نتایج جستجو برای: geochemical profile

تعداد نتایج: 232683  

Journal: :Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 2020

2010
YAN-JIE TANG HONG-FU ZHANG JI-FENG YING

Lithium isotopes have many advantageous characteristics as geochemical tracers for a wide range of geological processes, covering fluid/melt-mineral interactions from the Earth’s surface to the mantle. The latest developments in Li isotope geochemistry, in terms of measuring techniques, major geochemical reservoirs, the contrasting behaviors during near-surface weathering, and crust/ mantle cyc...

Journal: :iranian journal of science and technology (sciences) 2006
s. alipour

lag is a general term applied to coarse grained (> 2 mm), hard, but partially weathered rockfragments, which are concentrated at the surface through attrition of finer materials. based on morphology,mineralogy and the origin of lag from the cobar region of australia, lag may be conveniently grouped intothree broad morpho-mineralogical categories; (a) those with a rough, blocky, lithic morpholog...

2014
Brandon Lee Drake Wirt H. Wills Marian I. Hamilton Wetherbee Dorshow

Strontium isotope sourcing has become a common and useful method for assigning sources to archaeological artifacts.In Chaco Canyon, an Ancestral Pueblo regional center in New Mexico, previous studiesusing these methods have suggested that significant portion of maize and wood originate in the Chuska Mountains region, 75 km to the West [corrected]. In the present manuscript, these results were t...

2015
Lei Dou Tingting Li L. Dou T. T. Li

Soil heavy metal pollution is one of the main environmental problems in Pearl River Delta Economic Zone of China. Based on multi-purpose regional geochemical survey, regional eco-geochemical assessment, local eco-geochemical assessment and comprehensive appraisal, the eco-geochemical survey and assessment in Pearl River Delta Economic Zone of 41,698 km2 were completed. Samples from soils were c...

2004
Alireza Panahi Qiuming Cheng Graeme F. Bonham-Carter

Combined geostatistical and multifractal power-spectrum modelling of geochemical distributions can provide suitable indicators of metal dispersion, and is capable of analysing complex problems for targeting potential areas for mineral exploration. A case study analysing lake sediment geochemical data for the Gowganda area is presented and development of the methodology for spatial analysis of t...

Journal: :Geobiology 2013
J Huang X Chu T W Lyons N J Planavsky H Wen

Acanthomorphic acritarch fossils, including some interpreted to be the fossils of the earliest animal embryos, first appear in the lower Doushantuo Formation of the Yangtze Gorges area (YGA). Further, the complete paleontological and geochemical record for the YGA has played a central role in defining the global biological and geochemical backdrop that presaged and witnessed the dawn of diverse...

2014
Pincelli M. Hull Peter J. S. Franks Richard D. Norris

47 The interpretation of the Cretaceous-Paleogene (K-Pg) iridium anomaly – and other 48 impact ejecta – as the result of a single, large asteroid impact has been the subject of much 49 debate, in part due to the distribution of impact markers beyond the narrow confines of the K-Pg 50 boundary sedimentary layer. Here, we revisit the hypothesized processes leading to the shape of 51 K-Pg iridium ...

2016
Robert E. Danczak Steven B. Yabusaki Kenneth H. Williams Yilin Fang Chad Hobson Michael J. Wilkins

Citation: Danczak RE, Yabusaki SB, Williams KH, Fang Y, Hobson C and Wilkins MJ (2016) Snowmelt Induced Hydrologic Perturbations Drive Dynamic Microbiological and Geochemical Behaviors across a Shallow Riparian Aquifer. Front. Earth Sci. 4:57. doi: 10.3389/feart.2016.00057 Snowmelt Induced Hydrologic Perturbations Drive Dynamic Microbiological and Geochemical Behaviors across a Shallow Riparian...

2011
Chaosheng Zhang Ya Tang Xianli Xu Ger Kiely

It is challenging to perform spatial geochemical modelling due to the spatial heterogeneity features of geochemical variables. Meanwhile, high quality geochemical maps are needed for better environmental management. Soil organic C (SOC) distribution maps are required for improvements in soil management and for the estimation of C stocks at regional scales. This study investigates the use of a g...

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