On
Tuesday 12 November, as well our regular
WEGA session, there is a
Western Regional Group (WRG) lecture. This coincidence continues with the respective speakers, Profs Brian Williams and Ted Nield, who are friends and also went to the same grammar school in Swansea!
WRG lecture: Ted Nield: Incoming! Or, Why We Should Stop Worrying and Learn to Love the Meteorite
Meteorites have been the stuff of legend throughout human history, and since 1980 the idea that dinosaurs were wiped out by a meteorite strike 65 million years ago has become one of the most widely known scientific ideas of all. However, the causes of the end Cretaceous mass extinction were complex, and the idea that major meteorite strikes are always bound to be bad news for life on Earth is being challenged by fresh discoveries. New research is suggesting that 470 million years ago, a stupendous collision in the Asteroid Belt (whose débris is still falling, to this very day) bombarded the Earth with meteorites of all sizes. A revolutionary idea is emerging that the resulting ecological disturbance may have been responsible not only for massive worldwide submarine landslides, but for the single greatest increase in biological diversity since the origin of complex life the hitherto unexplained Great Ordovician Biodiversity Event.
Ted Nield will be known to people from his role as editor of the Geological Society’s monthly magazine Geoscientist, and for his books Supercontinent and his most recent book, Incoming!
WRG has extended an invitation to WEGA members to attend this lecture.
This talk will be in the Reynolds Lecture theatre (G25) and starts at 18:30
WEGA lecture: Brian Williams : From Bergs to Ergs: the Permo-Carboniferous glaciation of gondwana and its hydrocarbon potential
The supercontinent of Gondwana during Permo-Carboniferous times covered a vast area of some 120 million km2. It mainly comprised the land masses of Africa, Arabia, Australia, Antarctica, South America, India, Madagascar and Sri Lanka. Individual, largely intracratonic basins are of huge dimensions; over 600,000 km2 in South America (Parana Basin) and 450,000 km2 in Australia (Canning Basin). Glaciations shaped the landscape of the supercontinent particularly in the Late Carboniferous and Early Permian when it lay between 35o and 75o S. Petroleum prospectivity within this domain is still in an early phase although in excess of 100 fields have been discovered and are appraised at some 20 billion bbl of oil in place, mainly in Arabia, and 7-10 TCF of gas, largely in Australia. Hydrocarbon occurrences are most common within intracratonic basins with some restricted to foreland and rift basins. Source rocks tend to comprise older or younger mudrock sequences; trap styles are variable, and seal and reservoir rocks occur within the glaciogenic realm.
Glaciogenic facies comprise deposition in a bewildering kaleidoscope of environments and subenvironments assigned to supraglacial, subglacial, terminoglacial and proglacial settings although seal and reservoir facies are normally restricted to the latter two depositional realms. Basin infill-architecture is complex due to rapid changed in facies, both spatially and temporally, and the influence of periodic ice sheet advance and retreat producing multiple phases of erosion.
Current research, centred on Oman and West and South Australia, is addressing these key issues relating to the global evolution of the Permo-Carboniferous ice sheet, climatic versus tectonic control on sedimentation, characterisation of reservoir units and integration of outcrop with subsurface data.
The WEGA lecture will be in G8, and will start at 20:00. The regular WEGA wine and cheese event will be held at 19:30 following the WRG lecture
