... 2 O contents. Nevertheless, the geochemical composition of these rocks remained the same, and in trace-element composition (La/Yb, K/La, Rb/La, and La/Cs) they are close to A -type magnesian andesites from Adak Island (Central Aleutians). Geochemical data suggest that there is no genetic...

... C. (1985) . Seismicity associated with a cluster of earthquakes of m b ≧ 4.5 near Adak, Alaska: evidence for an asperity? Bull. Seism. Soc. Am. 75 , 223 - 236 . Das S. Kostrov...

...James R. Hein; Hsueh-Wen Yeh; John A. Barron Abstract Bedded quartz cherts that contain recognizable diatoms are rare in the geologic record and are described here for the first time. The Eocene Andrew Lake Formation on Adak Island, Alaska consists of about 800 m of sedimentary and volcanogenic...

.... (1979) . Tectonic implications of seismicity in the Adak Canyon region, central Aleutians , Bull. Seism. Soc. Am. 69 , 1515 - 1532 . Minster J. B. Jordan T. H...

... with a cluster of earthquakes of m b ≧ 4.5 near Adak, Alaska: evidence for an asperity ? Bull. Seism. Soc. Am. 75 , 223 - 236 . Byrkit D. R. (1980) . Elements of Statistics , 3rd ed. , D. van Nostrand Company , New York , 482 pp...

...J. Roger Bowman; Carl Kisslinger Abstract An area of the main thrust zone south of Adak, Alaska, in the central Aleutian island arc is characterized by clustering of hypocenters of earthquakes of m b ≧ 4.5 and by low b -value relative to the rest of the thrust zone. The location and dimension...

...Frank Scherbaum; Carl Kisslinger Abstract On 6 May 1984, a m b = 5.8 earthquake occurred within a subregion of the Adak Seismic Zone that had shown clustering of m b >4.5 earthquakes during the last 3 yr. This region has been examined for premonitory variations in stress drop and apparent...

...Thomas Toth; Carl Kisslinger Abstract A technique suggested by Hales et al. (1981) for determining hypocentral depths that are relatively independent of the velocity model originally used to locate the earthquakes is applied to a carefully selected set of earthquakes located with the Adak Seismic...

...G. P. Citron; R. W. Kay; S. Mahlburg Kay; L. W. Snee; J. F. Sutter Abstract Six biotite and two hornblende separates from the Hidden Bay pluton, Adak Island, yielded K-Ar dates that cluster about an average of 33.13 ± 0.41 m.y. B.P. This average is interpreted as the time of intrusion of the pluton...

...R. LaForge; E. R. Engdahl abstract Adak local-network and teleseismically recorded data are used to describe shallow seismicity and tectonics in the Adak Canyon region of the central Aleutians. An examination of the locations and focal mechanisms of earthquakes up to 50 km in depth, occurring...

...DAVID W SCHOLL; H. GARY GREENE; MICHAEL S MARLOW Abstract In 1948, several specimens identified as the plant genus Annularia, a primitive horsetail of Pennsylvanian or Permian age, were found in tuffaceous sandstone exposed near the northern end of Adak Island, Alaska. These beds form the basal...

... by Robert R. Coats of the U.S. Geological Survey in tuffaceous sandstone exposed near Andrew Lake, northern Adak Island, Alaska. Because of the geographic position of these upper Paleozoic fossils near the middle of the Aleutian insular chain, it has been a challenging if not a vexing problem to fit...

...RICHARD B PERRY; HAVEN NICHOLS Abstract Bathymetric analysis of hydrographic data taken in the region of Adak Canyon on the southern slope of the Aleutian Ridge off Alaska indicates that the canyon is a distinct and important boundary between an essentially regular, convex slope to the east...

... to publication of this analysis of their map, and to Professor John C. Griffiths for his very helpful advice. © 1961 American Association of Petroleum Geologists 1961 American Association of Petroleum Geologists Introduction .—Adak and Kagalaska Islands, in the Aleutians, have been studied...

...ROBERT R COATS Abstract Samples of 17 volcanic rocks of Tertiary and Quaternary age from Adak and Kanaga islands have been chemically analyzed and studied microscopically. Spectrograms have been made of 10 of them. The rocks from Adak represent one center of possibly older Tertiary age and two...

...Vedanta Adak; Upama Dutta Abstract Partial equilibrium textures such as corona provide information on changing pressure–temperature ( P - T ) conditions experienced by a rock during its geological evolution. Coronae layers may form in single or multiple stages; understanding the genesis of each...

...Amit Adak; Durjoy Mallik; Swapan Khandra; Swades K. Chaudhuri GeoRef, Copyright 2004, American Geological Institute. 1999 ...