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Practical pipe rock palaeoecology?

on . Posted in Published

words PipeRock

Shallow marine sandstone from the lower palaeozoic of both Laurentia and Gondwana are commonly dominated by the vertical tubular trace fossil Skolithos.

The trace fossil fabrics (ichnofabrics) produced by the Skolithos trace maker(s) are highly distinctive (colloquially termed pipe-rock ichnofabrics), and regionally important as the pipe-rock commonly forms tight gas reservoirs.

One of the remarkable things about pipe-rock ichnofabrics is the sheer density of burrows.

In recent years several authors have attempted to glean palaeoecological and palaeobiological information on the palaeoecology of Lower Palaeozoic shallow marine palaeoenvironments through nearest neighbour analysis of bedding plane exposures of Skolithos pipes, in Scotland, and in Newfoundland and Labrador in particular.

Michael Garton (a Ph.D. student under my supervision-now graduated) has developed a remarkably powerful technique for the study of ichnofabrics in low contrast facies such as shallow marine sandstones.  The technique involves cutting a large thin slice of rock and grinding it until it is translucent, at which stage details of the sediment fabric not visible in weathered or slabbed cross sections can be revealed.

Application of this technique to pipe rock facies from Scotland and Newfoundland causes us to treat with caution ichnological studies of pipe-rock from bedding planes, that does not incorporate careful ichnofabric analysis.

This paper demonstrates the effectiveness of our large thin slicing technique, and proposes protocols through which meaningful nearest neighbour analysis could potentially be undertaken.

See:

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

http://onlinelibrary.wiley.com/doi/10.1111/j.1502-3931.2009.00199.x/abstract