The Altay orogenic belt of Xinjiang in NW China represents one of the important sites of juvenile crustal growth during the Phanerozoic. However, some important issues, e.g., tectonic evolution and petrogenesis, still...The Altay orogenic belt of Xinjiang in NW China represents one of the important sites of juvenile crustal growth during the Phanerozoic. However, some important issues, e.g., tectonic evolution and petrogenesis, still remain controversial. The picrites in the south margin of the Altay orogenic belt were discovered in the lower part of marine volcanic-sedimentary sequences of the northwest-striking Middle Devonian Beitashan Formation (Fm.), which consists chiefly of intermediate-basic volcanic rocks intercalated minor carbonate, siltstone and siliceous rocks. The picrites are usually highly porphyritic, and contain abundant forsteritic olivine phenocrysts with minor clinopyroxene distributed in the groundmass, which consist of olivine, clinopyroxene and plagioclase with minor Fe-Ti oxides. The MgO contents of the picrites range from 14 wt% to 22 wt% with Mg# (atomic Mg/(Mg+Fe) ratio) of 0.75-0.80. They are characterized by slightly negative Ti anomalies, remarkably negative Nb and Ta anomalies and slightly positive P and Sm anomalies with the similar abundances of HFSE as MORB on the MORB-normalized trace element patterns, all of which characterize typical island arc magmas. In combing with the southwestward migration of the magmas of the Beitashan Fm., we propose that the magmas may result from the southwestward subduction of Junggar ocean plate. The Zr/Nb ratios (23-66) of both picrites and basalts resemble the MORB (10-66), suggesting that they were derived from the MORB-like sources. However, the basalts and picrites display some distinguishable element ratios and REE patterns, e.g., Ti/V (23-35) and Zr/Sm (18-23) ratios of basalts are higher than those of picrites (14-17 and 14-15 respectively), and the basalts display flat-type REE-chondrite patterns whereas the picrites are characterized by lower total REE concentrations ((26-34)×10^-6) and slight enrichment of light REE. These distinguished geochemical characteristics could be interpreted by different partial melting degrees and mantle sources, i.e., the basalts were generated by lower partial melting of amphibole-bearing spinel peridotite which was metasomatized by fluids released from subducted oceanic crust, and the picrites were resulted from the higher degree of partial melting of metasomatized garnet peridotite under high temperature. In contrast, the andesite with significant LREE and LILE enrichment may be resulted from the partial melting of eclogites.展开更多
Background Numerous studies from Europe and North America have provided a wealth of information regarding the epidemiological and clinical characteristics of inflammatory bowel disease (IBD) in Caucasians. Previous ...Background Numerous studies from Europe and North America have provided a wealth of information regarding the epidemiological and clinical characteristics of inflammatory bowel disease (IBD) in Caucasians. Previous studies in China's Mainland have been limited by small patient numbers or by lack of detailed information about clinical subgroups of the disease. This study was carried out to assess the demographic and clinical characteristics of IBD in Chinese patients. Methods In the Sir Run Run Shaw Hospital between 1994 and 2003, 379 patients were diagnosed as IBD. Demographic and clinical data were collected and analysed. Results Of 379 patients, 317 had ulcerative colitis (UC) (83.6%, 168 male, 149 female, male-female ratio 1.13∶1, age range at diagnosis 14-79 years, mean age 44 years) and 62 had Crohn’s disease (CD) (16.4%, 39 male and 23 female, male-female ratio 1.70∶1, age range at diagnosis 13-70 years, mean age 33 years). In UC, 11.4% of patients had proctitis, 25.2% had proctosigmoiditis, 18.6% were diseased to the splenic flexure and 44.8% had extensive colitis. Nine patients with UC (2.8%) had arthritis, three patients (0.9%) had iritis or conjunctivitis. Of the 62 CD patients, 16 (25.8%) had diseases restricted to the terminal ileum; 15 (24.2%) had colonic diseases; 20 (32.3%) had ileocolonic disease and 11 (17.7%) had disease involving the upper gastrointestinal tract. Conclusions This study shows similar caracteristics of IBD to that in the West but there are some differences with respect to severity and extraintestinal manifestations. The ethnic and geographic differences may give important clues to the aetiology of IBD.展开更多
文摘The Altay orogenic belt of Xinjiang in NW China represents one of the important sites of juvenile crustal growth during the Phanerozoic. However, some important issues, e.g., tectonic evolution and petrogenesis, still remain controversial. The picrites in the south margin of the Altay orogenic belt were discovered in the lower part of marine volcanic-sedimentary sequences of the northwest-striking Middle Devonian Beitashan Formation (Fm.), which consists chiefly of intermediate-basic volcanic rocks intercalated minor carbonate, siltstone and siliceous rocks. The picrites are usually highly porphyritic, and contain abundant forsteritic olivine phenocrysts with minor clinopyroxene distributed in the groundmass, which consist of olivine, clinopyroxene and plagioclase with minor Fe-Ti oxides. The MgO contents of the picrites range from 14 wt% to 22 wt% with Mg# (atomic Mg/(Mg+Fe) ratio) of 0.75-0.80. They are characterized by slightly negative Ti anomalies, remarkably negative Nb and Ta anomalies and slightly positive P and Sm anomalies with the similar abundances of HFSE as MORB on the MORB-normalized trace element patterns, all of which characterize typical island arc magmas. In combing with the southwestward migration of the magmas of the Beitashan Fm., we propose that the magmas may result from the southwestward subduction of Junggar ocean plate. The Zr/Nb ratios (23-66) of both picrites and basalts resemble the MORB (10-66), suggesting that they were derived from the MORB-like sources. However, the basalts and picrites display some distinguishable element ratios and REE patterns, e.g., Ti/V (23-35) and Zr/Sm (18-23) ratios of basalts are higher than those of picrites (14-17 and 14-15 respectively), and the basalts display flat-type REE-chondrite patterns whereas the picrites are characterized by lower total REE concentrations ((26-34)×10^-6) and slight enrichment of light REE. These distinguished geochemical characteristics could be interpreted by different partial melting degrees and mantle sources, i.e., the basalts were generated by lower partial melting of amphibole-bearing spinel peridotite which was metasomatized by fluids released from subducted oceanic crust, and the picrites were resulted from the higher degree of partial melting of metasomatized garnet peridotite under high temperature. In contrast, the andesite with significant LREE and LILE enrichment may be resulted from the partial melting of eclogites.
文摘Background Numerous studies from Europe and North America have provided a wealth of information regarding the epidemiological and clinical characteristics of inflammatory bowel disease (IBD) in Caucasians. Previous studies in China's Mainland have been limited by small patient numbers or by lack of detailed information about clinical subgroups of the disease. This study was carried out to assess the demographic and clinical characteristics of IBD in Chinese patients. Methods In the Sir Run Run Shaw Hospital between 1994 and 2003, 379 patients were diagnosed as IBD. Demographic and clinical data were collected and analysed. Results Of 379 patients, 317 had ulcerative colitis (UC) (83.6%, 168 male, 149 female, male-female ratio 1.13∶1, age range at diagnosis 14-79 years, mean age 44 years) and 62 had Crohn’s disease (CD) (16.4%, 39 male and 23 female, male-female ratio 1.70∶1, age range at diagnosis 13-70 years, mean age 33 years). In UC, 11.4% of patients had proctitis, 25.2% had proctosigmoiditis, 18.6% were diseased to the splenic flexure and 44.8% had extensive colitis. Nine patients with UC (2.8%) had arthritis, three patients (0.9%) had iritis or conjunctivitis. Of the 62 CD patients, 16 (25.8%) had diseases restricted to the terminal ileum; 15 (24.2%) had colonic diseases; 20 (32.3%) had ileocolonic disease and 11 (17.7%) had disease involving the upper gastrointestinal tract. Conclusions This study shows similar caracteristics of IBD to that in the West but there are some differences with respect to severity and extraintestinal manifestations. The ethnic and geographic differences may give important clues to the aetiology of IBD.
