Skip Navigation

September-October 2014

Print
Email
ResizeResize Text: Original Large XLarge

Media Reviews

Roadside Geology of Georgia by Pamela J. W. Gore and William Witherspoon. Mountain Press, Missoula, MT; www.mountain-press.com. 347 pages; 2013; $24 plus postage (softbound).

Roadside Geology of Georgia, the latest addition to the Roadside Geology Series, reflects Mountain Press's recent trend to offer higher quality guides with more information and better illustrations including full-color photos and geologic maps and cross-sections. Authors Pamela J. W. Gore and William Witherspoon have matched the aesthetics of this book with a condensation of their years of research and map-making.

The book is densely packed with accurate and up-to-date information that reflects the varied and complex geology of the Peach State. It is also physically hefty, probably because of the amount of Georgia kaolin (the state's main mineral money-maker) used to coat its pages and provide its glossy appearance.

Producing a geology guide for Georgia had several challenges. First, unlike the arid West, the subtropical southeastern climate produces a heavy mantle of soil (specifically saprolite) and encourages vegetation to quickly cover outcrops. Second, because there are so few decent outcrops, Georgia's geology can be challenging and occasionally quite controversial. (I have personally witnessed several yelling matches on outcrops on field trips.) Going back to the 1980s, there have been two failed attempts to produce such a guide. The wait was worth it, however.

The authors were clearly up to the challenges of Georgia geology. In doing research for the book, they consulted leading experts at regional universities to get the latest advances in the geologic history of Georgia and then successfully summarized that information in understandable terms. A thorough bibliography lists key references used and will be helpful for those seeking more in-depth explanations.

Georgia's geology is best grouped by physiographic province, reflecting a combination of regions of similar rock type and topography. This is the approach used in the organization of this guide. With a brief discussion of geology and plate tectonics, the stage is set. Following common usages, there are four main sections of the guide book: Sea Islands; Coastal Plain; Valley and Ridge and Appalachian Plateau; and Blue Ridge and Piedmont. Each of these in turn begins with a geologic overview of the respective province followed by the road guides. The sections not only contain information on the geology but where appropriate include historic vignettes as well. For example, during the Civil War the geology of northwest Georgia (Valley and Ridge) affected the course of the Atlanta Campaign of 1864. This fascinating connection is explained in a sidebar. Numerous such examples are scattered throughout the book.

For the mineral collector this book will be a valuable resource. Some common minerals and their occurrence are discussed. Graves Mountain is specifically mentioned and its geologic history summarized. Also discussed are some of the metamorphic minerals common to the state: garnet, kyanite, and the state mineral, staurolite. On the subject of state symbols, it is also noted that the shark's tooth is the state fossil. However, there is no mention of the state gem, quartz, which would then have led to a mention of the many fine amethyst locations, including the famous Jacksons Crossroads site. There is a brief section on the pegmatites of the Barnesville-Thomaston district, but nothing is said about other mineralogically significant pegmatite mines (the Cochran, Amphlett, or Hogg mines, for instance). However, this is not a serious criticism because the book is not intended as a guide to mineral sites in the state. It will serve well as a framework for understanding mineral occurrences, though.

As with the crisscrossing network of major Georgia highways, it may take a little flipping back and forth between road guides to catch all of the desired information on a site of interest, but it is all there. My recommendation is for the reader to become familiar with the guide as soon as it is acquired, and then to use the excellent index to find all information on a specific site—not just the information in the road guides—before hitting the road. That will maximize the book's utility. Georgia also contains many beautiful state parks and historic sites, most of which the book covers.

As already noted, the Roadside Geology of Georgia is packed with information. During the book-release lecture in Atlanta, Gore and Witherspoon pointed out that much valuable information had to be edited down to get the book to a manageable size (347 pages). Not wanting to lose this information, they placed the edited information on a webpage (http://georgiarocks.us/) that serves as a repository for ancillary details, interactive maps, and road logs cut from the book. This too is new to the Roadside Guide Series and, although unique to the Georgia guide, could serve as a model for other books in the series.

In summary, this book is well researched, written, and illustrated, and will be useful for the general public, mineral collector, geology student, and professional geologist. If I were teaching Georgia geology, I would readily adopt this as my text. I already own two copies: one that is pristine for my library and one that is in the car with my field gear.

 

The Lost World of Fossil Lake: Snapshots from Deep Time by Lance Grande. University of Chicago Press, Chicago, IL 60637; www.press.uchicago.edu. 425 pages; 2013; $45 plus shipping and handling (hardbound).

At last, it's out! Green River Formation fossil enthusiasts have been awaiting this volume that was promised by Lance Grande, an internationally known paleoichthyologist at the Chicago Field Museum and overall doyen of all preserved life from Fossil Basin. Congratulations to Grande and all concerned; it does not disappoint. Quite the contrary, it eloquently conveys useful and interesting information and contains high-quality photographs printed on durable stock. With 425 pages, 243 color plates, several historical black-and-white reproductions, line drawings, and tables, and contained in an 8 × 10-inch format, this is a wonderful book.

Not just for Green River Formation fossil collectors, it is a comprehensive and beautifully illustrated study of a fossil community that has been collected extensively for 150 years. The Green River Formation fossil bonanza was first noticed during the 1840s by early explorers and missionaries, and its importance was further appreciated during completion of the Union Pacific Railroad in the 1860s. A famous railroad cut near the modern town of Green Rifle, Wyoming, was even called the “Petrified Fish Cut.” Ferdinand Hayden named these strata the Green River Shales in 1869. By the late 1800s, commercial and research quarries existed in the area now called Fossil Ridge or occupied by Fossil Butte National Monument.

In 1981 Grande published his dissertation titled Paleontology of the Green River Formation with a Review of the Fish Fauna. The Green River Formation is found in Wyoming, Utah, and Colorado, but as indicated in the thesis title, fossil fish were the main focus. The Wyoming Geological Survey reprinted the thesis as Bulletin 63, and it has been a best seller for the survey ever since, serving as the proverbial bible for Green River Formation collectors. Everyone in the fossil business knows of Lance Grande, and now we have the new and improved book on Fossil Basin from the high priest.

A more comprehensive and updated volume devoted to showcasing this fossil bounty was long overdue, but we are pleased that the most knowledgeable professional finally synthesized the paleontology, stratigraphy, and history of this deposit in one reference. Everyone can now appreciate the diversity of life that lived in, around, and above Fossil Lake, a lush semitropical environment that existed some 50 million years ago in what is now high and dry southwestern Wyoming.

Deposition in Fossil Lake lasted only 1–2 million years, quite brief compared to the 15 million or more years that other lakes containing Green River Formation sediments existed. But fossils featured in the new deep-time book are almost entirely from the Fossil Butte Member (FBM) of the Green River Formation that was deposited in only 10,000 years or less. This is an incredibly short period, geologically speaking. The FBM contains both the famous “18-inch layer” and underlying “sandwich layers.” The former averages about 18 inches in thickness and yields a high proportion of large and well-articulated fish; the latter produces enormous quantities of small split fish seen so commonly in hobby stores. The aquatic diversity found in this member exceeds the other thirteen members of the Green River Formation combined. This is because the FBM represents the largest, deepest, and freshest stage of Fossil Lake, and life forms were plentiful.

Many topics are covered in Grande's treatment. What were the ancestors of these fish, and what was the paleoenvironment in Fossil Lake for their deposition, especially the mass mortality layers? Methods of collection and preparation are discussed and illustrated, and an outline is given of a day in the life of a fossil fish digger.

Each section discussing a large group of animals begins with a useful diagram showing taxonomic hierarchy, often starting with a subphylum or order and branching down to family or genus/species, if known, and the associated common name, if it exists. Grande reports many interesting facts and statistics about the FBM fauna and flora. The volume contains the most comprehensive photographic record in existence—65 pages—for identified FBM plants. Also covered are the animal groups including arthropods, which consist of crayfish, shrimp, insects, and spiders; all known fish; amphibians including salamanders and frogs; reptiles including turtles, crocodiles, various lizards, and snakes; birds, which are preserved in greater diversity in the FBM than even fish; and mammals including various small animals, an early horse, and bats.

Grande has always been the source for proper fish names for the Green River Formation fossil collecting community. Now, in a simple but monumental stroke, he formally recognizes the original name of everyone's favorite little fancy fish, Priscacara liops, as Cockerellites liops! About 3 million labels will need to be revised in collections around the world. It is somewhat analogous to correcting the name of everyone's favorite giant herbivore dinosaur, Brontosaurus, to a previously described and identical animal, Apatosaurus, several decades ago. (There are still holdouts for Brontosaurus.)

A gracious and appreciative nod is given to major commercial quarriers, past and present. Even though their primary intent is profit driven, their extensive quarrying and splitting of important sequences are credited with the discovery of most of the remarkable fossils produced from the FBM, for unless you are extremely lucky, a lot of digging is necessary to find one rare or exceptional specimen.

A few glitches were noticed, such as Grande referring to the newly advised Cockerellities liops by the old name, Priscacara liops, on pages 207 and 212. And one of the three fish labeled Knightia eocaena on page 206 is really a Diplomystus encaustus—but, what the heck, the second printing will take care of these.

The price is exceptionally reasonable considering the number of color images and overall quality. At $45 or even less at other clearinghouses, you can buy several, which is what I did. What better gift for a young, impressionable paleontologist, say about eight years old, who knows only of dinosaurs. Here is a great introduction to other world-class fossil specimens representing an entire community of animals. Maybe a budding paleontologist will want to convince his parents that Wyoming is a great vacation destination and that fossil collecting or even science can be an inspiring lifetime pursuit. Buy it; it's a great volume!

 

The Fundamentals of Mining for Gemstones and Mineral Specimens by Jim Clanin. New England Historical Publications; order from www.jcmining.com. 403 pages; 2013; $49.95 plus shipping and handling (hardbound).

As the title suggests, this is a practically oriented book pointed toward the nuts and bolts of specimen and gemstone mining. It is well organized and takes advantage of materials distributed by various manufacturers of critical machinery and supplies as well as author Jim Clanin's varied experiences mining for those things most of us only see at major gem and mineral shows. The book has been enhanced by the editorial critique of several chapters by Dr. David London and Paul Henze and by Vandall King photographs. As a source book for understanding and solving mining problems related to what are essentially small mineral-deposits, keeping one ever mindful of safety issues, and benefiting from a person's experience who has already been there and done that, the book certainly meets its objectives.

The book begins with a short preface and introduction to gem mining that set the stage for Chapter 1, “Geology and Mineralogy.” This chapter is a brief review of specific geologic conditions and mineral species that are the object of gemstone and specimen prospecting and mining. Although short and certainly not comprehensive, it contains interesting maps and informative locality photographs. Chapter 2, an instructive and well-done chapter, is devoted to models, sketches, pictures, and maps. It deals not only with where to buy such things, but also with the fundamental types of illustrations required to understand the geometry of mineral deposits, the equipment needed to collect data, and how to present it in an understandable and usable way. Chapter 3 is devoted to mining equipment, not the huge loaders and 200-ton trucks so familiar in larger mines, but the drastically scaled-down versions of such equipment, beginning with the simple wheelbarrow. The chapter is full of good, practical information.

Explosives and blasting are covered in Chapter 4, which is yet another important and thorough treatment of critical mining practices and techniques. Chapter 5, “Practical Mining,” is a veritable treatise on small-scale mining. It is thoroughly illustrated with photographs and diagrams, leaving nothing to the imagination. How to dig pockets, specimen preparation, and marketing are the subjects in Chapter 6, a relatively short chapter considering the breadth of subject matter. The various aspects of mineral dressing, or mineral processing, is covered next, dealing heavily with screening techniques and water issues. Chapter 8 is a fascinating chapter covering the essentials of camp construction, sanitation issues, and green power. An entire chapter devoted to first aid appears next, replete with far too many illustrations of cuts, broken bones, and even severed limbs. Still, the information is important and designed to save lives in remote places.

How should one conduct one's self in a developing country? The answers are contained in Chapter 10 and include tips for purchasing gems and minerals. One might think that there could not possibly be anything left to discuss, but there is, and it is to be found in Chapter 11. Included in this chapter, titled “General Useful Knowledge,” are various important aspects of blacksmithing because, alas, there are no hardware stores around the corner in remote mining locations. The final chapter is devoted to every miner's favorite topics—the Mine Safety and Health Administration (MSHA) and the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF), the issuer of blasting permits in the United States. Important regulations are referenced, and the chapter should be read carefully by anyone contemplating mining in this country.

These twelve chapters present an exhaustive amount of information; however, one soon realizes, surprisingly, that there is still about half the book left. Most of the remainder consists of eight case studies in gem and specimen mining. These include emerald mining in Madagascar; the Landaban garnet mine in northern Tanzania; alluvial gem mining in southern Tanzania; gem and specimen mining in the Northern Areas of Pakistan; gem (ruby) and specimen mining in the Hunza Valley of the Northern Areas, Pakistan; the John Saul ruby and Hard Rock mines of southeastern Kenya; the well-known Cryo-Genie pegmatite, California; and fluorite mining in northern England. Each case study is well illustrated and thoroughly covers historical and mining aspects of the deposits with specific references to unique problems and situations.

The book closes with three appendices and an index. Appendix 1 is a rather comprehensive list of important terms and definitions. Appendix 2 presents references and other resources. Appendix 3 is a useful compilation of mining supply and other useful equipment companies.

Having a mining engineering background, I can certainly appreciate the breadth and importance of the information contained in this book. There are no frills. There are the occasional editorial glitches, but they are quite forgivable. The work is crammed with hundreds of photographs and many diagrams and drawings, each chosen to illustrate some critical aspect of the text. The book is fascinating and a must for anyone considering any type of commercial gem or specimen mining.

 

Rhodochrosite: Crystals of Drama and Nuance by William S. Logan. Spectrum Minerals, 1360 Betsy Dr., Charlotte, NC 28211; www.spectrumminerals.com. 159 pages; 2013; $78 (hardbound), $55 (softbound); $10 (ebook).

There are a number of unusual and interesting aspects of Rhodochrosite: Crystals of Drama and Nuance. The book itself was produced using Blurb, Inc.'s creative publishing services that make it possible for an author to essentially manage and produce a credible, well-illustrated book using little more than a computer. The result is good and from the standpoint of presentation, format, and composition, certainly worthy of any collector's bookcase. The obvious objective of the book is to clearly present to the mineral collector a relatively comprehensive treatise on the occurrence of specimen rhodochrosite, and to that end William S. Logan has been successful. He is an expert on rhodochrosite and writes from forty years' experience in amassing a rhodochrosite collection totaling more than one thousand specimens.

The book begins with a good introductory chapter that is split into two fundamental parts: a discussion of manganese and manganese carbonates, and an overview of the geology of manganese occurrences. Chapter 2 is a thoughtful discussion of rhodochrosite's chemical and physical properties, with individual sections covering color, hardness and cleavage, optical properties, crystallography and twins, crystal habits, aggregates, pseudomorphs, and cryptocrystalline varieties. Careful attention is given to color variations and the possible explanation for them. Chapter 3 is a useful discussion of the principles of specimen selection. Individual sections include those related to specimen size, aesthetics, provenance, and mineral associations. The meat of the book is contained in Chapter 4, simply titled “Localities.” These are presented geographically based essentially on representation in Logan's collection. The coverage begins with North America, followed by Mexico, South America, Europe, Africa, Australia, and Asia, in turn. The level of detail discussed for each location is based on the author's careful judgment of the credibility of labeling. If there is little doubt as to the specimen's origin, then significant and sometimes lengthy information is given, depending at times rather heavily on data contained in the mindat.org website. Of course, this material is augmented by information supplied by well-known dealers and collectors as well as the published literature. Colorado localities are deservedly treated in detail. Others for which specimens are difficult to acquire are given good coverage and include such localities as the now-closed Foote mine in North Carolina. Clearly not all rhodochrosite world localities can be included in this format, but a surprisingly large number are. Several eastern localities are missing such as North Carolina's other unusual rhodochrosite locality, the Tungsten Queen mine in the Hamme district, and Georgia's several historical specimen producers. Such omissions are likely not oversights but simply a reflection of the lack of specimen availability. Chapters 5 and 6 are short and to the point, covering specimen preparation, and display and lighting, respectively. Chapter 7 briefly discusses rhodochrosite as an investment. The book closes with acknowledgments, a bibliography, and a short index.

The book gains importance when one considers its 376 color photographs, essentially all of rhodochrosite specimens in Logan's collection. Most were taken by him, and he interestingly tells us that he uses a Nikon D3100 camera with 18-55mm and Nikkor 85mm macrolenses, and fluorescent lighting incorporated in the HP Marketing TopTablePro studio system with optional diffusion and back-lighting as needed. Most photographs are relatively small and suffer somewhat as a result, but the usefulness of such comprehensive photographic documentation makes this forgivable.

Rhodochrosite: Crystals of Drama and Nuance is a good book that likely could not have been written by any other author. It treats one of the most collectible of all minerals in an exhaustive way pointed directly at the mineral collector. It was edited by a selection of mineral dealers and a mineral photographer, and technically edited by well-known collector Tom Wilson. I am happy to have a copy and am sure that you will be also.

 

An Introduction to the Rock-Forming Minerals, 3rd ed., by William A. Deer, Robert A. Howie, and Jack Zussman. The Mineralogical Society, London. 498 pages; 2013; £45 plus shipping (softbound).

It is difficult to overstate the impact of the Rock-Forming Minerals Series on three generations of geologists and mineralogists. The original set of five volumes was published in 1962; the greatly expanded second edition now comprises about ten volumes and forms a small reference library in itself for scientists interested in these minerals, and particularly in the systematic mineralogy of the common silicates. In parallel to these massive compendia, a one-volume Introduction to the Rock-Forming Minerals was first published in 1966 and a second edition in 1992. This third edition expands and updates the treatment in a number of ways.

The book is organized into five sections: Ortho-, Di- and Ring Silicates; Chain Silicates; Layered Silicates; Framework Silicates; and Non-silicates. Within each section, short chapters are devoted to particular minerals or mineral groups. Each chapter begins with a highlighted box of property data and a brief synopsis of the geological environment in which the mineral typically occurs, along with distinguishing optical characteristics. Substantive discussions of structure, chemistry, distinguishing features, and paragenesis conclude with a “core collection” of suggested papers for further reading. Several useful appendices deal with calculating a formula from chemical analysis, calculating molecular percentage end-members, and optical properties as they pertain to petrographic microscopy.

Compared to the second edition, there are a number of notable improvements. The most obvious is the liberal use of color. More than ninety crystal structure diagrams are presented in full color, and the selection of models (ball and stick, polyhedral, or space filling) and viewing directions is very effectively used to best illustrate the important aspects of each structure. The power and versatility of CrystalMaker® software for visualizing complicated structures is further harnessed by the inclusion of a CrystalViewer™ interactive CD that contains a library of many of these structures (more on this later). Color also enhances some of the more complicated phase diagrams, and there are sixty-plus color photos of petrographic thin sections.

Each chapter has a table of selected analyses (identified by occurrence), which is extremely useful for showing the natural range of compositions and typical substitutions in a mineral or series. Many of these have been updated with more recent—and presumably more reliable—analyses. The treatment of the zeolites has been greatly expanded, and the feldspar chapters have been extensively revised. Lastly, more references are included in the individual entries. To keep the overall size about the same, some minerals have been dropped: humite, mullite, larnite, merwinite, spurrite, eudialyte, rankinite, tilleyite, axinite, most of the pyroxenoids, sapphirine, aenigmatite, astrophyllite, apophyllite, rhodochrosite, ankerite, huntite, and witherite. The format has been enlarged from 6 × 9 inches and 700 pages to 8.5 × 11.5 and 500 pages, which definitely makes for easier reading.

I selected several chapters for careful reading and found them to be well-written and substantially error-free. Chapters on tourmaline and zeolites are very good and consistent with current taxonomic thinking. The amphibole chapter recognizes that reclassification was ongoing at the time of publishing but does refer the reader to the paper defining the new nomenclature. As in earlier editions, some groups or series (e.g., staurolite) are treated as a single mineral with a wide range of compositions. Although some academic “splitters” and fanatical species collectors might find this unsatisfying, it makes perfect sense for the working geologist and keeps the size of the book manageable. In any case, it gives a solid background in the crystal chemistry to help the reader make sense of exhaustive species listings that are easily found elsewhere.

Several chapters (clay minerals, feldspathoids, serpentines, silica minerals, sulfides, and zeolites) include a one-page highlighted overview box, which is a nice capsule summary. Some are placed near the beginning of the chapter (e.g., serpentines), whereas others are inexplicably placed at the end (e.g., feldspathoids and zeolites).

The interactive CD installs CrystalViewer™ 8.3, which allows you to view .cmdf files that were created in CrystalMaker®; it does not allow you to edit them, other than to rotate the structure to view it from different angles. My only complaints are that the library of structure diagrams provided on the CD were mostly prepared with a black background, and the same cation is not always done in the same color from one mineral to the next. Despite these quibbles, it is an excellent visualization and teaching tool. Furthermore, those who have CrystalMaker® installed on another computer can transfer all of the .cmdf files they have created to their liking and open them with CrystalViewer™.

It is important to note that, at least for the time being, readers who wish to avoid shipping costs and currency translations can buy the book on Amazon, but the CD won't be included. Amazon is producing the book by print-on-demand, and I am told that they are adding a sentence to the online retailer product description saying the CD can be obtained at no charge by contacting the Mineralogical Society in London. I have copies of both versions of the book, and there is no perceptible difference in quality. For those in the United States who wish to avoid excess postage, the book is also available through the Mineralogical Society of America (MSA) at $80 plus shipping (MSA members get a 25 percent discount).

The book is intended primarily as a text for advanced undergraduate and graduate students in the earth sciences, as well as for scientists and engineers in other fields who want a one-volume reference to the minerals covered. It will serve these audiences superbly, but because the depth and richness of the treatment far exceed that of the typical mineral encyclopedia, I also recommend it to advanced mineral collectors who wish to expand their knowledge.

In this Issue

Taylor & Francis Group

© 2017 Taylor & Francis Group · 530 Walnut Street, Suite 850, Philadelphia, PA · 19106