Pyrolysis Study of Organic Matter from Deep Sea Drilling Project Sites 370 (Leg 41), 415, and 416 (Leg 50)

Abstract

We analyzed 180 samples of Pleistocene to Tithonian sediments, using the pyrolysis technique. The results show a preponderance of detrital continental organic matter. Most samples contain altered organic matter and are in an immature stage of evolution. A detailed examination of the pyrolysis and depth data shows a correlation between lithology and depositional environment.

Site 547

“…The organic matter seems to be of a residual terrestrial nature, similar to that in most of the Cenozoic sediments at the other sites drilled during Leg 79. This general characteristic is in accordance with microscopic and organic geochemical evidence for organic matter in hemipelagic Tertiary sediments in other areas of the Northwest African continental margin, for example, at DSDP Sites 397 and 415 (Rullkötter et al, 1982), although Boutefeu (1980) reports higher hydrogen index values. The hydrocarbon potential of the organic matter in these sediments is nil.…”

“…21); thus the organic matter is of terrigenous origin and partly oxidized during transport, which reduces the hydrocarbon potential to a negligible or at best low level, for gas generation only. A similar kerogen type was encountered in the late Cenomanian and Albian sediments at DSDP Site 415 in the Agadir Canyon off Morocco (Boutefeu, 1980). 3.…”

“…The lower boundary of this sequence is defined by an unconformity which, from extrapolation of DSDP Sites 415 and 416 (Lancelot and Winterer, 1980), corresponds with reflector Red (Horizon R in Figs. 30 and 31).…”

Transport of terrestrial organic matter in the Ogooué deep sea turbidite system (Gabon)

“…These TOC contents are equally high compared to most of fossil analogs (e.g. Boutefeu and Labofina, 1980;Shipboard Scientific Party, 1990;Meyers et al, 1996;Watanabe and Akiyama, 1998;Caja and Permanyer, 2008;Deniau et al, 2010). Among the different studies published in the literature, the Kutei Basin (Indonesia) represents the best fossil analog of the modern Ogooué turbidite system.…”

Sites 552–553

“…The second S 2 peak has only been observed in one sample from Unit IV. Boutefeu (1976) has observed a shoulder on the S 2 peak. However, in this case two distinct types of kerogen may be observed because of the very low levels present.…”