نتایج جستجو برای: stratigraphic boundary

تعداد نتایج: 163281  

1998
A. T. BASILEVSKY J. W. HEAD

The details of stratigraphic units and structures making up six coronae and their regional surroundings on Venus were examined using full resolution Magellan images and stereoscopic coverage. Altimetry and stereoscopic coverage were essential in establishing the local stratigraphic relationships and the timing of corona-related topography. The degree of preservation of signatures of earlier cor...

Journal: :Journal of theoretical biology 2018
Tanja Stadler Alexandra Gavryushkina Rachel C M Warnock Alexei J Drummond Tracy A Heath

A birth-death-sampling model gives rise to phylogenetic trees with samples from the past and the present. Interpreting "birth" as branching speciation, "death" as extinction, and "sampling" as fossil preservation and recovery, this model - also referred to as the fossilized birth-death (FBD) model - gives rise to phylogenetic trees on extant and fossil samples. The model has been mathematically...

2006
Philip D. Gingerich Margaret Schoeninger

Fossils provide the only direct evidence of the evolutionary history of primates. A method of phylogeny reconstruction is outlined which is based on an evaluation ofphenetic resemblances of fossils interpreted in their stratigraphiccontext. This stratopheneti¢ approach to phylogeny involves three successive steps: (1) organization of fossils stratigraphically, (2) phenetie linking of similar fo...

2013
M. A. Speece Richard Levy D. M. Harwood Stephen F. Pekar R. D. Powell

America). By drilling, coring and analyzing stratigraphic. By drilling, coring and analyzing stratigraphic By drilling, coring and analyzing stratigraphic By drilling, coring and analyzing stratigraphic y drilling, coring and analyzing stratigraphic archives along the Antarctic continental margin, ANDRILL , ANDRILL pursues its primary goal of better understanding the role the primary goal of be...

2010
Kathryn E. Fishbaugh Christine S. Hvidberg Shane Byrne Patrick S. Russell Kenneth E. Herkenhoff Mai Winstrup Randolph Kirk

[1] This study achieves the first high‐spatial‐resolution, layer‐scale, measured stratigraphic column of the Martian north polar layered deposits using a 1m‐posting DEM. The marker beds found throughout the upper North Polar Layered Deposits range in thickness from 1.6 m–16.0 m +/− 1.4 m, and 6 of 13 marker beds are separated by ∼25–35 m. Thin‐layer sets have average layer separations of 1.6 m....

2015
Adam J. Griggs Siwan M. Davies Peter M. Abbott Mark Coleman Adrian P. Palmer Tine L. Rasmussen Richard Johnston

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...

1995
Mark W. Martin Douglas Walker

Stratigraphic correlations presented here for the ductilely deformed and metamorphosed rocks exposed in the Shadow Mountains indicate that they formed on the North American continental margin and are not exotic or significantly displaced from their site of origin. These strata represent a depositional history that spans Late Proterozoic and Paleozoic passive margin development, late Paleozoic t...

2006
M. Parent R. Martel R. Lefebvre Martin Ross

Introduction. Integration of stratigraphic reconstructions and hydrogeologic applications represents a significant challenge. In recent years, different geomodeling tools (e.g., gOcad, EarthVision) and approaches have been developed to provide solutions to this particular problem. One of those solutions is to build computer-based three-dimensional (3-D) geologic framework models (GFM) made of i...

2001
Dieter Mader Alessandro Montanari Christian Koeberl Robert Handler Rodolfo Coccioni

A nearly complete and undisturbed Miocene carbonate sequence is present in the easternmost part of the UmbriaMarche basin, Italy, which is ideal for detailed and integrated stratigraphic investigations of the Miocene Epoch. In this study, we were trying to obtain evidence for the presence or absence of distal ejecta from the 15 Ma Ries impact structure in southern Germany, located about 600 km ...

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