桑江考辨

桑江是宋代著名地理学名著《岭外代答》记述的广西静江府境内的一条重要河流。由于后代史籍记述的缺失,而使一些人认为它是指今天的浔江(宋称王江)龙胜县境内段(今亦称龙胜河),其实历史上真正的桑江应该是指宋代义宁县桑江寨所处位置旁的河流,即今天临桂县义江旧义宁县境段。

南宋中晚期江淮战区的空间调整与李全之乱

南宋宁宗、理宗之际,国防形势发生巨大变化,为此南宋调整了相关战区的防务部署。就江淮战区而言,在嘉定十二年将江淮防务一分为三,并将淮东制置司的治所放在极边之地楚州。这样一种空间结构虽然也取得了一些积极成果,却导致南宋政府坐视李全发动叛乱而无力阻止。随着李全之乱愈演愈烈,南宋政府不得不再次对江淮防务的空间结构作出调整。宝庆三年,淮东制置司放弃楚州,建阃扬州;绍定三年九月,置江淮制置大使,合江淮防务为一。这一调整很快即见成效,绍定四年正月,李全被擒杀,李全之乱平定。

Songjianghe biotite monzonitic granite zircon U-Pb geochronology and geochemical significance

The authors studied geochronology and geochemical data of the Songjianghe biotite monzogranite in the southern Zhangguangcai Range in order to determine its formation age,magma source,and tectonic environment. The results indicate that the Songjianghe biotite monzogranite was formed in the Middle Jurassic with an age of 168. 2 ± 2. 0 Ma( MSWD = 0. 93). The monzogranite was characterized by high alkali and low Ca O and Mg O,belonging to high-potassium calc-alkaline,metaluminous I-type granite. The rock is enriched in large ion lithophile elements such as Rb,Ba,and K and strongly depleted high field strength elements such as P,Ti,Nb,and Ta. It is concluded that the Songjianghe biotite monzogranite was derived from partial melting of amphibolite facies metamorphism mafic lower-crust and its formation was controlled by the Pacific Plate subduction.

Discovery of the Indosinian aluminum A-type granite in Zhejiang Province and its geological significance

Zircon LA-ICP-MS U-Pb dating of the Jingju syenogranites in the southwestern part of Zhejiang Province shows that these rocks were crystallized in the Late Triassic at 215±2 Ma, rather than in the Cretaceous as previously proposed. The Jingju sy- enogranites are characterized by relatively high K2O and FeO＊, and low MgO. They have high concentrations of large ion lithophile elements （LIL） and LREE, such as K, Th, La, and Ce, but are depleted in high field strength elements （HFSE） such as Nb, Ta, and Ti. Their 104Ga/A1 ratios and （Zr＋Nb＋Ce＋Y） contents are also high. These characteristics are similar to those of A-type granites. The syenogranites have high Isr （0.7179-0.7203）, low eNa（t） （from --14.2 to --13.2）, and relatively old T2DM ages, similar to those of the ancient metamorphic basement in the Cathaysia Block. It is suggested that the Jingju syenogranites were formed by partial melting of the Cathaysia basement rocks during tectonic extension. This identification of Indosinian A-type granite in Jingju has significant implications for understanding the early Mesozoic tectonic evolution of South China.

Zircon SHRIMP U-Pb geochronology of the Neoproterozoic Chengjiang Formation in central Yunnan Province(SW China) and its geological significance

The Chengjiang Formation is the earliest continental clastic deposit after the Jinning Orogeny in central Yunnan Province,and therefore its accurate depositional age is significant for understanding the formation and evolution of the Neoproterozoic rift basins in southern China.However,hampered by accuracy of the dating technique,the existing age data for the Chengjiang Formation are not very reliable.A large number of magmatic zircons were obtained from the tuff interbed in the lower part of the Chengjiang Formation in Jinyang area and the bottom part of the Chengjiang Formation in Dongchuan area,central Yunnan Province,and high-precision SHRIMP U-Pb dating was carried out on these zircons.The results show that the weighted mean 206 Pb/238 U ages are 797.8±8.2 and 803.1±8.7 Ma respectively.In combination with related geological evidence,it has been demonstrated that the bottom boundary age of the Chengjiang Formation should be 800±5 Ma,whereas the top boundary age could be ca 725 Ma.By synthetically analyzing the latest age data for the relevant strata,it has been confirmed that the Chengjiang Formation should be correlated with the Suxiong Formation and the Kaijianqiao Formation in western Sichuan Province,the Liantuo Formation in the middle and lower Yangtze,the Hongchicun Formation and the Shangshu Formation in northern Zhejiang Province,the Puling Formation in southern Anhui Province,the Luokedong Formation and the Majianqiao Formation in northwestern Jiangxi Province,the Wuqiangxi Formation in northwestern Hunan Province,the Fanzhao Formation and the Qingshuijiang Formation in southeastern Guizhou Province,and the Sanmenjie Formation and the Gongdong Formation in northern Guangxi Province.Sedimentary cycle analysis shows that the sedimentary filling sequence of the Neoproterozoic rift basins in southern China can be divided into four cycles.Among them,Cycle II began at ca.800 Ma,accompanied by intensive tectonic-thermal events.The zircon U-Pb ages from the bottom of the Chengjiang Formation reported in this paper indicate that the Neoproterozoic Kangdian rift subbasin probably started to develop at ca.800 Ma and therefore missed Cycle I of the Neoproterozoic sedimentary filling sequence in southern China.

A Superior Way for the Transforming China： The Ultimate Ideal or a Feasible Solution？

The restoration of political radicalism in China can be attributed to a number of factors; similarly, the successful construction of a civil society to un- tangle the mess caused by the transformation does not rely on spontaneous fulfill- ment of the society itself, for it involves more factors than have been realized and discussed, such as the state （i.e., the government）, the ruling party, society, and the context of globalization. Without a comprehensive study on the cause of this problem, any prescriptive suggestion or discussion on how to go beyond radicalism is no more than an idealistic path for China＇s political reconstruction.