frontier of Jiangxi, Zhejiang and Anhui provinces (Fig. 1).展开更多
Least-squares solution of AXB = D with respect to symmetric positive semidefinite matrix X is considered. By making use of the generalized singular value decomposition, we derive general analytic formulas, and present...Least-squares solution of AXB = D with respect to symmetric positive semidefinite matrix X is considered. By making use of the generalized singular value decomposition, we derive general analytic formulas, and present necessary and sufficient conditions for guaranteeing the existence of the solution. By applying MATLAB 5.2, we give some numerical examples to show the feasibility and accuracy of this construction technique in the finite precision arithmetic.展开更多
文摘国际地层委员会将中元古界底界界线年龄定为1600 Ma,1600～1400 Ma为Calymmian（盖层系）,表示全球地台盖层形成时期.华北地台基底固结时间为1800Ma,固结后即进入伸展裂解作用时期,首先是山西吕梁山区、晋南中条山、豫西熊耳山区裂解发展成三叉裂陷槽（Aulacogen）.吕梁山区小两岭组火山岩形成年龄有1778±20 Ma（SHRIMP U Pb锆石）及1779±20 Ma（LA ICP MS U Pb锆石）两个数值;豫西熊耳群顶部马家河组和中部鸡蛋坪组及下部许山组火山岩年龄分别为1776±20 Ma、1791±20 Ma和1783±13 Ma（SHRIMP U Pb锆石）,1776～1800Ma为火山岩的形成年龄;将1800Ma作为小两岭组与熊耳群两个火山岩组的底界年龄应当是合理的.吕梁山区的汉高山群为碎屑岩夹火山岩,代表吕梁陕豫三叉裂陷槽北支中的快速充填,与小两岭组为同时期沉积.汉高山群、大古石组（熊耳群底部沉积岩）为1800Ma裂解开始的盖层沉积,小两岭组火山岩、相关的辉绿岩墙及熊耳群火山岩均为裂解时期的岩浆作用产物.北京密云环斑花岗岩侵位时间为1700Ma,代表燕山太行山裂陷槽裂解的起始时间也即燕山地区长城系常州沟组底界年龄.北京密云地区环斑花岗岩风化壳上覆常州沟组年龄可确定为1650Ma,它不应被看作常州沟组最低层位的年龄,而是裂陷槽裂解后密云地区开始接受沉积的年龄,1700Ma、1650Ma代表常州沟组在不同地区的底界年龄,但均不等于长城系或中元古界的底界年龄.1600Ma为高于庄组底界年龄,即长城系与蓟县系的界线年龄,也是国际地层委员会中元古界的底界年龄.1600 Ma代表燕山太行山裂陷槽闭合的年龄,也是华北地台始自1800Ma伸展裂解作用的最终结束时期.1600Ma是新的陆表海盆地发展的起始时间,是重要的华北地台构造转换的时期.因此,1800与1600 Ma代表华北地台重大地质构造事件的年龄,具大区域构造意义,依据对前寒�
基金Project supported by the National Natural Science Foundation of Chinathe "Laboratoire de Géologie Structurale" of Orleans Université, France
文摘Several blueschist outcrops, specially glaucophane-bearing ones, were found in Dexing, eastern Jiangnan belt. The latest researches suggest that the blueschists distributed in the Late Proterozoic ophiolite melange blocks of the northeastern Jiangxi fault zone between the Jiuling tectonic region and the Huaiyu tectonic region of volcanic are that is located near the frontier of Jiangxi, Zhejiang and Anhui provinces (Fig. 1).
基金Subsidized by The Special Funds For Major State Basic Research Project G1999032803.
文摘Least-squares solution of AXB = D with respect to symmetric positive semidefinite matrix X is considered. By making use of the generalized singular value decomposition, we derive general analytic formulas, and present necessary and sufficient conditions for guaranteeing the existence of the solution. By applying MATLAB 5.2, we give some numerical examples to show the feasibility and accuracy of this construction technique in the finite precision arithmetic.
