Coal Rank Series – Multiple Choice: 24-Pet-A1 Principles of Stratigraphy and Sedimentation, Undated paper, Q6

Question 6 of 19: Coal Rank Series – Multiple Choice

Nivaar worked solution (AI-drafted; not reviewed by a licensed engineer)

Notes on this paper

EGBC National Exam — Petroleum Engineering, 17-Pet-A1 Principles of Stratigraphy & Sedimentation, 2019-May. 3 hours duration; closed book, approved Sharp/Casio calculator permitted. The paper has two parts: Part A (Questions 1–10, Sedimentology and Sedimentary Processes) – Questions 1 and 2 are mandatory (10 marks each, 20 marks), plus any five of the remaining eight (3–10) at 6 marks each (30 marks), for a Part A total of 50 marks; and Part B (Questions 11–19, Stratigraphy and Sedimentary Basin Analysis) – answer any six of the nine at 6 marks each, for a Part B total of 36 marks – an 86-mark maximum (50 for Part A + 36 for Part B).

Check: the mark values and question count used throughout this solution (6 marks each for Questions 3–19, Part A = 50, Part B = 36, maximum = 86) are as printed on the paper.

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 (sandstone/carbonate classification, diagenesis, porosity); Nichols, G., Sedimentology and Stratigraphy, 2nd ed., Wiley-Blackwell (fluvial/deltaic/deep-marine systems, sequence stratigraphy, stratigraphic units); Reading, H.G. (ed.), Sedimentary Environments: Processes, Facies and Stratigraphy, 3rd ed., Blackwell (facies models, alluvial fans, deltas, deep-marine systems); Selley, R.C. & Sonnenberg, S., Elements of Petroleum Geology, 3rd ed., Academic Press (basin analysis, well-log correlation, seismic/acoustic impedance); International Commission on Stratigraphy, International Chronostratigraphic Chart (geological time scale).

Question 6: Coal Rank Series – Multiple Choice (6 marks)

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.

Answer: (C) Peat → lignite → subbituminous → bituminous → anthracite. Coalification is the progressive devolatilization of buried peat under increasing temperature and pressure: as burial depth/duration increases, moisture and volatile matter are steadily driven off while the proportion of fixed carbon rises. This produces a strictly ordered rank series – peat (unconsolidated, high-moisture plant debris) → lignite ("brown coal", still high moisture) → subbituminous (reduced moisture) → bituminous (the common industrial/coking rank) → anthracite (highest rank: lowest moisture and volatile matter, highest fixed carbon). Options A, B and D each reorder at least one rank out of sequence and are inconsistent with this monotonic, one-way maturation trend.