K-rich lamellar exsolution in clinopyroxene： Constraint on the depth of peridotite source at Zhimafang

The oriented lamellar K-rich exsolutions within clinopyroxene host were recognized in garnet peridotite massif at Zhimafang in the Sulu ultrahigh pressure metamorphic terrane, eastern China. EMP and TEM analyses revealed that the composition and the index of electron diffraction for this exsolution are corresponding with phlogopite, and the shape is the lamellae with 1 μm in width and 5 to 30 μm in length. Moreover, the topotaxy is that the (001) of K-rich exsolution parallels to (I00) of the clinopyroxene host. The electron diffraction analyzing shows the exsolution is of a 1M polymorphism. The high-resolution lattice fringe image displays the stack features along [001], which only a layer mineral shows. We conclude that the clinopyroxene with IM and K-rich exsolution was probably derived from mantle depths over 240 km, thus resulting from decompressional exsolution in the initial stage of slab exhumation.     

采用固体发酵与微生物浸出相结合利用白云鄂博富钾板岩的方法

为了解决白云鄂博地区富钾板岩资源生态化利用的问题,采用固体发酵与微生物浸出相结合的方法对富钾板岩的利用进行了研究.研究发现,可以同时制备出固体和液体两种肥料.肥效验证结果表明,液体与固体肥料均能显著提高番茄种子的发芽率及发芽势,MDA施肥在西红柿生长期间的各个时间段都显著低于MDA不施肥,说明所生产肥料可显著提高番茄的生长效率并可增加其抗损伤能力,证明用微生物分解白云鄂博地区富钾板岩制备复合肥料是生态、环保、可行的方案.     

Derivation of P–T paths for Middle–Late Triassic very low-grade metapelite from Hongcan Well 1 in the Zoigê Depression and their tectonic implications

Using XRD measurements of illite crystallinity,b0values of K-rich white micas and chemical compositions of chlorites combined with homogenization temperatures of fluid inclusions in calcite,the metamorphic P–T conditions of very low-grade metapelites from different depths in the 7 km Hongcan Well 1 in the Zoige?Depression,Sichuan,China,have been obtained in this paper.Knowledge of the tectonic evolution of the studied basin allows us to derive geothermal curves for Middle and Late Triassic time(the geothermal peak)and the present day(from thermal logging of the borehole).The retrograde P–T tracks from clockwise P–T–t loops have been revealed by the plotting of individual samples on each geotherm,which can be interpreted by the lithospheric thickening due to sedimentation and folding followed by continuous uplift and erosion.A stratigraphic log indicates that the Well penetrates the steep limb of a fold which perturbed the peak geotherm and caused some P–T paths to cross.