Has Chemostratigraphy Evolved into a Mainstream Stratigraphic Technique?

Tim J. Pearce¹, Ken T. Ratcliffe², and John H. Martin^2
1 Chemostrat Ltd, Llanymynech, United Kingdom
² Chemostrat Ltd,

This paper demonstrates how chemostratigraphy has evolved from a “last resort” technique into a mainstream stratigraphic tool. It has long been recognised that inorganic elemental data can be used to characterise stratigraphic variations, and gamma ray (K, Th and U) data (one form of chemostratigraphy) is an industry standard. However, over the last 15 years, with the advent of refined XRF and ICP instrumentation, this basic approach has been enhanced with routine studies being based on up to 50 elements. Consequently, chemostratigraphy now represents an important tool in the oil industry by providing correlation of continental deposits, and high-resolution sub-biostratigraphic correlation in both marine clastic and carbonate sequences.

This paper presents a series of case studies from barren Carboniferous continental sequences from the Southern North Sea, turbidites from the Northern North Sea and carbonates from the Middle East that illustrate how the technique has evolved as a pragmatic and practical tool for the correlation of core and cuttings sections, both in the laboratory and at wellsite. The examples also address issues such as sample quality, sample preparation, diagenetic overprint and the influence of facies that often lead to misconceptions and scepticism about the technique. In addition to correlation, this paper will discuss other applications of the geochemical dataset such as aiding in the modelling of sediment provenance, predicting the sedimentological facies and the controls on porosity and permeability.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005