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Yao Y.-F.,CAS Institute of Botany | Bruch A.A.,Senckenberg Institute | Cheng Y.-M.,Geological Museum of China | Mosbrugger V.,Senckenberg Institute | And 2 more authors.
PLoS ONE | Year: 2012

Yuanmou Basin of Yunnan, SW China, is a famous locality with hominids, hominoids, mammals and plant fossils. Based on the published megaflora and palynoflora data from Yuanmou Basin, the climate of Late Pliocene is reconstructed using the Coexistence Approach. The results indicate a warm and humid subtropical climate with a mean annual temperature of ca. 16-17°C and a mean annual precipitation of ca. 1500-1600 mm in the Late Pliocene rather than a dry, hot climate today, which may be due to the local tectonic change and gradual intensification of India monsoon. The comparison of Late Pliocene climate in Eryuan, Yangyi, Longling, and Yuanmou Basin of Yunnan Province suggests that the mean annual temperatures generally show a latitudinal gradient and fit well with their geographic position, while the mean annual precipitations seem to be related to the different geometries of the valleys under the same monsoon system. © 2012 Yao et al. Source

Liyong J.,Jilin University | Jun C.,Jilin University | Jun C.,Key Laboratory of Evolution of Past Life and Environment in Northeast Asia | Shuqin Z.,Geological Museum of China | And 2 more authors.
Journal of Vertebrate Paleontology | Year: 2010

The Quantou Formation of Jilin Province, People's Republic of China, has recently yielded an important new fauna of 'middle' Cretaceous vertebrates. This fauna includes the small-bodied cerapodan ornithischian dinosaur Changchunsaurus parvus, represented by excellent cranial and postcranial material. When initially described, Changchunsaurus was hypothesed to represent one of the most basal known ornithopods; however, similarities to ceratopsians were also noted, suggesting that Changchunsaurus may be crucial to elucidating the interrelationships of basal cerapodans, one of most problematic areas of ornithischian phylogeny. Here we present a detailed description of the craniodental anatomy of Changchunsaurus, rediagnose the taxon based upon three autapomorphies, and provide comparisons to other basal cerapodans, as a foundation for future studies of basal cerapodan relationships. Changchunsaurus shows strong similarities to the Chinese Early Cretaceous cerapodan Jeholosaurus, and it is likely that they are sister taxa. © 2010 by the Society of Vertebrate Paleontology. Source

Zeng G.,Nanjing University | Chen L.-H.,Nanjing University | Hu S.-L.,Nanjing University | Xu X.-S.,Nanjing University | Yang L.-F.,Geological Museum of China
Geochemistry, Geophysics, Geosystems | Year: 2013

Although peridotite xenoliths are common in alkaline basalts, it is still unclear whether the chemical compositions of their host rocks have been affected by these mantle fragments and, if so, what processes are involved in this alteration of the host basalts. Here, we document a kind of xenolith-rich alkaline basalts from the Nanjing basaltic field, eastern China. These basalts contain lower concentrations of CaO (4.1-7.8 wt %) and Sc (3.3-17.8 ppm) and have lower Ca/Al (0.3-0.6) and higher Na/Ti ratios (2.8-11.2) than other Cenozoic basalts in this area. These xenolith-rich basalts show good correlations between elemental ratios (e.g., Lu/Hf and Ca/Al) and εHf values, which are indicative of mixing of two distinct components during the genesis of the magmas that formed these basalts: a high-εHf end-member (with low Lu/Hf and Ca/Al ratios) and the primitive melt-related low-εHf end-member. In addition, peridotite xenoliths hosted in these basalts have distinct core-mantle textures, with the margins having higher modal olivine abundances (70%) than the xenolith cores (52%). Within the xenolith margins, some orthopyroxenes are enclosed in the olivines, and all clinopyroxenes are sponge textured. These sponge-textured clinopyroxenes have higher CaO and Sc concentrations, higher Ca/Al ratios, and lower Na/Ti ratios than clinopyroxenes within the cores of the xenoliths, suggesting that the xenoliths underwent low-pressure melting within the host magma. This indicates that xenolith-rich magmas within the study area were contaminated during ascent by melts derived from mantle xenoliths within the magmas, transforming the magmas into the low-Ca alkaline basalts. © 2013. American Geophysical Union. All Rights Reserved. Source

Zhang Z.,Geological Museum of China | Schneider J.W.,TU Bergakademie Freiberg | Hong Y.,Beijing Museum of Natural History
Journal of Systematic Palaeontology | Year: 2013

The most ancient known roach, Qilianiblatta namurensis gen. et sp. nov. from the earliest Pennsylvanian (Namurian B/C) Qilianshan entomofauna, is described from material excavated in the Qilianshan Mountains of north-western China. The new genus is characterized by a mosaic of plesiomorphic and apomorphic features typical of various Euramerican and Angaran Late Palaeozoic blattid genera. Despite a limited time gap between the age of Q. namurensis and that of the previously known oldest blattids (archimylacrids of Westphalian A age, 1-2 Ma younger), the pattern of main veins and cross venation of Q. namurensis appears in some regards more advanced. This is particularly apparent in the only weakly expressed primary dichotomy of main veins and the relatively modern aspect of the cross venation. The new taxon raises questions regarding the polyphyletic origin of the 'phyloblattoid' groundplan, namely once in the Euramerican biotic province at the end of the Westphalian and stemming from archimylacrids, and earlier in the Cathaysian (-Angaran?) biotic province from forms like Qilianiblatta. Forewings of Q. namurensis are clearly protective wings (tegmina) and probably were not involved directly in the production of lift during flight. These wings are considerably advanced relative to the earliest diversification of the winged insects and the general groundplan for hexapodan wings. It is possible that winged blattids appeared as early as the Devonian. © 2013 Natural History Museum. Source

Lu L.S.,Geological Museum of China | Mao J.W.,Chinese Academy of Geological Sciences | Zhou Z.H.,Chinese Academy of Geological Sciences | Li H.B.,Geological Museum of China | And 2 more authors.
Acta Petrologica Sinica | Year: 2012

Systematic studies on the mineralogy of the ore-bearing ultramafic rocks from the Hongqiling Nos.1 and 7 intrusions in east Jilin Province show that the rocks mainly consist of chrysolite, bronzite, clinopyroxene, plagioclase, hornblende and phlogopite. These minerals were crystallized from magma at different depths. In particular, olivine and pyroxene are the best rock-forming minerals that crystallized firstly from the primary magma and could be used to trace the magma, which were derived from the upper mantle. The parental magmas of these intrusions in the intermediate magma chamber are hydrated high-Mg picritic basalt magma and the MgO content were estimated to be about 13.98% and 14.22% with Mg of 72.22 and 71.05 respectively. The depth of the deep-level magma chamber, where only olivine and pyroxene fractional crystallization processes took place ephemerally, was estimated to be about 26 ∼27km. The temperature of magma chamber was 1280 ∼ 1379CC .When magma uplifted from the deep-level to the high-level chamber, this process was nearly adiabatic and completed in a short time. Then, magma maybe experienced double chamber evolutions. Meanwhile, olivine and less pyroxene fractional crystallizations were over before the uplift of magma.But, there was complex process in high-level magma chamber, where crust contamination, mixing with affinal magma and super cooling have been happened. These processes contribute to the increase of ore-forming elements and the saturation of sulfide in the magmatic system, thus Ni-Cu mineralization occurs in the intrusions. Source

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