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Irwertebrate Ichnology of Continental Freshwater Environments

Luis Alberto Buatois and Mana Gabriela Mangano

SUMMARY: The study of Continental ichnofaunas has shown an explosive development during the last decade. At present, three Continental archetypal ichnofacies are accepted: the Scoyenia, Mermia, and Coprinisphaera ichnofacies. Integration of ichnologic, sedimentologic, and paleobiologie information is very useful in facies analysis and sequence stratigraphy of Continental successions.

INTRODUCTION

Continental invertebrate ichnology has experienced a remarkable development during the last fifteen years. Extensive research has resultecl in the construc-tion of an expanding dataset and the proposal of archetypal ichnofacies (e.g., Smith et al., 1993; Bromley, 19%; Buatois and Manganu, 19958, 2004; Cenise et al., 2000, 2004a,b; Genise, 2004). Alsu, the potential and iimitations of the ichnofabric approach to the study of Continental ichnofaunas have been addressed in a number of studies (Buatois and Mangano, 1998; Cienise et al., 2004a; Buatois et al., in press »). Additionally, various studies nttempt to eyafuate temporal and spatial trends in tracę fossil dwłóbutłon (Buatois and Manganu, I993a; Genise and Bown, l‘ma,h; Buatois et al., I998a; l .abandeirn, 2002; 2004).

In thm rhapter we will review mir present knowl-22 ^fl* ^Hwater ichnofaunas, essentinlly those ^inv,rrff'briitf>s l irst, we briefly evalunte Vf»al Continental it hnofac ies defined. / w# tfress the utillty of Mogenic structurps ł.H

facies analysis by providing a summary of the ichnology of fluvial and lacustrine environments. Third, we discuss the potential contributions of the ichnofabric approach to the study of Continental ichnofaunas. Fourth, we address the sequence strati-graphic significance of freshwater ichnofaunas. Fifth, we review examples of individual ichnotaxa in marinę vs. Continental realms. Sixth, we discuss the presence of freshwater ichnofaunas in environments that are not strictly Continental but marginal marinę. In this chapter we stress the importance of a combined approach to the study of Continental ichnofaunas in space and time, using sedimentologic, stratigraphic, paleoecologic and paleobiologie datasets. Analysis of terrestrial ichnofaunas in paleosols is beyond the scope of this chapter, but excellent revievvs have been recently published (Genise, 2004; Genise ot al., 2004a).

CONTINENTAL ICHNOFACIES

The ichnofacies concept was proposed by Soilachor (1967) and Bubsequemdy refined in a serios of papers (eg.. Frey and Seilacher, 1980; Frey and IVml>ortxm.

1984, 1985; Bromley, I990> l'996j IVmlx-r(on oł al.. this vulume; Bromley and Asgaard, 1993; Gibert et al., L99Ś; Buatois et al., 2002). Seila* herian or atvhetvp*l ichnofacies are tracę fossil assemblagos that nsaic thnmgh long tntervals Ol geologie time atut atv characterlstle of a glven set of envinmmontal ttwult tlóftś (l^;rev and IVmberton, 1984* I9H.M. A cnmpunent of the łchnotacies concept is their a»vhe łypał naturę I his impltes th*d |"vuliar lo* al

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