نتایج جستجو برای: geochemical

تعداد نتایج: 12072  

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...

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...

Journal: :Environmental science & technology 2006
M W Fields C E Bagwell S L Carroll T Yan X Liu D B Watson P M Jardine C S Criddle T C Hazen J Zhou

Few studies have demonstrated changes in community structure along a contaminant plume in terms of phylogenetic, functional, and geochemical changes, and such studies are essential to understand how a microbial ecosystem responds to perturbations. Clonal libraries of multiple genes (SSU rDNA, nirK, nirS, amoA, pmoA, and dsrAB) were analyzed from groundwater samples (n = 6) that varied in contam...

Journal: :international journal of mining and geo-engineering 0
samaneh safari shahrood university of technology mansour ziaii shahrood university of technology maliheh ghoorchi ferdowsi university of mashhad

singularity based on fractal and multifractal is a technique for detection of depletion and enrichment for geochemical exploration, while the index of vertical geochemical zonality (vz) of pb.zn/cu.ag is a practical method for exploration of blind porphyry copper mineralization. in this study, these methods are combined for recognition, delineation, and enrichment of vz in jebal- barez in the s...

2002
W. W. Shilts

and Vagners (1971, 1972) expressed this phenomenon elegantly by introducing the concept of "terminal mode" for the optimum grain size to which a mineral can be reduced, given the force and energy typically available in the glacial environment. Thus, hard, uncleaved or poorly cleaved minerals such as quartz, fcldspar, garnet, pyrite and magnetite dominate either the medium or the fine sand fract...

2017
Christophe Thomazo Jean-Francois Buoncristiani Emmanuelle Vennin Pierre Pellenard Theophile Cocquerez Jean L. Mugnier Emmanuelle Gérard

Citation: Thomazo C, Buoncristiani J-F, Vennin E, Pellenard P, Cocquerez T, Mugnier JL and Gérard E (2017) Geochemical Processes Leading to the Precipitation of Subglacial Carbonate Crusts at Bossons Glacier, Mont Blanc Massif (French Alps). Front. Earth Sci. 5:70. doi: 10.3389/feart.2017.00070 Geochemical Processes Leading to the Precipitation of Subglacial Carbonate Crusts at Bossons Glacier,...

2008
S. Sestak P. F. Greenwood

Is UV laser ablation a suitable tool for geochemical analysis of organic rich source materials? Conference Item How to cite: Sestak, Stephen; Watson, Jonathan S.; Sherlock, Sarah; Greenwood, Paul F. and Fuentes, David (2008). Is UV laser ablation a suitable tool for geochemical analysis of organic rich source materials? In: 15th Australian Organic Geochemistry Conference, 8-12 September, Adelaide.

The most significant aspect of a geochemical exploration program is to define and separate the anomalous values from the background. In the past decades, geochemical anomalies have been identified by means of various methods. Most of the conventional statistical methods aiming at defining the geochemical concentration thresholds for separating anomalies from the background have limited the effi...

2008
K. G. McQueen

Geochemical anomalies are geochemical features different from what is considered normal. They can be the result of: 1. unusual or uncommon processes concentrating particular elements (e.g. an ore-forming process, weathering and element dispersion from an unusual element concentration such as an orebody); 2. element accumulation or concentration by common processes acting over long periods (e.g....

نمودار تعداد نتایج جستجو در هر سال

با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید