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Things you need to do before you try nearest neighbour analysis in pipe rock facies

on . Posted in General Ichnology

piperock

One of the remarkable things about the predominantly Lower Palaeozoic pipe-rock facies is the sheer intensity of bioturbation by the vertical tubular trace fossil Skolithos.

The question that has been asked by a number of earlier authors is... How does the palaeoecology represented in pipe-rock compare to modern marine systems?

Over the last few years my Ph.D. student Michael Garton and I have been working at methods to study the fabrics produced in ancient sediments by the action of burrowing organisms (ichnofabrics).  The quartz-rich sandstones of the pipe-rock facies are particularly difficult to study.

 

Our work with large thin transparent slices of pipe-rock has yielded a wealth of fabric information that has not been available to earlier workers.

Perhaps because of the difficulties in studying pipe-rock, some generalizations and gross over-simplifications have been applied to field data which have been used to interpret the palaeoecology of the pipe rock and the palaeobiology of the trace maker.

In this paper we show examples of pipe-rock ichnofabrics as revealed by our large thin slicing technique, and demonstrate some of the pitfalls in using nearest neighbour analysis to interpret bedding plane assemblages of Skolithos pipe rock without doing due diligence by way of ichnofabric analysis.

 

McIlroy, D. & Garton, M. 2010. Realistic interpretation of ichnofabric and palaeoecology of the pipe rock biotope. Lethaia in press

http://www3.interscience.wiley.com/journal/122682980/abstract