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Biography Research is centred on the origins and characteristics of carbonate sediments and rocks. Following a study of Devonian limestones I worked in the Seychelles as part of the International Indian Ocean Expedition (financed by NERC). Focused initially on the origins and distribution of carbonate sediments in reef environments, the project came to incorporate experimental studies of carbonate sediment dynamics, and the physical biological origins of sedimentary structures in carbonate environments.
Comparative investigations of reefs in Florida and the Bahamas, and subsequently the Red Sea (Sudan), shifted the emphasis towards facies geometry and the architecture of reefs and larger scale carbonate systems. The ideas developed were first tested on Pleistocene limestones when I joined the Royal Society’s Aldabra (Western Indian Ocean) Expedition. My remit in this was to determine the geological history of the island and to relate this to the pattern of colonization of the important endemic fauna. The relative youth of the sequence simplified comparison with present environments, and provided analogues for much older rocks. Work on Aldabra, and later in Kenya and Mauritius, underlined the importance of sea-level history, and thus of climatic change, to the development of carbonate systems over the last million years but also in the more distant past.
Climate and environmental change have become the focus of research with colleagues in France, Germany and Italy, centred again on the Western Indian Ocean. Financed by the EU this has involved collaboration with workers in 9 laboratories across Europe. Corals and reef systems provide highly sensitive indices of environmental conditions through the medium of stable and radiogenic isotope analyses. Sclerochronology and high-resolution isotope geochemistry, have been used, with petrography and aminostratigraphy, to examine regional and global climatic changes reflected in sea-surface temperatures over the last 350 years. Deeper boreholes in the Seychelles, Reunion, Madagascar and Mayotte have formed the basis for investigation of the pattern of sea-level rise over the last 10,000 years and, incorporating earlier work, a comparison between present conditions and those of the last interglacial. Global warming can only be properly assessed in the light of data concerning past climatic cycles.
An NERC grant formed the basis of collaboration with a consortium centred in Australia and including French, Swiss, Spanish and Japanese co-workers, investigating boreholes through the Great Barrier Reef in Australia. The aim has been partly environmental, concerned with sea-level change and thus with changing climate. In addition, however, allied to results of the Ocean Drilling Programme, interpretations are centred on the manner in which these factors have controlled accumulation on the margin of the world's largest contemporary carbonate platform over the last 700,000 yrs.
In parallel with these key themes, the period on Aldabra combined a study of palaeosols and other evidence of subaerial emergence within the succession. This included the discovery of vertebrate remains that provided important evidence of successive island colonizations. At that time petrographic work on rocks of this kind was relatively novel and it led to investigations of palaeosols in Kenya and of freshwater carbonate deposits, including cave and stream deposits and sediments in carbonate lakes. In the last I continued studies, begun on Aldabra, of microbially mediated precipitation of carbonates in stromatolites. Working with colleagues in the Natural History Museum in London these have incorporated issues of organic mediation of mineral growth and skeletogenesis.
During an early visit to the Seychelles I was able to investigate insular phosphorite deposits in the Amirantes. Phosphorites, commonly associated with carbonates, are one of the world's strategic minerals but are also important for their implications for the interpretation of climate and ocean upwelling (palaeooceanography). At that time little was known of the petrography of such deposits. I subsequently also described cave-related phosphorites on Aldabra and was a contributor to IGCP 156.
Petrography has provided the foundation to many of these studies and a significant proportion of publications relate to the diagenetic history of carbonate rocks, tracking the movement of the formative fluids, and the timing of fluid flow in relation to burial, issues of particular importance in relation to dolomites and relevant to both the oil and minerals industries.
Research interests My research has centred on the sedimentology and petrography of carbonate rocks and has included investigations of marine and a variety of subaerial systems including cave and lake deposits and calcrete. Current research Current projects include work with French colleagues on boreholes in Mururoa, French Polynesia, and the Great Barrier reef of Australia. These are investigating the petrographic signature of sea-level changes on the sedimentary record. The work is financed by an Emeritus Feolowship from the Leverhulme Trust. Recent publications | View all publications >> Braithwaite,CJR and Montaggioni, LF in press The Great Barrier Reef: a 700,000 year Diagenetic History. Sedimentology
Braithwaite, CJR., Robinson, RJ. and Jones,G. 2006, Sabellarids: A hidden danger, or an aid to subsea pipelines? Quarterly Journal of Engineering Geology and Hydrogeology, v. 39: 259-265.
Janoušek, V., Gerdes, A., Vrána, S., Finger, F., Erban, V. Friedl, G. and Braithwaite, CJR. 2006, Low-pressure Granulites of the Lišov Massif, Southern Bohemia: Viséan Metamorphism of Late Devonian Plutonic Arc Rocks. Journal of Petrology ,v.47: 705-744. Braithwaite, CJR, 2005. Carbonate Sediments and Rocks: a manual for Earth Scientists and Engineers. Whittles Publishing. 164 pp. Braithwaite, CJR. 2005, Sedimentology, Chap 3, pp 57-84 In: Geomorphology for Engineers, Fookes, P. G., Lee, E. M. and Milligan, G. (eds).Whittles Publishing, 851 pp. Teaching responsibilities Honours courses, Petroleum Geology, Engineering Geology. |
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