نتایج جستجو برای: element deposits
تعداد نتایج: 231488 فیلتر نتایج به سال:
Localized tephra deposition in marine sequences is the product of many complex primary and secondary depositional processes. These can significantly influence the potential applicability of tephra deposits as isochronous marker horizons and current techniques, used in isolation, may be insufficient to fully unravel these processes. Here we demonstrate the innovative application of X-ray microto...
We determined model ages of mare deposits on the farside of the Moon on the basis of the crater frequency distributions in 10-meter-resolution images obtained by the Terrain Camera on SELENE (Selenological and Engineering Explorer) (Kaguya). Most mare volcanism that formed mare deposits on the lunar farside ceased at approximately 3.0 billion years ago, suggesting that mare volcanism on the Moo...
Measuring value and interest rate risk in retail financial markets such as the market for consumer deposits has proven to be a very difficult problem for financial firms. Standard models of value and interest rate risk (duration), based on the competitive market paradigm, are inappropriate in retail markets characterized by sluggish price and quantity behavior. Although the penetration of sophi...
Efforts to identify alternative sources of energy have focused on extracting natural gas from vast shale deposits. The Marcellus Shale, located in western New York, Pennsylvania, and Ohio, is estimated to contain enough natural gas to supply the United States for the next 45 years. New drilling technology-horizontal drilling and high-volume hydraulic fracturing of shale (fracking)-has made gas ...
Magnetite is a representative ore mineral found in various deposits. The trace element composition of deposits controlled by several physiochemical factors such as temperature, pressure, and oxygen or sulfur fugacity. chemical behavior Germanium (Ge) distinct different environments. Consequently, the patterns Ge magnetite can be used to infer provenance conditions. This study focuses on from Wu...
This paper critically compares the use of laboratory tests against in situ combined with numerical seepage modeling to determine hydraulic conductivity natural soil deposits. Laboratory determination used constant head permeability and oedometer on undisturbed Shelby tube block samples. The auger hole method Guelph permeameter were performed field. Groundwater table elevations deposits differen...
Anjirch Pb-Zn deposits are located 55 km wesl of Esrahan. These deposits belong 10 a part of a large sedimenta ry basin containing lead ttnd zinc metal epieiences, in Sanand aj - Si rjan zone. This basin contains Lower CretO:tceous (Albian - Abtian) sedimentary sequences. The Anjireh deposits are typical of Mississippi-valley type stratttbound lead-zinc deposits. The principal metal miner...
Abstract Pyrite geochemistry has proven useful for tracking changes in the composition and physico-chemical conditions of hydrothermal fluids ore-forming environments. Here, we investigated microtextural features chemical pyrite, a main Au-bearing phase Akeshi Kasuga deposits (Southern Kyushu, Japan), to better constrain processes these high-sulfidation epithermal Au deposits. Despite widesprea...
An open-access database has been set up to support the research project studying the ‘Response of Humans to Abrupt Environmental Transitions’ (RESET). The main methodology underlying this project was to use tephra layers to tie together and synchronise the chronologies of stratigraphic records at archaeological and environmental sites. The database has information on occurrences, and chemical c...
The size frequency distributions of beta-amyloid (A beta) and prion protein (PrPsc) deposits were studied in Alzheimer's disease (AD) and the variant form of Creutzfeldt-Jakob disease (vCJD) respectively. All size distributions were unimodal and positively skewed. A beta deposits reached a greater maximum size and their distributions were significantly less skewed than the PrPsc deposits. All d...
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