Dr. Andrew D. Miall (University of Toronto, Canada)
Dr. Andrew D. Miall has been Professor of Geology in the Department of Earth Sciences at the University of Toronto since 1979, where he has developed an extensive career in teaching and research in the stratigraphy and sedimentology of sedimentary basins. His work has focused particularly on sequence stratigraphy, the sedimentology of nonmarine sandstones and their characterization as reservoir rocks for non-renewable resources, and the analysis of the preservation of time in the stratigraphic record and its implications for interpreting geologic history.
Throughout his academic career, he has published numerous books and numerous scientific articles in specialized international journals, establishing himself as a global reference in basin analysis and stratigraphy.
He was the inaugural holder of the Gordon Stollery Chair in Basin Analysis and Petroleum Geology, established in 2001 at the University of Toronto. In recognition of his scientific contributions, he was elected Fellow of the Royal Society of Canada in 1995.
Abstract
Joseph Barrell (1917) was one of the first to realize that stratigraphic accumulation is fragmentary, with preservation occurring only when space is available (due to subsidence or sea-level rise), and deposits avoid erosion. Wheeler (1958, 1959) developed the concept of what we now term “Wheeler diagrams” in which stratigraphic cross-sections are drawn with time as the y-axis. These serve to highlight the incomplete nature of the stratigraphic record. Derek Ager (1973) argued that accumulation is very fragmentary, the record consisting of “more gaps than record”. Sadler (1981) demonstrated that sedimentation rates are inversely proportional to the elapsed time represented by the measured section, a log-log relationship that holds over fourteen orders of magnitude in time scale and nine orders of magnitude in sedimentation rate. The result of all this work has been the realization that the stratigraphic record consists of what Bailey and Smith (2010) termed “frozen accidents,” amalgamated across sedimentary breaks that represent missing time intervals ranging from seconds to hundreds of millions of years. The increasing availability of precise methods of dating, by biostratigraphy, radio-isotopic methods, etc., and the increasing power of facies analysis and sequence stratigraphy to unravel depositional settings, is enabling us to relate rates and time scales to specific geological processes, leading to a holistic view of stratigraphy as the product of multiple processes acting simultaneously over all geological time scales. “Stratigraphic completeness” may then be understood as a composite value, comprising nested sedimentary units formed at time scales ranging over fourteen orders of magnitude, separated by breaks representing a similar wide range of time scales A focus on the integrated time-hierarchy of processes, from the turbulence of bedload transport to the progress of thermal subsidence in a sedimentary basin, strengthens the interpretation of the preserved product, from the cross-bed set to the basin fill.
