摘要:

We distinguish three major detachment systems and intervening accommodation zones in the central Gregory Rift of east Africa and point out that the geometry seen here is similar to that of other modern and ancient continental rift systems. The asymmetry of the rift (half‐graben form) alternates along the rift axis, with corresponding reversals in the polarity of the extensional detachment systems. This may be important to the overall understanding of rift tectonics, as the Gregory Rift is associated with an unusually voluminous volcanogenic province, regional doming, and other characteristics of continental “hot spots” (and their inferred subcontinental mantle plumes). The fact that all continental rifts appear to have very similar structural geometries, yet few are actually associated with these hot spot characteristics supports the contention that hot spots are only locally associated with and do not significantly affect the shallow geometry of continental ri

ISSN:0002-8606    

DOI:10.1029/EO067i029p00577

年代:1986

数据来源: WILEY

摘要:

The Cascade Mountain Range, which consists of a series of Quaternary and late Tertiary andesitic volcanos that extend from Northern California to Southern British Columbia, is a geologic province with immense potential for the generation of electricity from geothermal energy resources. The geothermal potential for the Cascades Province may well be thousands if not tens of thousands of megawatts [seeBloomquist et al., 1985]. Yet to date there are no geothermal power plants operating in the Cascades Province, and none are planned. Furthermore, except for the obvious heat sources represented by the active volcanos, very little is known about the geothermal resources in the Cascades.

ISSN:0002-8606    

DOI:10.1029/EO067i029p00578

年代:1986

数据来源: WILEY

摘要:

During the 6 years that I have been privileged to be an officer of the AGU Volcanology, Geochemistry, and Petrology section (VGP) there have been a number of noteworthy changes in the section and its activities. The most important of these was the initiation of the VGP Award (1985 recipients were Wesley Hildreth, Richard Fisher, and Hans‐Ulrich Schmincke), the beginning of the VGP/Planetology luncheons, the “founding” of The VGP News (now under the able leadership of editor John Eichelberger), and the renewal of a sustained effort to forward first‐rate nominees for possible election as Fellows of the Union. These items were covered in some detail in my last report (Eos, April 23, 1985, p. 187), and I will not reiterate. In that report, I also noted that VGP is one of the fastest growing sections in the Union (now nearly 12% of the AGU membership) and one of the most active at the national meetings, as measured by the number of abstracts submitted. Those trends continued through the past year and are indicators of the overall strength of the

ISSN:0002-8606    

DOI:10.1029/EO067i029p00580-01

年代:1986

数据来源: WILEY

摘要:

On June 17, 1986, a continuously cored hole was completed in Long Valley Caldera, approximately 2 km northeast of the town of Mammoth Lakes, Calif. The primary purpose of the hole is to provide access for periodic measurement of the thermal gradient, pressure, and chemistry of water in the thermal aquifer of the caldera's southwestern moat. The hole also investigates the geothermal energy potential in the vicinity of Mammoth Lakes. Core and fluid samples will be available for study by interested scientists.

ISSN:0002-8606    

DOI:10.1029/EO067i029p00582-01

年代:1986

数据来源: WILEY

摘要:

Several scientists of the Brazilian Institute for Space Research (Instituto de Pesquisas Espacias, or INPE; headquarters at Sāo Jose dos Campos, Sao Paulo) went to Manaus (3°S, 60°W), in the central region of the Amazon forest during July–August 1985 to study the atmosphere of the equatorial rainforest. The expedition to the Amazon was part of a large binational atmospheric chemistry field campaign that was organized to measure several atmospheric gases of the forest environment. This was definitely the largest scientific field expedition in this field ever performed on Brazilian terri

ISSN:0002-8606    

DOI:10.1029/EO067i029p00583-01

年代:1986

数据来源: WILEY

摘要:

In the first half of this century, geologists began mapping the islands within the Pacific basin systematically, following the exploratory expeditions launched by major countries in the previous century. Into the remote oceanic expanses went Thomas A. Jaggar, Ruy H. Finch, Howel Williams, Harry S. Ladd, J. Edward Hoffmeister, Gordon A. Macdonald (to name only a few)—and Harold T. Stearns. These were the days of long ship travel without the convenience of airplanes. Cultural mixing had not resulted in the nearly homogenous amorphism that seems to exist now, and communication within and across the basin was slow and tediou

ISSN:0002-8606    

DOI:10.1029/EO067i029p00584

年代:1986

数据来源: WILEY

摘要:

Plate tectonics provides a unifying framework for understanding a wide range of geological processes, and thermal convection in the mantle drives plate tectonics. Thus an understanding of mantle convection is fundamental to the earth sciences. Many fundamental questions concerning mantle convection remain the subject of controversy. Examples include layered versus whole‐mantle convection and the form of secondary convection pattern

ISSN:0002-8606    

DOI:10.1029/EO067i029p00587

年代:1986

数据来源: WILEY