Palynology, acritarchs and getting beyond the biostratigraphic range chart in stratigraphy
|Starts:||17:00 18 Oct 2018|
|Ends:||18:00 18 Oct 2018|
|What is it:||Seminar|
|Organiser:||Department of Earth and Environmental Sciences|
|Who is it for:||University staff, Current University students|
|Speaker:||Dr Stewart Molyneux|
This week's AAGP speaker is Dr Stewart Molyneux from the British Geological Survey.
Palynology has contributed much to hydrocarbon exploration and production including,
among other things, biostratigraphic dating of sections, interpretation of environments
of deposition and assessment of thermal maturity. Biostratigraphic dating relies on the
determination of species’ ranges, the construction of range charts and the establishment
of biozones (based on various criteria), leading to the correlation of sections. But what
controls the extent of palynomorph ranges – the local originations and extinctions of species?
This talk focuses on this question using a group of marine Palaeozoic palynomorphs, the
acritarchs, to illustrate the development of ideas, using data from case studies in the
Middle East, the English Lake District and the Welsh Borderland. Turnover in the species
composition of acritarch assemblages can be linked to low order sea level changes. The
exact response in any one section depends on the position of the section along the
onshore-offshore gradient. So, for example, successive high diversity assemblages characterise
individual Cambrian–Silurian marine flooding events on the Arabian Plate, whereas high
diversity assemblages are associated with low stands in the Early Ordovician basinal succession
of the Lake District in NW England. At higher orders, however, the response can be more
subtle, and discerning it benefits from the application of multivariate techniques. The use
of such methods, more commonly used in community ecology, adds value to biostratigraphic
studies, producing insights which, when considered in conjunction with other data sets, can
enhance our understanding of stratigraphic sections.
Dr Stewart Molyneux
Role: Honorary Research Associate
Organisation: British Geological Survey
Biography: Stewart joined the British Geological Survey (BGS) after three years of research for his Ph.D., and stayed with the organisation for the rest of his career, latterly as head of the BGS team of palaeontologists. He also worked on BGS contracts with companies exploring Lower Palaeozoic targets in the Middle East (Oman, Saudi Arabia), North Africa (Algeria, Libya) and Eastern Europe (Poland, Romania). Stewart has served on the Councils of The Micropalaeontological Society and the Yorkshire Geological Society, and on the editorial boards of the Journal of the Geological Society,Palynology, and the Proceedings of the Yorkshire Geological Society(including a long stint as Principal Editor), and also edited a number of sheet memoirs and other publications for the BGS.
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