摘要:

Geochemical and geophysical investigations over the past decade suggest a laterally as well as radially heterogeneous upper mantle. The sources of this variability are mantle dynamics and interactions with the crust. The opportunities to sample these variations directly are limited within continental regions. However, the basalts of the Midcontinent Rift (MCR) System of North America are particularly attractive for studying subcontinental mantle.The MCR is an 1100‐Ma paleorift [Halls, 1978; Green, 1983; Van Schmus and Hinze, 1985] that extends for more than 2000 km across the North American midcontinent (Cover). Drill holes into the MCR to obtain samples of the basalt can be located to answer critical questions regarding the origin and evolution of this aborted Precambrian rif

ISSN:0002-8606    

DOI:10.1029/88EO01238

年代:1988

数据来源: WILEY

摘要:

The Eighth Session of the Intergovernmental Council of the International Hydrological Program (IHP) was held June 21–25 in Paris. Gordon Young of Canada was elected chairman for the next 2 years. The council elected four vice chairmen: Mario C. Fuschini Mejia (Argentina), Riyadh Al‐Dabbagh (Iraq), Umar Kawu (Nigeria), and Slavoljub Jovanovic (Yugoslavia). Anat Arbhabhirama (Thailand), as chairman of the previous council, is a member of the Bureau.Of the 30 council members, 29 attended the meeting. Observers were present from 30 Unesco Member States not council members. The United Kingdom and United States also participated as observers under a ruling of the Unesco Executive Board. Other organizations represented were the African Union for Water Distribution, Arab Federation for Technical Education, Food and Agriculture Organization, Comite Interafricain de Etudes Hydraulique, International Association of Hydraulic Research, International Association of Hydrogeologists, International Association of Hydrologic Sciences, International Atomic Energy Agency, International Committee on Irrigation and Drainage, International Water Resources Association, Palestine Liberation Organization, and World Meteorological Organizat

ISSN:0002-8606    

DOI:10.1029/88EO01245

年代:1988

数据来源: WILEY

摘要:

Most of the contributions in the session Continental Ice Sheets at the AGU Spring Meeting in May in Baltimore dealt with issues relating to the stability of the ice sheets in the face of ongoing or projected future changes. One approach involves monitoring the ice sheet by repeated satellite imagery (Richie Williams and Jane Ferrigno, U.S. Geological Survey, Reston, Va.). This technique will probably reveal the first major changes in sheets due to climatic and other changes.

ISSN:0002-8606    

DOI:10.1029/88EO01248

年代:1988

数据来源: WILEY

摘要:

Often at lectures and seminars we are told just how little is known about a far‐away region on Earth. Such a remark is seldom printed in papers but is implied in bibliographies, which frequently contain very few references to the far place.This is particularly the case for works on countries whose language differs from that of the author. This lack of reference to previous works may be due to the absence of related literature, or to the work's having been reported in local journals of restricted circulation, mostly written in the language of the country, or to the previous work's not being referred to in the bibliography although it was consulted. Not only am I concerned with giving proper credit to previous work, I want also to emphasize that in some instances, limited access to relevant local literature, including unpublished information, may be critical to doing good scienc

ISSN:0002-8606    

DOI:10.1029/88EO01254

年代:1988

数据来源: WILEY

摘要:

There are books and courses on experimental physics, thorough and rigorous, which contain only simple formulae and use only elementary algebra. The subject is explained in lucid and precise language, with the help of many sketches, photos, and diagrams. The book under review belongs to this genre and is in fact one of its most successful members.About half of the book is devoted to the description of a variety of natural phenomena in which gravity currents play an important role. The class of gravity currents is taken to be quite broad, to include almost any kind of quasi‐horizontal motion caused by density differences. The range of natural phenomena surveyed is correspondingly great, from tidal bores through thunderstorms to the eruption of Mount St. Helens. The atmospheric examples are especially thorough and interesting. The broad panorama certainly brings home to the reader the many ways in which fluids (including fluidized rock) can move under the influence of gravity. However, not all of the examples show typical gravity behavior, nor are they all treated with equal thoroughness. The Gulf Stream is mentioned, and the variability of its position is shown in an illustration, but this is not connected with anything typical of gravity currents, nor is the important interplay between Earth rotation and such large‐scale “gravity currents” (if one insists on calling them that) at all adequately ex

ISSN:0002-8606    

DOI:10.1029/88EO01255

年代:1988

数据来源: WILEY

摘要:

world met in March in Bologna at the European Geophysical Society's 13th General Assembly. The meeting sessions were divided among the joint sessions and the three sections of EGS: Section I, Solid Earth and Planets; Section II: Hydrospheres and Atmospheres; and Section III: Upper Atmospheres, Ionospheres, Magnetospheres, and External Geophysics.

ISSN:0002-8606    

DOI:10.1029/88EO01256

年代:1988

数据来源: WILEY