Earth Sciences Commons^™

The Global Stratotype Section And Point (Gssp) For The Base Of The Katian Stage Of The Upper Ordovician Series At Black Knob Ridge, Southeastern Oklahoma, Usa, Daniel Goldman, Stephen A. Leslie, Jaak Nõlvak, Seth Young, Stig M. Bergström, Warren D. Huff

Geology Faculty Publications

The International Subcomission on Ordovician Stratigraphy (ISOS) of the International Commission on Stratigraphy (ICS) recently defined the base of the global Upper Ordovician Series to be at the first appearance datum (FAD) of the graptolite species Nemagraptus gracilis in the Fågelsång GSSP in southern Sweden. This designation recognized the tremendous utility for global correlation of the first appearance of a cosmopolitan taxon that occurs within a consistent succession of other first appearance datums (e.g., Finney and Bergström, 1986; Bergström et al., 2000). Current efforts by the ISOS have focused on subdividing the Upper Ordovician into three stages and choosing appropriate …

1991: Pinatubo Eruption, Monish Ranjan Chatterjee

Electrical and Computer Engineering Faculty Publications

Date: June 12-16, 1991

Place: Luzon, Philippines

Result: About 350 dead (mostly from collapsed roofs); extensive damage to homes, bridges, irrigation-canal dikes, and cropland; 20 million tons of sulfur dioxide spewed into the stratosphere up to an elevation of 15.5 miles

Prior to the 1991 eruption, Pinatubo had the appearance of a steep, domelike spheroid that rose about 2,297 feet (700 meters) above a gently sloping apron made of pyroclastic and epiclastic materials. Such a volcano belongs to the class of stratocones, of which such 803 well-known exemplars as Fuji and Mayon are considerably larger than Pinatubo. The extensive pyroclastic …