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成矿演化可以分成5个时期(Ma):(1)小岩石圈板块,褶皱作用期并发育绿岩带(3800~3000);(2)陆壳主块的形成(3000~2700);(3)初始超大陆,开始板块构造作用的影响(2700~1800);(4)原生陆壳的多重作用(1800~600);(5)深部地幔分异,以构造岩浆分异作用为主(600~0)。 相似文献
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科拉超深钻已反驳了基于地表的地质和地球物理研究所建立起来的东巴尔干地质深部构造模式。无论原先什么样的推测,超深钻孔在6840m~12000m这段深度并没有碰到玄武岩或麻粒岩等基性岩石,而钻到的是太古宙科拉岩系中的花岗片麻岩。在这段上,变质火山成因的岩石与变质陆源岩互层产出,残余层状特征仍保留下来,这是与褶皱随深度增加而减弱的观点不符。以最大深度处,钻孔遇到一新的构造层,这被三维磁场测量和地球化学资料的结果所证实。 UD-3钻孔核部的构造岩石分析证实了元古宙内生作用对科拉岩系的强烈影响。在中元古宙(1.8~2.0Ga),Pechenga火山沉积杂岩和太古宙的花岗片麻岩均遭受从葡萄 相似文献
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Organochlorine pesticide and trace metal monitoring of Russian rivers flowing to the Arctic Ocean: 1990-1996 总被引:1,自引:0,他引:1
Alexeeva LB Strachan WM Shlychkova VV Nazarova AA Nikanorov AM Korotova LG Koreneva VI 《Marine pollution bulletin》2001,43(1-6):71-85
Information is presented on the concentrations of organochlorine pesticides (HCHs and DDT residues) and trace metals (Fe, Cu, Zn and Ni) in waters of 15 large Russian rivers flowing to the Arctic Ocean during 1990-1996. Estimates of the corresponding annual fluxes are made. Other contaminants (Hg, Pb, Cr, Mn, beta-HCH and dihydroheptachlor) were examined briefly. Concentration data are presented as averaged annual means for each of the seven years with the ranges, standard deviations and numbers of samples. Also given are data on locations, the methods of analysis and limited quality assurance data. Data on discharges to the Northern Seas for the more frequently monitored contaminants are given for rivers accounting for >70% of the total northerly flows. Scaled-up fluxes to account for unmonitored rivers as well are given for each sea; totals over the period were: Fe, 1452; Cu, 15; Zn, 59 (x 10(3) t yr(-1)); alpha-HCH, 25; gamma-HCH, 44 (t yr(-1)). Ni was monitored at too few rivers to estimate its total Russian flux. The fluxes for the HCHs considerably exceed previous estimates and indicate that the Arctic Ocean is not in balance as much as was previously believed. 相似文献
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