A History of Ideas in Ichnology - Trace Fossils as Indicators of Sedimentary Environments - page 2

1. INTRODUCTION

Among one and another rock layer, there are the traces of the worms that crawled in
them when they were not yet dry.
Leonardo da Vinci, Leicester Codex, folio 10 v

Since the beginnings of ichnology, trace fossils have been recognized for their
twofold nature as biological and sedimentological objects. As a discipline
studying biogenic sedimentary structures, ichnology proved to be very impor-
tant for paleontology and sedimentary geology as well.
The tendency of applying trace fossils in the characterization of past depo-
sitional environments manifested itself very early. Leonardo da Vinci used
trace fossils to prove the marine origin of the sedimentary successions of the
Apennines ( Baucon, 2010 ), but it took ichnology four centuries to develop
comprehensive and precise scientific tools for the needs of paleoenvironmental
analysis. Nowadays, ichnology is a matter of great interest due to the huge spec-
trum of potential applications such as facies interpretation, paleoenvironmental
reconstruction and recognition of discontinuities, prospecting and exploration
of hydrocarbon resources.
This chapter aims to delineate the progression from empirical knowledge
toward the modern concepts of ichnology, with particular regard to the appli-
cation of ichnology to facies analysis. This has guided our areas of emphasis
so that, for example, we give invertebrate traces a greater allocation of space
than vertebrate traces because they find more sedimentological applications.
The purpose of this chapter is to provide information not only about ichnol-
ogists and their theories but also why they developed an idea as they did. For this
reason, particular attention has been given to the specific social and historical
circumstances surrounding the individual line of thought. Similarly, we fol-
lowed a global perspective, based on the belief in the international character
of ichnology.
Tracing the global history of ichnology is possible through the texts which
have survived, hence the necessity of compiling a comprehensive bibliographic
database on the history of ichnology (see the Supplementary Material: http://
booksite.elsevier.com/9780444538130 ). The purpose is to show semiquantita-
tively the chronological relationships among various branches of ichnology
based upon similarities and differences in the interpretation of traces.

2. THE AGES OF ICHNOLOGY
Although the study of trace fossils is an important field for the solution of fun-
damental and applied problems of geology, there is a lack of general historical
overviews. With the exception of studies on specific episodes and geographical
areas, the only general historical accounts are those of Osgood (1970, 1975 ;
invertebrate ichnology) and Sarjeant (1987 ; vertebrate ichnology).