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This study examined the stable carbon isotope13 (8 C) and characterization of sources of organic matter from core samples of sandstones of mid-Siwalik group Dhok Pathan Formation from Surghar- Shingar Range of NW Himalayan foreland Fold-and-Thrust-Belt. These sediments have recorded valuable information regarding the palaeo-vegetation type and paleo-environment/depositional environments. The analytical results of stable carbon isotope range from -24.50 to -28.43% with an average value of -26.56%. These values correspond to C3 vegetation of cool growing season and support the hypothesis of the dominance of C3 biomass in the ecosystem during the late-Miocene in this area. The phytoclasts are characterized as huminite/vitrinite, derived from terrestrial plants and referred to as type-III kerogen. The fungal attack, scaring and pitting of bacterial activity, biochemical degradation, replacement/diagenetic development of pyrite suggest that these sandstones of Dhok Pathan Formation were deposited under dyoxic conditions and thus these sandstones are primary reduced sandstones.

The aim of this study was to evaluate Hg distribution in mangrove plants and changes of Hg content during leaf aging; the contribution of litterfall to Hg enrichment in mangrove ecosystems is also discussed. Contents of total Hg (THg) and methylmercury (MeHg) in mangrove plants and sediments were determined. Contents of THg and MeHg in the sediments were 225 ± 157 ng/g and 0.800 ± 0.600 ng/g. Concentrations of THg and MeHg in the mangrove plants were 1760 ± 1885 ng/g and 0.721 ± 0.470 ng/g (dry weight), respectively, which were much higher than those in terrestrial plants. Enrichment of THg in mangrove plants was different, following the order Rhizophra apiculata > Rhizophora stylosa > Kandelia candel > Aegiceras corniculatum > Avicennia marina; while MeHg contents in mangrove plants decreased in the order of R. stylosa > K. candel > A. corniculatum > R. apiculata > A. marina. There were obvious interspecies differences, regional differences, individual differences and tissue differences between THg and MeHg contents of mangrove plants, all of which were closely related to the environmental and the physiological characteristics of mangrove plants. In juvenile leaves, mature leaves and leaf litter, THg contents ranged 55.3–1760 ng/g, 204–1800 ng/g, and 385–2130 ng/g (dry weight), respectively; MeHg contents ranged 0.17–2.39 ng/g, 0.01–1.28 ng/g, and 0.13–1.47 ng/g (dry weight), respectively. Except for A. corniculatum and Bruguier gymnorrhiza, THg content of mature leaves was always higher than that in juvenile leaves, but MeHg showed a contrasting trend. THg content of litter leaves was between that of juvenile leaves and mature leaves, while MeHg content was generally lower than that of juvenile leaves and mature leaves. In the mangrove ecosystem, Hg enrichment contributed by the litterfall decreased in the order of K. candel > A. corniculatum > A. marina.

The Dajiangping pyrite deposit located in the middle sector of the Yunkai uplift in western Guangdong is a stratiform sulphide deposit occurring in Sinian marine clastic and fine clastic rocks. The formation of the deposit was related to submarine exhalation and hot brine deposition. A part of it was reformed by late-stage hydro thermal solution. The δ34S values of pyrite vary from — 25.55‰ to + 21.07‰, which are inversely proportional to the content of organic carbon in ore and pyrite. Passing from striped fine-grained pyrite ore to massive coarse-grained pyrite ore, i.e. from south to north, the sulphur isotopic composition changes from the light sulphur-enriched one to the heavy sulphur-enriched one. The lead isotopic composition of striped ore is consistent with that of the country locks of orebodies and the lead is radiogenic lead derived from the upper crust. The lead isotopic composition of massive ore is relatively homogeneous and its 206/Pb204Pb, 207/Pb204Pb and 208/Pb204Pb ratios are a bit lower than those of striped ore; the lead result from mixing of synsedimentary ore lead with that derived from basement migmatite brought by late-stage hydrothermal solutions.

Indium occurs in a very dispersed manner in nature with enrichment of economic interest rarely known. The highly dispersed nature of indium, among several other elements, has for a long time retarded our understanding of the regularities that control their mineralization, which in turn has hindered exploitation and application of these elements. Recent studies of ours show that no significant enrichment of indium can be recognized in various types of Pb-Zn sulphide deposits as well as in deposits of copper, iron and manganese. Indium concentrations in ores of these deposits are generally below 10 × 10-6. In contrast, however, indium is found to be enriched to a significant extent in cassiterite-sulphide deposits and some tin-rich Pb-Zn polymetallic deposits. The average content of indium in these deposits can be over 100 × 10-6, and more than 90% of it is concentrated in sphalerite. Generally, these deposits may be considered as large paragenic deposits for indium and, therefore, there must be some regularities that govern the geochemical enrichment of the so-called “dispersed element” indium.