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Full-Text Articles in Earth Sciences

The Lower Ordovician Fillmore Formation Of Western Utah: Storm-Dominated Sedimentation On A Passive Margin., Benjamin Dattilo Jul 2014

The Lower Ordovician Fillmore Formation Of Western Utah: Storm-Dominated Sedimentation On A Passive Margin., Benjamin Dattilo

Benjamin F. Dattilo

No abstract provided.


Tempestites In A Teapot? Condensation-Generated Shell Beds In The Upper Ordovician, Cincinnati Arch, Usa., Benjamin F. Dattilo, Carlton E. Brett, Thomas J. Schramm Jul 2014

Tempestites In A Teapot? Condensation-Generated Shell Beds In The Upper Ordovician, Cincinnati Arch, Usa., Benjamin F. Dattilo, Carlton E. Brett, Thomas J. Schramm

Benjamin F. Dattilo

Skeletal concentrations in mudstones may represent local facies produced by storm winnowing in shallow water, or time-specific deposits related to intervals of diminished sediment supply. Upper Ordovician (Katian) of the Cincinnati region is a mixed siliciclastic-carbonate succession including meter-scale cycles containing a shelly limestone-dominated phase and a mudstone-dominated phase. The “tempestite proximality model” asserts that shell-rich intervals originated by winnowing of mud from undifferentiated fair-weather deposits. Thus shell beds are construed as tempestites, while interbedded mudstones represent either fair-weather or bypassed mud. Meter-scale cycles are attributed to sea-level fluctuation or varying storm intensity. Alternatively, the “episodic starvation model” argues, on …


Global Meteorological Drought – Part 1: Probabilistic Monitoring, Will Pozzi Jan 2014

Global Meteorological Drought – Part 1: Probabilistic Monitoring, Will Pozzi

Will Pozzi

Near-real-time drought monitoring can provide decision-makers with valuable information for use in se- veral areas, such as water resources management, or inter- national aid. One of the main constrains of assessing the current drought situation is associated with the lack of re- liable sources of observed precipitation on a global scale available in near-real time. Furthermore, monitoring sys- tems also need a long record of past observations to pro- vide mean climatological conditions. To address these prob- lems, a novel probabilistic drought monitoring methodology based on ECMWF probabilistic forecasts is presented, where probabilistic monthly means of precipitation were derived from …


Locating Cryptotephra In Sediments Using Fluid Imaging Technology, Robert D'Anjou, Nicholas L. Balascio, Raymond S. Bradley Jan 2014

Locating Cryptotephra In Sediments Using Fluid Imaging Technology, Robert D'Anjou, Nicholas L. Balascio, Raymond S. Bradley

Raymond S Bradley

We report a new approach to locate and quantify cryptotephra in sedimentary archives using a continuously-imaging Flow Cytometer and Microscope (FlowCAM_). The FlowCAM rapidly photographs particles flowing in suspension past a microscope lens and performs semi-automated analysis of particle images. It has had primarily biological applications, although the potential sedimentological applications are numerous. Here we test the ability of this instrument to image irregularly shaped, vesicular glass shards and to screen sediment samples for the presence of cryptotephra. First, reference samples of basalt and rhyolite tephra (sieved <63>microns) were analyzed with the FlowCAM, demonstrating the ability of the instrument to …