http://www.sciencedirect.com/science/article/pii/S1674987113000315

The Panzhihua gabbroic intrusion,part of the plumbing system of the Emeishan large igneous province, intruded late-Proterozoic dolomites and marls about～263 Ma ago.The dolomites in the contact aureole were converted to brucite marbles and a diverse suite of forsterite,diopside and garnet skarns.The variation in mineralogy is explained in part by differences in the composition of the protolith,particularly the proportion of silica minerals and clay,and in part by transfer of elements from intruding magmas.The trace element compositions of most marbles and skarns are very similar to those of unmetamorphosed dolomites and marls,but some contain high Si,Ti,and Fe contents that are interpreted to have come from a magmatic source.Three brucite marbles sampled～10 m from the contact of the intrusion and named "enriched brucite marble" have trace element compositions very different from their dolomitic protolith:their rare earth elements are strongly enriched whereas levels of Nb-Ta,Zr-Hf and Ti are very low.These characteristics resemble those of carbonate liquid in equilibrium with silicate liquid or more probably with silicate minerals in the case of Panzhihua,a similarity we take to indicate that the sample underwent partial melting.Samples taken up to 300 m from the contact contain brucite indicating that high temperatures persisted well into the country rocks.However,other samples collected only tens of metres from the contact are only slightly recrystallized indicating that conditions in the aureole were highly variable.We suggest that temperatures within the aureole were controlled by conduction of heat from the main intrusion and by supply of additional heat from abundant small dykes within the aureole.Circulation of fluids derived from deeper levels in the aureole flushed the carbon dioxide from the dolomite,lowering temperature needed to partially melt carbonate to the temperatures attained near the intrusion.Irregular but extensive heating destabilized the carbonates of the aureole and decarbonation reactions associated with carbonate breakdown and melting emitted a large volume of CO₂,with potential impact on global climate.     

BL Lacertae： Hard Optical Spectrum and GeV γ-ray Emission

The spectral energy distribution (SED) of the γ-ray flare observed in July 1997 in BL Lacertae is re-considered. It is pointed out that the optical observations made by Webb et al. showed the associated optical flare has a hard spectrum (the average spectral index αopt～0.48, Fν∝ν^-α), and the ASCA observations made by Tanihata et al. showed very steep spectra in the soft X-ray band (0.7-1.5 keV) (αx～3-4). We find that the flux densities and spectral indices in both the optical and soft X-ray bands are closely consistent with a ‘canonical‘ synchrotron spectrum emitted by relativistic electrons of a power-law energy distribution with a high energy cutoff, and thus the peak of the SED of the synchrotron radiation (in representation of νFν) is located in the EUV - soft X-ray bands. Therefore, the GeV γ-ray emission observed in the July 1997 outburst may be mainly due to the synchrotron self-Compton (SSC) process, contrasting with the current explanations in terms of external radiation Compton (ERC) process, in which the seed photons are mostly taken to be the UV emission from the clouds of the broad emission line region. We argue that the hard optical spectra observed during the γ-ray outburst may be an important signature for the acceleration of high energy electrons (γe-10^4) in the γ-ray emitting region.     

喜马拉雅的结构和构造——关于地球物理观测的概略小结

喜马拉雅地区的主要结构和构造与岛弧的相似 ,但被轻的印度陆壳 (不是洋壳 )消亡引起的作用所改造。恒河盆地下的前第三纪基底的表面形态与海洋深海槽的表面形态相似 ,而中印高原是外部地形隆起的追忆记载。印度地盾上的重力异常与朝向海洋的岛弧的重力异常相似 ,并具有岩石圈在深海沟处向下弯曲和在外缘隆起处向上挠曲的模式。断裂面的分解式说明印度岩石圈确实弯曲 ,然后以低角度向喜马拉雅山俯冲。来自印度和岛弧的有关这方面的资料说明了同一个现象。大西洋和印度洋的海洋地球物理资料 ,可以对最后 70 Ma的印度和欧亚地质史加以恢复。一种急剧减缩作用 ,速率大致为 1 0 0 mm/ a。大概在 40 Ma前接近或稍晚于地质上所推定的碰撞时间。印度向巨大深处的消亡作用假定为漂浮的大陆壳所阻碍。印度地壳的浮力可能导致收敛速率的降低 ,但不是停止。虽然与新断裂的产生以及印度板片一个个地向上推置 ,形成山脉带有关 ,但地震记录表明 :沿低角底断裂面 (可在主边界断裂上或紧邻主边界断层 )的俯冲断裂作用 ,使敛合作用继续发生。重力异常与这种解释是一致的。假若喜马拉雅是由印度次大陆古老板片北缘的断裂作用和仰冲板片所建立起来的 ,那么与重力资料说明有 30 0— 40 0 km的缩短是一致的。在喜马拉雅山收缩     

Stratigraphy of Upper Cretaceous──Paleogene deposits of northwestern Zeya──Burya sedimentary basin

In the northwestern Zeya──Bureya sedimentary basin, the authors studied coal deposits, including Ivanovsko-Erkovetskyu brown coal square on which is worked off largest Erkovetsky field of brown coal, extending to south flank of the Mesozoic──Cenozoic Belogor'e depression. The verified stratigraphic scheme of the coalfield sedimentary sequence is substantiated by palynological data on core samples from 18 boreholes sampled in the course of detailed prospecting and by paleobotanical analysis of sections in the Yuzhnyi sector of the coalfield. Sections of the Erkovtsy, Arkhara Boguchan, and Raichikha brown-coal mines are correlated. Stratigraphic subdivisions distinguished in the studied sedimentary succession are the middle and upper Tsagayan subformations (the latter incorporating the Kivda Beds), Raichikha and Mukhino formations.     

Late Cenozoic Tectonic Deformation in the Dongsha Islands and Adjacent Sea Area

Dongsha Island and the adjacent sea area locate at the northern continental margin of the South China Sea (SCS), and is connected to the east by the Manila Trench. Analyses of seismic stratigraphy and gravity, magnetic and drilling wells data led to the discovery of three post-fault sequences (Ⅴ, Ⅵ, Ⅶ). Extensive tectonic uplift, magma activity and erosion occurred in Dongsha Island and the adjacent area, where most of the faults in the northeastern SCS were still active during Pliocene and Quaternary. Two groups of faults trending NEE and NW were developed during Late Cenozoic. We conclude that three important tectonic movements, especially Dongsha movement(4.4 - 5.2 Ma) and Liuhua movement (1.4 - 1.89 Ma), controlled the structural framework in the Dongsha rise; whose deformation in the east is stronger than that in the west and whose stress field variation suggests that the tectonic uplift in the study area contributed to magmato-tectonic events correlated to the main collision phases between the East China and Taiwan 5 - 3 and 3 - 0 Ma ago.