24-Pet-A1 Principles of Stratigraphy and Sedimentation · May 2016
Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)
EGBC National Exam — Petroleum Engineering, 98-Pet-A1 Principles of Stratigraphy & Sedimentation, 2016-May. 3 hours duration; closed book, no calculator permitted. The paper has two parts: Part 1 (Questions 1–12, Sedimentology and Sedimentary Processes – 10 marks each; answer any eight of the twelve, 80 marks total) and Part 2 (Questions 13–20, Stratigraphy and Sedimentary Basin Analysis – 10 marks each; answer any five of the eight, 50 marks total) – a 130-mark maximum (80 for Part 1 + 50 for Part 2).
Reference texts: Boggs, S. Jr., Principles of Sedimentology and Stratigraphy, 5th ed., Pearson (grain texture, sediment transport, bedforms, carbonate/evaporite systems, sequence stratigraphy, unconformities, stratigraphic principles); Tucker, M.E., Sedimentary Petrology, 3rd ed., Blackwell (carbonate classification, diagenesis, dolomitization); Nichols, G., Sedimentology and Stratigraphy, 2nd ed., Wiley-Blackwell (fluvial systems, sequence stratigraphy, stratigraphic units); Reading, H.G. (ed.), Sedimentary Environments: Processes, Facies and Stratigraphy, 3rd ed., Blackwell (facies models, trace fossils, coastal processes); Selley, R.C. & Sonnenberg, S., Elements of Petroleum Geology, 3rd ed., Academic Press (source rocks, basin classification, reservoir quality); International Commission on Stratigraphy, International Chronostratigraphic Chart (geological time scale).
Question text not reproduced: the examination questions are © Engineers and Geoscientists BC. Open the official past paper (linked at the top of this page) to read the question, then follow the worked solution below.
A biozone (biostratigraphic zone) is a body of rock strata defined and characterized by its fossil content, independent of lithostratigraphic or chronostratigraphic boundaries. Four principal categories are recognized (International Stratigraphic Guide / North American Stratigraphic Code):
| Category | Definition |
|---|---|
| Range zone | The total stratigraphic and geographic range of occurrence of a taxon (taxon-range zone), or the overlap interval between the ranges of two selected taxa (concurrent-range zone) |
| Interval zone | The stratigraphic interval between two specified biostratigraphic events (datums) – e.g., between the first occurrence of one taxon and the first (or last) occurrence of another – without reference to the full range of any single taxon |
| Assemblage zone | A body of strata characterized by a distinctive natural assemblage or association of three or more taxa, taken together, regardless of their individual total ranges |
| Abundance (acme) zone | A body of strata in which a particular taxon (or taxa) is significantly more abundant than in the strata above and below, defined by a peak in relative abundance rather than by presence/absence or range |
