Abstract

This paper elaborates the second of three themes treated in my 1978 SEAPEX contribution. The aim is to demonstrate that a common kind of so-called practical lithostratigraphy often results in untenably generalized concepts concerning the formation and succession of palaeogeographic scenarios, and therewith in dubious exploration strategies. The problem seems to be particularly rife in young sedimentary basins filled with very thick but monotonously repetitive sequences of coastal plain and delta facies.

The first case discussed is the Bengal Basin where it is postulated that lithostratigraphic units such as the Surma Group cover a time interval from the Oligocene into the Quaternary - some 20-25 million years - while remaining petrographically unchanged through space and time. This paper claims that this is not possible.

A similar and worse case is the Gippsland Basin in southeastern Victoria. There one has managed to create an even more astonishing lithostratigraphic monster, known as the Latrobe Group, which spans the whole time interval from the mid-Cretaceous to the late Miocene, around 90 M.Y. This is 10 M.Y. longer than the entire Cambrian, almost twice the Permian, and more than trice the Silurian!

What kind of stratigraphy is that? Should one call that progress? If so, why?