Taphonomy: A Process Approach
This book offers a comprehensive review of the entire field of taphonomy, the science of fossil preservation. It describes the formation of plant and animal fossils in oceanic, terrestrial and river settings and how this affects deciphering the ecology and extinction of past lifeforms and the environments in which they lived. Coverage emphasizes a process approach to the subject and reviews the taphonomic behavior of all important taxa, both plant and animal. The book will be of main interest to advanced students and professionals working in paleontology, stratigraphy, sedimentology, climate modeling and biogeochemistry. It will also appeal to anyone interested in the preservation of fossils and the formation of fossil assemblages.
Fossilization, information -- and scientific illustration, August 2, 2000
I should explain first of all that I am a professional geologist specializing in physical sedimentology (though my doctorate, long years ago was in stratigraphic paleontology). My initial reaction to seeing this book was strongly positive: "At last", I thought, "an inexpensive book that will bring us up to date on this interesting field, on the borders between palaeontology and sedimentology." And such a book is badly needed because most sedimentologists are not as knowledgeable about paleontology (and the fashionable modern subdisciplines of paleoecology and taphonomy) as they should be. As I started to read this book, however, my enthusiasm diminished. Who are the target readers? The author explains in the preface that taphonomy "is concerned with the information content of the fossil record and the processes by which fossils are incorporated into the fossil record." (Would it not have been better to write "by which organic remains and traces are incorporated..."?). But he never really tells us who he sees as his readers. The style, however, soon establishes that this is NOT a book for the common reader, nor even for students. It is written in the style of a series of extended professional review papers -- heavy on the completeness of the documentation, incorporating much jargon, only partly explained, and many cryptic summaries of papers, that are short on explaining what the authors really did. A fuller discussion of fewer examples would have made this a better book. One of the author's professed messages is that fossilization does not simply result in LOSS of information (about the original organisms), but also in gain of information about sedimentary and organic processes, averaged over time scales that are otherwise difficult to observe because they are longer than a human lifetime. After initial chapters on biostratinomy (the relationship between an organism and its environment after death and during burial -- so dealing with decay, physical effects of transport by water, and early diagenetic (chemical) modification of shell or bone structure), he continues to bioturbation and other time-averaging processes, examples of exceptional preservation (such as the Burgess Shale fauna), and chapters on large scale phenomena, such as sea-level change and changes in chemical and organic processes through Phanerozoic time. A penultimate chapter deals with the relevance of taphonomy to modern environmental concerns such as climate change and organism extinctions. All these are important topics, and I am very glad to have an up-to-date source of references on them, but (based on the topics that I know something about) I am wary of the author's capsule comments on the (very broad range of) subjects that he discusses. I close with an example of a neglected field for taphonomic studies: the fate of illustrations as they become fossilized in the scientific literature. The author's Figure 2.4 (on p. 32) caught my eye, for the simple reason that I happened to draw both parts of the diagram myself. There is no reference, however, to the original source of the diagrams. Instead they are credited to a textbook by Sam Boggs. Boggs gives full source information, and a long figure caption that gives a nearly but not-quite accurate description of what the diagram depict: Part A (from a set of notes, published by SEPM in two editions, and designed by John Southard and myself to acquaint geologists who lacked a strong physical/mathematical background with the essential fluid mechanics they needed to understand sediment transport) shows the various forces acting on a grain lying on the bed of an alluvial stream; Part B shows a more idealized picture of the flow and forces acting on a cylinder lying in an inviscid flow over a plane bed. This part was actually first published in an article by Briggs and myself, published in 1965, but was reprinted (without acknowledgement, since I was the original artist) in a text, published in 1972, and cited by Boggs. Boggs, however, states that it shows flow "over a grain," and fails to mention that the "grain" is a cylinder, and the flow is inviscid. The reason for using this greatly simplified version of reality is that there is a theoretical solution available (dating back to Jeffreys, 1929), so the streamlines and pressures shown are calculated, not just imagined. Boggs reproduces the figures without modification, but in Martin's book they have been redrafted, with the unfortunate result that the pressure force vectors are no longer to scale, and in fact are almost all of equal length. This, if true, would lead to the erroneous conclusion that such a "grain" suffers NO lift force -- which is the exact opposite of what the diagram was designed to demonstrate! Indeed, in this case fossilization of these figures and their explanation, originally published in the 1960s, has lead to a serious loss of information. Martin's text shows other evidence of his shaky grasp of fluid mechanics: on p.28 he writes that "shear-stress at the sediment water interface...is called shear velocity," (whereas shear velocity is the square root of the boundary shear stress divided by the fluid density). In explaining the Shield diagram on p.32, he remarks that u* is the "friction velocity (a measure of turbulence)" -- without pointing out that the friction velocity is just a different name for the shear velocity, and that it does not directly measure turbulence, but is roughly equal to the root mean square of the VERTICAL COMPONENT of turbulent velocities, close to the bed. Though it is surprising that Martin cites as his authority on the mechanics of sediment transport only an elementary textbook by an author best known for his work in sedimentary petrology (omitting references to accessible books by J.R.L. Allen, and M.J. Leeder, for example) it is even more surprising that he omits any reference to the works of Steven Vogel, notably his "Life in Moving Fluids: The Physical Biology of Flows" (Princeton, 2nd ed., 1994). Judging from a quick scan of some of the major symposia that he cites, this gap between the disciplines of taphomy, and physical sedimentology and physical biology, seems to be found in other leading taphonomists too. Hopefully it will not persist.
very interesting book, January 27, 2007
perfect to those who want to know more on paleontology .i am happy i didnt listen to mr g.v middleton( above )as he give extremely partial perspective
to this book.the only LOSS of information is that Ronald E. Martin forget mention his name ...- not for the lazy reader!
Rating: not rated | Added on: 21 Dec 2007
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