QUATERNARY RESEARCH 29, 196191 (1988)

BOOK REVIEWS

Rates of Chemical Weathering of Rocks and Min- erals. Edited by S. M. Colman and D. P. Dethier. Ac- ademic Press, Orlando, FL, 1986, 603 pp.

This collection of 23 papers deals with processes and rates of silicate chemical weathering on time scales of a few years to about 10’ yr. Broadly, two perspectives are represented by the various contribu- tors: that of the geochemist or soil scientist, focused on details of chemical processes, mineralogical changes during weathering, and hydrochemistry; and that of the Quatemary geologist, focused on using ob- servations of weathering phenomena and inferences about rates to solve chronological and stratigraphic problems in the field. The book is divided into five parts: (I) kinetics of weathering reactions; (II) rates of mineral alteration in soil environments; (III) weather- ing of volcanic ashes and deposits; (IV) rates of for- mation of rock weathering features; and (V) hydro- chemical studies of rates of weathering. The odd- numbered sections have a geochemical focus, the even-numbered ones a Quatemary-geology focus. Al- though the editors state in the preface that they “so- licited current, mostly unpublished, work,” up to a third of the papers are primarily reviews, such as those by Nahon (“Evolution of iron crusts in tropical landscapes”), Ugolini (“Processes and rates of weath- ering in cold and polar desert environments”), and Lowe (“Controls on the rates of weathering and clay mineral genesis in airfall tephras”).

A point made obvious by the arrangement of papers is the great disparity in methodology between the two groups of contributors. In general, the geochemists pay closer attention to physical processes and compli- cations in determining mass balances during weather- ing, complications that may significantly affect esti- mates of weathering rates. The Quatemary geologists tend to focus on statistical methods, using measure- ments of features such as weathering rinds, mineral- grain etching, mineral abundance ratios, or seismic properties to develop dating techniques. Of this latter group, the authors of only two papers (Crook and GiIlespie and Whitehouse et al.) made more than a cursory mention of processes controlling weathering features. One disagreement that came to light among the Quatemary geologists involved the usefulness and utility of mineral-abundance ratios as a measure of weathering. Hall and Martin rejected the notion that

hornblende abundance as a function of depth in tills at their study sites was due to depletion by weathering. Instead, they argued that variations in hornblende abundance reflected variations in petrology of the till parent material. On the other hand, Mahaney and Hal- vorsen argued that variations of mineralogy with depth reflected differential weathering.

The primary criticism that can be leveled at this book is that it lacks a unified perspective on rates of chemical weathering. This may be due to a lack of interaction between the “geochemical” camp and the “Quatemary” camp, although papers from both are presented. The primary benefits of this book are two- fold: (1) it allows the reader to compare and contrast the approaches of workers in different disciplines, all of whom are interested in either processes or effects of weathering, and (2) it provides a useful guide for work- ers intending to pursue weathering studies focused on either geochemistry or Quatemary geology. By pre- senting “state of the art” summaries, future investiga- tors will be challenged to examine these approaches critically and develop new ones.

J. S. WALDER

Quarternary Research Center, University of Washington, Seattle, Washington 98195

Pollen of The High Andean Flora, Province of Men- doza, Argentina. By Monica Wingenroth and C. J. Heusser. Instituto Argentino de Nivologia y Glaciolo- gia (IANIGLA), Mendoza, 1985, 195pp., $45.00.

Given the substantial logistical and administrative obstacles that must have been faced in publishing in Argentina such a high-quality compendium of regional pollen micrographs this book represents an admirable effort. Seventy-four pollen taxa from 27 families are illustrated by scanning and light-microphotographs of highest photographic and reproductive quality. Ac- companying the photos are morphological descriptions and size measurements, cross references to other sources of illustration, pollenmorphological keys, a glossary of terms, and an index. Most of the pollen types reproduced represent taxa included in an illus-

190 0033-5894188 $3.00 Copyright 0 1988 by the University of Washington. All tights of reproduction in any form reserved.

BOOK REVIEWS 191

trated flora, by M. Wingenroth and J. Suarez, pub- lished by IANIGLA in 1984. Although the selected taxa probably represent only a small part of the high Andean flora, and in addition are from primarily in- sect-pollinated plants which will rarely find their way into sediments and fossil pollen preparations, the vol- ume is undoubtedly a valuable contribution. Pollen flo- ras are used not only for paleopalynological studies, but also in context of plant taxonomy, plant evolution, and pollination research, which justifies that this book

reaches a wide audience outside the Quatemary spe- cialists working in South America.

Available through Centralizado de Documentation y Information, Casilla de Correo 131, 5500 Mendoza, Argentina

VERA MARKGRAF

Instituie of Arctic and Alpine Research University of Colorado

Boulder, CO 80309