CHAPTER 19 • Palaeoenvironmental Reconstructions
-10
-15
+ /
CO2
Yeast
-20
8 13 e
-25
•
+ 1\
-30
Lactate
-35
425
-40
Tropical land plants
Common land plants
Lacustrine higher plants
Fresh water plankton
Marine vertebrates
Marine invertebrates
Marine higher plants
Marine plankton (+22 °C)
Marine plankton (+ 1 0c)
Marine sulphate reducing bacteria
Marine chemautotrophic bacteria
Fig. 19.1. Ranges of stable carbon isotope values for total OC in living organisms. Redrawn from Degens
(1969)
Stable carbon isotopes are frequently used to estimate contributions from marine
and terrigenous sources of organic matter in marine sediments. Early work
(e.g. Hedges and Parker 1976; Gearing et al. 1977) showed a trend in 013e of bulk
OC as one progresses from continental shelf (ol3e -26%0) to off-shore sediments
(013e -19 to -21%0) in the Gulf of Mexico. Most terrigenous OC would be deposited
on the inner shelves, and little is transported to outer shelves and continental slopes,
indicating a minimal contribution of land-derived OC to surface sediments of the Gulf.
Other studies (e.g. Prahl and Muelhausen 1989; Gofii et al.1998) have suggested that a
-10
-15
+ /
CO2
Yeast
-20
8 13 e
-25
•
+ 1\
-30
Lactate
-35
425
-40
Tropical land plants
Common land plants
Lacustrine higher plants
Fresh water plankton
Marine vertebrates
Marine invertebrates
Marine higher plants
Marine plankton (+22 °C)
Marine plankton (+ 1 0c)
Marine sulphate reducing bacteria
Marine chemautotrophic bacteria
Fig. 19.1. Ranges of stable carbon isotope values for total OC in living organisms. Redrawn from Degens
(1969)
Stable carbon isotopes are frequently used to estimate contributions from marine
and terrigenous sources of organic matter in marine sediments. Early work
(e.g. Hedges and Parker 1976; Gearing et al. 1977) showed a trend in 013e of bulk
OC as one progresses from continental shelf (ol3e -26%0) to off-shore sediments
(013e -19 to -21%0) in the Gulf of Mexico. Most terrigenous OC would be deposited
on the inner shelves, and little is transported to outer shelves and continental slopes,
indicating a minimal contribution of land-derived OC to surface sediments of the Gulf.
Other studies (e.g. Prahl and Muelhausen 1989; Gofii et al.1998) have suggested that a