نتایج جستجو برای: geochronology

تعداد نتایج: 1891  

Journal: :Marine Pollution Bulletin 2021

The sedimentary environment is a repository and carrier for variety of pollutants, sediment transport from land to coastal areas an important environmental process. In the present study, we use 210 Pb/ 226 Ra 137 Cs in cores assess supply rates at four sites within Vefsnfjord Nordland county, Norway. This area was highly affected by fallout Chernobyl accident 1986 inventories fjord are much hig...

Journal: :Marine pollution bulletin 2009
Anirudh Ram D V Borole M A Rokade M D Zingde

Sequential extraction of Hg was performed in a core collected from intertidal area in Ulhas Estuary in order to characterize the downward distribution and diagenetic behavior of Hg in a polluted estuary. Concentration of total Hg ranged between 0.46 and 6.40 microg g(-1) with significant decrease in surficial sediment as a result of closing of two Hg-cell based chlor-alkali plants. Results of s...

Journal: :Biology letters 2011
Jacqueline M T Nguyen Martyna Molak Karen H Black Erich M G Fitzgerald Kenny J Travouillon Simon Y W Ho

The 13th Conference on Australasian Vertebrate Evolution Palaeontology and Systematics (CAVEPS) took place in Perth, Western Australia, from 27 to 30 April 2011. This biennial meeting was jointly hosted by Curtin University, the Western Australian Museum, Murdoch University and the University of Western Australia. Researchers from diverse disciplines addressed many aspects of vertebrate evoluti...

2015
Josep M. Parés

*Correspondence: Josep M. Parés, Geochronology, Research Center for Human Evolution (CENIEH), Paseo Sierra de Atapuerca 3, Burgos 09006, Spain e-mail: [email protected] The use of the Anisotropy of Magnetic Susceptibility (AMS) has become a rather common practice in Earth Sciences since the pioneer note by Graham (1954). The versatility of the technique, and the rapidness in obtaining and p...

2008
Andrew P. Roberts

[1] Geomagnetic excursions are short-lived episodes when Earth’s magnetic field deviates into an intermediate polarity state. Understanding the origin, frequency, amplitude, duration, and field behavior associated with excursions is a forefront research area within solid earth geophysics. Recent advances in excursion research are summarized here, and key further research is suggested to resolve...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 1994
H M McHenry

The quickening pace of paleontological discovery is matched by rapid developments in geochronology. These new data show that the pattern of morphological change in the hominid lineage was mosaic. Adaptations essential to bipedalism appeared early, but some locomotor features changed much later. Relative to the highly derived postcrania of the earliest hominids, the craniodental complex was quit...

2000
S. R. Hemming E. T. Rasbury

Samples of Fish Canyon and Cobb Mountain sanidine monitor standards, irradiated and fused with 7 W of CO laser 2 power for ArrAr geochronology analyses, give Pb isotope composition and Pb concentrations that are indistinguishable from unprocessed aliquots of the same monitors. The absence of measurable change in Pb isotope composition indicates the feasibility of measuring the Pb isotope compos...

Journal: :Marine pollution bulletin 2011
Andreza P Ribeiro Rubens C L Figueira César C Martins Charles R A Silva Elvis J França Márcia C Bícego Michel M Mahiques Rosalinda C Montone

Admiralty Bay (Antarctica) hosts three scientific stations (Ferraz, Arctowski and Macchu Picchu), which require the use of fossil fuel as an energy source. Fossil fuels are also considered the main source of pollution in the area, representing important inputs of major pollutants (organic compounds) and trace metals and metalloids of environmental interest. Accordingly, this work presents the r...

2010
James D. Gleason Jens Gutzmer Stephen E. Kesler Horst Zwingmann

The known dimensions of hydrothermal fluid circulation associated with emplacement of the 2.055-Ga Bushveld Igneous Complex (BIC) are extended with new isotopic ages for Paleoproterozoic mineral deposits in wallrocks (Transvaal Supergroup) surrounding the BIC. A fluorite-rich Mississippi Valley–type (MVT) deposit in the Zeerust district, dated at 2.05 Ga (Sm-Nd isochron age), has Nd isotopic co...

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