Standards for electron probe microanalysis of silicates prepared by convenient method

Standard compositions suitable for electron probe microanalysis of various silicates are prepared by coprecipitation of specified salts with colloidal silica to form a gel which is decomposed into a powdered oxide mixture and compressed into thin pellets. These pellets of predetermined standard are compared with a silicate sample to determine its composition

Lower Mississippian Lithostratigraphy, Northern Arkansas

Lower Mississippian lithostratigraphic units in northern Arkansas are (ascending order) the Bachelor, St. Joe, and Boone Formations. These formations disconformably overlie Middle Ordovician to Upper Devonian strata and are overlain disconformably by Meramecan or Chesterian strata. The Bachelor Formation is generally a thin (less than 0.3 m), persistent, orthoquartzitic sandstone with common to abundant phosphatic pebbles overlain by a green silty shale. In northwestern Arkansas, the Bachelor Formation commonly lacks sandstone. The Bachelor Formation has been confused previously with the Sylamore (Upper Devonian) and older sandstone units. Although commonly regarded as a member of the Boone Formation, the St. Joe Limestone should be raised to formation rank in accordance with the earlier proposal of Cline (1934). The St. Joe Limestone in northwestern Arkansas can be subdivided into (ascending order) the Compton, Northview, and Pierson Members which are recognized as formations in Missouri. In the type region, northcentral Arkansas, subdivision of the St. Joe is precluded by lack of the shaly Northview Member. A marked color change from gray to red from northwestern to northcentral Arkansas is accompanied by a general increase in the allochemical constituents. The St. Joe Boone boundary is taken to be at the first persistent chert. This contact generally coincides with a thin calcareous shale unit and a marked decrease in carbonate grain size

Volatilization-fractionation of silicates related to chondrite composition

The compositions of chondritic meteorites are linked to the solar composition. It is believed that the chemistry of the (generally) drop-shaped chondrules which comprise a large portion of these meteorites may present valuable clues to their formation and, ultimately, to the early conditions and processes of the planets. The purpose of this experiment is to determine the nature of volatilization-fractionation of silicate (and related metallic) compositions related to chondrite composition

RESOURCE ALLOCATION AND DECISION ANALYSIS FOR AGRICULTURAL RESEARCH

Research and Development/Tech Change/Emerging Technologies,

Merit Selection of Judges in Alaska: The Judicial Council, The Independence of the Judiciary, and the Popular Will

The judicial selection and retention provisions of the Alaska Constitution, found in Article IV, achieve a delicate and remarkably successful balance between competing interests. The purposes of this article are to describe this constitutional plan (called “merit selection” because it begins with nomination based on merit alone), explain why the founders adopted it, examine historical challenges to it, and assess its performance on the 60th anniversary of Alaska statehood