نتایج جستجو برای: carbon and sulfur stable isotopes

تعداد نتایج: 16921217  

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2013
James D Wright Morgan F Schaller

The Paleocene/Eocene thermal maximum (PETM) and associated carbon isotope excursion (CIE) are often touted as the best geologic analog for the current anthropogenic rise in pCO2. However, a causal mechanism for the PETM CIE remains unidentified because of large uncertainties in the duration of the CIE's onset. Here, we report on a sequence of rhythmic sedimentary couplets comprising the Paleoce...

2004
C. H. Lear Y. Rosenthal H. K. Coxall P. A. Wilson

[1] Paired benthic foraminiferal trace metal and stable isotope records have been constructed from equatorial Pacific Ocean Drilling Program Site 1218. The records include the two largest abrupt (<1 Myr) increases in the Cenozoic benthic oxygen isotope record: Oi-1 in the earliest Oligocene ( 34 Ma) and Mi-1 in the earliest Miocene ( 23 Ma). The paired Mg/Ca and oxygen isotope records are used ...

Journal: :زمین شناسی اقتصادی 0
محمد معانی جو معصومه وفایی زاد فرهاد آلیانی

introduction the ahangaran pb-ag deposit is located in the hamedan province, west iran, 25 km southeast of the city of malayer . . the deposit lies in the strongly folded sanandaj-sirjan tectonic zone, in which the ore bodies occur as thin lenses and layers. the host rocks of the deposit are early cretaceous carbonates and sandstones that are unconformably underlain by jurassic rocks. ore miner...

Journal: :Journal of hazardous materials 2014
Shannon K Hanna Robert J Miller Hunter S Lenihan

Carbon nanotubes (CNTs) are one of the few truly novel nanomaterials and are being incorporated into a wide range of products, which will lead to environmental release and potential ecological impacts. We examined the toxicity of CNTs to marine mussels and the effect of mussels on CNT fate and transport by exposing mussels to 1, 2, or 3mg CNTsl(-1) for four weeks and measuring mussel clearance ...

Journal: :Science 1982
E M Druffel

Radiocarbon analyses and stable isotope measurements are presented foro recent cores of banded corals from the Florida Straits. These values provide a record of variations in the ratio of carbon-14 to carbon-12 in the dissolved inorganic carbon in the surface waters of the Gulf Stream from A.D. 1642 to 1800. An increase in the carbon-14/carbon-12 ratio of 7 per mil for coral growth during the e...

2012
Theodore J. Weller Craig A. Stricker

Bats are known to roost in redwood forests year-round, but their activities outside the summer season are poorly understood. To improve understanding of the use of redwoods by resident and migrant bats, we conducted 74 mist net surveys between February 2008 and October 2010. Captures were dominated by Yuma myotis (M. yumanensis) in the summer and silverhaired bats (Lasionycteris noctivagans) in...

Journal: :Global and planetary change 1990
J C Walker

Climate is an important environmental parameter of the early Earth, likely to have affected the origin and evolution of life, the composition and mineralogy of sedimentary rocks, and stable isotope ratios in sedimentary minerals. There is little observational evidence constraining Precambrian climates. Most of our knowledge is at present theoretical. Factors that must have affected the clima...

2013
J.-J. Cao

An intensive investigation of carbonaceous PM2.5 and TSP (total suspended particles) from Pudong (China) was conducted as part of the MIRAGE-Shanghai (Megacities Impact on Regional and Global Environment) experiment in 2009. Data for organic and elemental carbon (OC and EC), organic species, including C17 to C40 n-alkanes and 17 polycyclic aromatic hydrocarbons (PAHs), and stable carbon isotope...

Journal: :Isotopes in Environmental and Health Studies 2021

The application of organic fertilizers (OF) can supply carbon (C) to the soil in crop fields. OF-derived C (OF-C) is often estimated using differential method that be biased due indirect effects OF on C. This study tested three methods quantify OF–C: (i) widespread method, (ii) synchronic isotope comparing plots with and without (iii) asynchronic mimicking a trial control plot. These were imple...

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