Thermal History of Cambrian Burgess Shale-Type Deposits:New Insights from the Early Cambrian Chengjiang and Qingjiang Fossils of South China

Burgess Shale-type deposits provide a wealth of information on the early evolution of animals.Questions that are central to understanding the exceptional preservation of these biotas and the paleoenvironments they inhabited may be obscured by the post-depositional alteration due to metamorphism at depth and weathering near the Earth’s surface.Among over 50 Cambrian BST biotas,the Chengjiang and Qingjiang deposits are well known for their richness of soft-bodied taxa,fidelity of preservation,and Early Cambrian Age.While alteration via weathering has been well-investigated,the thermal maturity of the units bearing the two biotas has not yet been elucidated.Here we investigate peak metamorphic temperatures of the two deposits using two independent methods.Paleogeotemperature gradient analyses demonstrate that the most fossiliferous sections of the Chengjiang were buried at a maximum depth of∼8500 m in the Early Triassic,corresponding to∼300°C,while the type area of the Qingjiang biota was buried at a maximum depth of∼8700 m in the Early Jurassic,corresponding to∼240°C.Raman geothermometer analyses of fossil carbonaceous material demonstrate that peak temperatures varied across localities with different burial depth.The two productive sections of the Chengjiang biota were thermally altered at a peak temperature of approximately 300°C,and the main locality of the Qingjiang biota experienced a peak temperature of 238±22°C.These results from two independent methods are concordant.Among BST deposits for which thermal maturity has been documented,the Qingjiang biota is the least thermally mature,and therefore holds promise for enriching our understanding of BST deposits.

Molecular Epidemiology of Porcine Circovirus Type 3 Infection in Swine Herds in China

Dear Editor,Porcine circovirus type 3(PCV3)is a new-emerging circovirus belonging to the genus Circovirus in the family Circoviridae in which PCV type 1(PCV1)and PCV type 2(PCV2)were well documented(Palinski et al.2017).PCV1 is a cell culture-derived virus and is considered to be nonpathogenic for swine,whereas PCV2 is the primary etiological agent of porcine circovirus-associated

Impacts of China's Emergence on the World Economy: A Value Chain Perspective

This paper sheds light on the demand-side impact of China’s emergence on the world economy from a value chain perspective. A measure linking final demand with value-added in the context of global value chains is developed. Data from the World Input-Output Database is used to analyze foreign value-added induced by final demand in China. It is found that foreign value-added to meet final demand in China increases over time except during 2008–2009, proving that China has a significant power to shape the world economy through its final demand. Besides, it is found that about88% of foreign value-added is absorbed in China through intermediate imports. In addition, how and to what extend the final demand in China contributes to other countries’ GDP growth is investigated.Results show that continuous increase in foreign value-added absorbed in China becomes a ballooning source of economic growth, and final demand in China is rather a remedy in aftermath of the global recession during 2008–2009. Finally, it is found that the increase in foreign value-added absorbed in China is due not only to the surge in final demand but also to bullwhip effect along global value chains.