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Cluster analysis of published foraminifera and palynologic data from the recent Gulf Coast and Orinoco Delta, and company data from subsurface Mackenzie Delta and Canadian East Coast offshore, was undertaken in an effort to establish meaningful interpretation of subsurface biostratigraphic data. These data were integrated with sediment, hydrographic, well cuttings, core and well log data, in order to effect an integrated sedimentologic-biostratigraphic understanding of the results.
Interpretation of the above cluster analyses indicates the level of resolution applicable to subsurface data, and provide reasons for much of the difficulty of interpretation. Problems related to sampling density, and sample contamination are more readily recognized and can often be overcome. Abundance trends and species interrelationships which cannot be recognized otherwise, become quite meaningful when correlated with sediment or lithology. R-mode can be mapped indirectly. The results indicate such analysis is applicable to any part of the geologic record containing adequate paleontologic information. The data utilized can be expanded to include as many parameters as desired.
This study emphasizes the need to redefine philosophy and objectives in exploration biostratigraphy. Interpretation of core, logs and lithology is necessary to permit facies considerations. Advance planning to long-term projects having broad general applicability, but which are compatible concurrently with short-term exploration needs, must become standard procedure. Expansion of interpretation capability beyond the usual “tops” or “age” approach will improve credibility with other exploration disciplines. Breakdown of resistance to utilization of statistical approaches is necessary before their value can be fully appreciated. The technique works and provides very useful results. However, it requires learning experience, the willingness to maintain an open mind, and the recognition that it may not be justified for some studies.
Acknowledgments and Associated Footnotes
1 Trend Exploration Limited
2 Shell Canada Resources Ltd., Calgary, Alberta
Copyright © 2009 by the Canadian Society of Petroleum Geologists