Samples were systematically collected from metamorphic basic volcanic rocks in the Jiehekou and Xiyupi areas on both sides of the L黮iang Mountains, Shanxi Province and analyzed for their major elements, trace elements and rare earth elements (REE). The geochemical charac-teristics of their major, trace and rare-earth elements indicated that the metamorphic basic volcanic rocks in this area were emplaced in the tectonic environment like a modern continental rift. Sm-Nd and Rb-Sr isotope chronological studies demonstrated that the Jiehekou Group metamorphic basic volcanic rocks were formed during the 2600-Ma crust/mantle differentiation event, and were trans-formed by granulite facies metamorphism during the late Neo-Archaean period (2500 Ma ?, mak-ing the Sm-Nd systematics of the rocks reset. During the late Paleoproterozoic period (1800 Ma ? the Rb-Sr systematics of the rocks were disturbed again in response to the L黮iang movement. Since the extent of disturbance was so weak that the Sm-Nd systematics was not affected, the age of 1600 Ma obtained from this area seems to be related to local magmatic activities within the craton. Research results lend no support to the idea that the L黮iang Group was formed during the Archaean. Instead, it should be formed during the Proterozoic.
The regional observed temperature and precipitation changes and their abrupt jumps disturbed by large-scale reclamation in the Sanjiang Plain,Northeast China were studied. Mean annual temperature of the region was tending to go up and has increased by 1.2-2.2℃ over the past 50 years. A warming jump of mean annual temperature of the region occurred in the 1980s,which had an increase amplitude of 0.9℃. Linear tendency rates of annual precipitation were negative in most of the region. The maximum of annual precipitation decrease was 155.8mm over the past 50 years. An abrupt decrease of regional annual precipitation happened in the middle of the 1960s,which had a decrease of 102.1mm. Based on the fact of climatic change of the Sanjiang Plain over the past 50 years,it is held that the region had larger warming amplitude than that of the surrounding areas in the recent years,which resulted from the large-scale reclamation of various kinds of wetlands.
We studied oviposition sites and their effects on the reproductive success of the Chinhai salamander (Echinotriton chinhaiensis) .The results showed that: (1) the female had strong preferences for spawning sites and oviposition microhabitat; (2) the most suitable oviposition sites were 30 cm higher than water level and 45 cm from the water body; (3) oviposition sites usually overlapped;(4) embryos could develop and hatch normally in water as well as on land. The hatching rate on land was high (94 3%), but the number of hatchlings that successfully migrated to water was low (52%±11%, n =3 in the laboratory, and approximatly 20% in nature). Based on the situation in laboratory, the average hatchling survival rate at all oviposition sites was 36 7%. Owing to oviposition on land, the reproductive success of Chinhai salamander was very low;(5) protecting the spawning sites and increasing the hatchling survival rate are the keys to conserving this species.
