In order to understand the level and distribution of (220)Rn concentrations in soil-gas in the high-radiation-background area, an (220)Rn survey was carried out for the first time using a RAD7 portable radon monitor at 67 locations covering a total area of 1800 km(2) in the South of China. (220)Rn concentrations were significantly different from that in the surface areas covered by the weathered granite of Yanshan Period or Quaternary sediments. The (220)Rn concentrations varied between 6.65 and 461 kBq m(-3) and the averages were 294.42 ± 81.36 and 23.30 ± 25.84 kBq m(-3) for weathered granite products and sediments, respectively. A high positive correlation between (220)Rn concentrations and (232)Th activity concentrations was found. (220)Rn concentrations had no statistically significant variations from depths of 20-140 cm with an interval of 20 cm. It is worth paying attention to the problem of such a high soil (220)Rn concentration in Zhuhai City and Zhongshan City.

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Early Cretaceous dike swarms are widely developed in the Jiaodong Peninsula, NE China. In this study, we newly investigated the spatial-temporal distribution, petrography, geochronology and whole-rock geochemistry of the intermediate-felsic dikes from the Jiaobei terrain and the Sulu orogenic belt in the Jiadong Peninsula. The zircon U-Pb dating has constrained the timing of the emplacement of intermediate-felsic dikes to 128-108 Ma. The quartz diorite dikes in Jiaobei show adakitic geochemical features, including high SiO 2 (66.3-67.5 wt.%) contents and high Sr/Y (76-149) and La/Yb (41-91) ratios. The combination of a series of isotopic data, including initial 87 Sr/ 86 Sr ratios (0.7098-0.7104) and negative ε Nd (t) (-20.1 to-14.7) and zircon ε Hf (t) values (-19.9 to-9.5), indicates that these quartz diorite dikes were likely derived from partial melting of thickened ancient lower crust with involvement of underplated mafic magmas. Additionally, the diorite dikes in Jiaobei and those in Sulu show similar chemical compositions, as both yield the high-Mg andesite (or andesitic rocks) (HMAs) characteristics with a high Mg # value (60-72), high MgO, Cr, and Ni contents, and low Na 2 O (average = 3.25 wt.%) contents. They also exhibit crustal geochemical signatures, such as depletion in Nb, Ta, and Ti, but enrichment in Th and U; high initial 87 Sr/ 86 Sr ratios (0.7063-0.7094), and low ε Nd (t) (-16.7 to-9.6) and ε Hf (t) values (-29.4 to-9.8). The entire geochemical evidences imply that they derived from the partial melting of mantle wedge peridotite metasomatized by hydrous fluids from the subduction of the oceanic slab with marine sediments. In combination with the Early Cretaceous intrusions and mafic dikes at Jiaodong, the intermediate-felsic dikes represent a magmatic response to lithospheric thinning resulted from the prolonged thermo-mechanical-chemical erosion processes caused

The carboniferous igneous rock in the west Junggar Basin mainly composed of tuff, andesite, basalt and volcanic breccia is very hard to exactly distinguish via geological logging. Based on logging data coupled with cores, logging cross plot, imaging logging and fisher discriminant was used to identify the lithology. The effect of cross plot is too confused to distinguish all the lithology. Imaging logging can effectively visualized divide four types of igneous rock, but time and human resources are essential. Fisher discriminant analysis can integrate several logging information and achieve auto identification, decreasing human resource cost and time consumption. With the combination of three methods, modified lithology section is more abundant in lithology and more accurate in lithology, depth and thickness. The new section can be well useful in reservoir research.

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