During the 1:50000 regional geological survey in Jimo,east Shandong Province,Paleoproterozoic metamorphic supracrustal rocks and Neoproterozoic metamorphic plutonite were newly discovered.These rocks displayed inclusi...During the 1:50000 regional geological survey in Jimo,east Shandong Province,Paleoproterozoic metamorphic supracrustal rocks and Neoproterozoic metamorphic plutonite were newly discovered.These rocks displayed inclusions which had occurred in the Mesozoic granite,and the main lithologies are schist,granulite,marble,and granitic gneiss.Geochemical analyses suggest that Neoproterozoic metamorphic plutonite are characterized by high-K,metaluminous to weakly peraluminous.They are enriched in LILE and depleted in HFSE,with moderately enrichment of LREE,weak fractionation of LREE from HREE and negative Eu anomalies.The surface age of plutonic rocks in the survey area is 770.2±2.4 Ma,representing the age of magma crystallization,which is agreement with the the Neoproterozoic magmatic event after Rodinia supercontinent in the northern margin of Southern China continental block.In addition,the age of sporadic distribution(298 Ma and 269 Ma)is mixed zircon age,representing the rocks experienced metamorphism in Indosinian period.According to the associated mineral assemblages,and the characteristic metamorphic minerals and temperature pressure conditions,four metamorphic facies were identified,including amphibolitic,epidote amphibolite,greenschist,and mid-high pressure greenschist.Analysis of tectonic setting suggests that granitic gneiss is formed in an extensional environment and was involved from the continental margin magmatic arc to intraplate environment.Jimo is distributed in the east of Zhuwu fault,and has the same Spatial distribution location with the Weihai uplift UHP metamorphic belt rocks.The metamorphic rocks in Jimo area have similar geochemical characteristics of elements,tectonic setting and retrograde metamorphism with that in the Sulu UHP metamorphic belt.Therefore,Zhuwu fault may be the boundary fault of Sulu UHP metamorphic belt.展开更多
The Jimo coast encompasses an area of 2157 km^2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting o...The Jimo coast encompasses an area of 2157 km^2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting of 15 functional ecological groups was developed for the coastal ecosystem using the Ecopath model in Ecopath with Ecosim(Ew E) software(version 6.4.3). The results of the model simulations indicated that the trophic levels of the functional groups varied between 1.0 and 3.76, and the total production of the system was estimated to be 5112.733 t km^(-2) yr^(-1) with a total energy transfer efficiency of 17.6%. The proportion of the total flow originating from detritus was estimated to be 48%, whereas that from primary producers was 52%, indicating that the grazing food chain dominated the energy flow. The ratio of total primary productivity to total respiration in the system was 3.78, and the connectivity index was 0.4. The fin cycling index and the mean path length of the energy flow were 4.92% and 2.57%, respectively, which indicated that the ecosystem exhibits relatively low maturity and stability. The mixed trophic impact(MTI) procedure suggested that the ecological groups at lower trophic levels dominated the feeding dynamics in the Jimo coastal ecosystem. Overfishing is thought to be the primary reason for the degeneration of the Jimo coastal ecosystem, resulting in a decline in the abundance of pelagic and demersal fish species and a subsequent shift to the predominance of lower-trophic-level functional groups. Finally, we offered some recommendations for improving current fishery management practices.展开更多
基金funded by Natural Science Foundation of China(41502064)Natural Science Foundation of Shandong Province(ZR2015JL016)+2 种基金Land and resources survey project of China Geological Survey(1212011120749)the National Geological Survey Project(1212010811029)the Scientific Research Foundation of Shandong University of Science and Technology(2014RCJJ012)
文摘During the 1:50000 regional geological survey in Jimo,east Shandong Province,Paleoproterozoic metamorphic supracrustal rocks and Neoproterozoic metamorphic plutonite were newly discovered.These rocks displayed inclusions which had occurred in the Mesozoic granite,and the main lithologies are schist,granulite,marble,and granitic gneiss.Geochemical analyses suggest that Neoproterozoic metamorphic plutonite are characterized by high-K,metaluminous to weakly peraluminous.They are enriched in LILE and depleted in HFSE,with moderately enrichment of LREE,weak fractionation of LREE from HREE and negative Eu anomalies.The surface age of plutonic rocks in the survey area is 770.2±2.4 Ma,representing the age of magma crystallization,which is agreement with the the Neoproterozoic magmatic event after Rodinia supercontinent in the northern margin of Southern China continental block.In addition,the age of sporadic distribution(298 Ma and 269 Ma)is mixed zircon age,representing the rocks experienced metamorphism in Indosinian period.According to the associated mineral assemblages,and the characteristic metamorphic minerals and temperature pressure conditions,four metamorphic facies were identified,including amphibolitic,epidote amphibolite,greenschist,and mid-high pressure greenschist.Analysis of tectonic setting suggests that granitic gneiss is formed in an extensional environment and was involved from the continental margin magmatic arc to intraplate environment.Jimo is distributed in the east of Zhuwu fault,and has the same Spatial distribution location with the Weihai uplift UHP metamorphic belt rocks.The metamorphic rocks in Jimo area have similar geochemical characteristics of elements,tectonic setting and retrograde metamorphism with that in the Sulu UHP metamorphic belt.Therefore,Zhuwu fault may be the boundary fault of Sulu UHP metamorphic belt.
基金the financial support provided by the National Social Science Foundation (Grant No.12JJD790032)the Project of the Chinese Ministry of Education (Grant No.13JJD790032)
文摘The Jimo coast encompasses an area of 2157 km^2, and the ecosystem is valuable both socially and economically with regional fisheries substantially contributing to the value. A mass-balanced trophic model consisting of 15 functional ecological groups was developed for the coastal ecosystem using the Ecopath model in Ecopath with Ecosim(Ew E) software(version 6.4.3). The results of the model simulations indicated that the trophic levels of the functional groups varied between 1.0 and 3.76, and the total production of the system was estimated to be 5112.733 t km^(-2) yr^(-1) with a total energy transfer efficiency of 17.6%. The proportion of the total flow originating from detritus was estimated to be 48%, whereas that from primary producers was 52%, indicating that the grazing food chain dominated the energy flow. The ratio of total primary productivity to total respiration in the system was 3.78, and the connectivity index was 0.4. The fin cycling index and the mean path length of the energy flow were 4.92% and 2.57%, respectively, which indicated that the ecosystem exhibits relatively low maturity and stability. The mixed trophic impact(MTI) procedure suggested that the ecological groups at lower trophic levels dominated the feeding dynamics in the Jimo coastal ecosystem. Overfishing is thought to be the primary reason for the degeneration of the Jimo coastal ecosystem, resulting in a decline in the abundance of pelagic and demersal fish species and a subsequent shift to the predominance of lower-trophic-level functional groups. Finally, we offered some recommendations for improving current fishery management practices.
