نتایج جستجو برای: microfossil

تعداد نتایج: 309  

Journal: :Geochemical Transactions 2006
M Ivarsson

Doubly polished thin sections, originally prepared for fluid inclusion studies, present great advantages in the study of microfossils in volcanic rocks. Better visibility and light conditions, variation in thickness of the thin sections and the possibility to combine fluid inclusion studies with microfossil studies lead to a wide range of advantages over ordinary thin sections. This includes th...

2005
NOHEMI SALA-BURGOS ROBERTO GIL-PITA

Microfossils are very important in order to establish terrain correlations, allowing to determinate the age of geological layers with a high grade of accuracy. They are also the fund of any micropaleontological studies. Actual techniques used to extract microfossils are manual, and require of a high amount of time and human resources. This fact make interesting the study of other more complex t...

1994
John P. Oakley Richard T. Shann Darryl N. Davis Laurent Hugueville

The Manchester Content Addressable Image Database is ageneric tool which has been designed for image informatics and computer vision problems. The system stores pre-compuied feature tokens, which are obtained by conventional processing of the input images, into a database which is accessed by a specialised query language (M VQL [1 ]). The M VQL is based on the creation and refinement of groups ...

2017
Emmanuelle J. Javaux Kevin Lepot

The Paleoproterozoic (2.5-1.6 Ga) Era is a decisive time in Earth and life history. The paleobiological record (microfossils, stromatolites, biomarkers and isotopes) illustrates the biosphere evolution during a time of transitional oceanic and atmosphere chemistries. Benthic microfossil assemblages are recorded in a variety of oxygenated, sulfidic, and ferruginous environments representative of...

Journal: :Image Vision Comput. 1992
John P. Oakley Richard T. Shann

A new class of oriented, curvature sensitive filters are introduced. These filters provide a low-level detection facility for noisy curves without a prior edge extraction stage. The application of these filters to the detection of Carboniferous Foraminifers (a type of microfossil found in plane rock sections) is described. A symbolic representation of the detected curves is stored in a database...

2000
Mark B. Edlund Eugene F. Stoermer

Siliceous microfossil succession was analyzed in a 200,000-yr sediment sequence recovered from the Buguldeika Saddle in Lake Baikal, Russia. Siliceous microfossil abundance varied among core depths from no preserved microfossils during inferred colder climate conditions to recent interglacial sediments containing over 300 3 106 microfossils per g dry sediment. Depth-age microfossil assemblage z...

2004
C. Meyer

As part of the international cooperative Baikal Drilling Project, siliceous microfossil assemblage succession was analyzed in two short (~ 30-cm) sediment cores from Lake Baikal. One core was recovered from the north basin (Core 324, 55°15~N, 109°30~E), a second from between the central and southern basins (Core 316, 52°28'N, 106°5rE). The northern core had higher amounts of biogenic silica (40...

2013
Takeshi Nakagawa Hiroyuki Kitagawa Rebecca Payne Pavel Tarasov

Using standard samples is a simple yet very effective method to control data quality. In the field of Quaternary science, it is a commonly applied approach for isotope and geochemical analyses, greatly increasing the general level of confidence in these analytical methods. Microfossil analysis, by contrast, does not normally have any such system to secure data precision and accuracy objectively...

Journal: :Earth-Science Reviews 1966

2017
Kevin Lepot Ahmed Addad Andrew H Knoll Jian Wang David Troadec Armand Béché Emmanuelle J Javaux

Problematic microfossils dominate the palaeontological record between the Great Oxidation Event 2.4 billion years ago (Ga) and the last Palaeoproterozoic iron formations, deposited 500-600 million years later. These fossils are often associated with iron-rich sedimentary rocks, but their affinities, metabolism, and, hence, their contributions to Earth surface oxidation and Fe deposition remain ...

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