TY - JOUR
T1 - Alkenones, alkenoates, and organic matter in coastal environments of NW Scotland
T2 - Assessment of potential application for sea level reconstruction
AU - Bendle, James
AU - Rosell-Melé, Antoni
AU - Cox, Nicholas J.
AU - Shennan, Ian
PY - 2009/12
Y1 - 2009/12
N2 - Reconstruction of late Quaternary sea level history in areas of glacioisostatic uplift often relies on sediment archives from coastal isolation basins, natural coastal rock depressions previously isolated from or connected to the sea at different times. Proxy indicators for marine, brackish, or lacustrine conditions combined with precise dating can constrain the time when the sea crossed the sill threshold and isolated (or connected) the basin. The utility of isolation basins in investigations of sea level change is well known, but investigations have been mostly limited to microfossil proxies, the application of which can be limited by preservation and nonanalog problems. Here we investigate the potential of long-chain alkenones, alkenoates, and bulk organic parameters (TOC, Corg/N) for reconstructing past sea level changes in isolation basins in NW Scotland. We analyze organic biomarkers and bulk parameters from both modern basins (at different stages of isolation from the sea) and fossil basins (with sea level histories reconstructed from established proxies). Logit regression analysis was employed to find which of the biomarker metrics or bulk organic measurements could reliably characterize the sediment samples in terms of a marine/brackish or isolated/lacustrine origin. The results suggested a good efficiency for the alkenone index %C37:4 at predicting the depositional origin of the sediments. This study suggests that alkenones could be used as a novel proxy for sea level change in fossil isolation basins especially when microfossil preservation is poor.
AB - Reconstruction of late Quaternary sea level history in areas of glacioisostatic uplift often relies on sediment archives from coastal isolation basins, natural coastal rock depressions previously isolated from or connected to the sea at different times. Proxy indicators for marine, brackish, or lacustrine conditions combined with precise dating can constrain the time when the sea crossed the sill threshold and isolated (or connected) the basin. The utility of isolation basins in investigations of sea level change is well known, but investigations have been mostly limited to microfossil proxies, the application of which can be limited by preservation and nonanalog problems. Here we investigate the potential of long-chain alkenones, alkenoates, and bulk organic parameters (TOC, Corg/N) for reconstructing past sea level changes in isolation basins in NW Scotland. We analyze organic biomarkers and bulk parameters from both modern basins (at different stages of isolation from the sea) and fossil basins (with sea level histories reconstructed from established proxies). Logit regression analysis was employed to find which of the biomarker metrics or bulk organic measurements could reliably characterize the sediment samples in terms of a marine/brackish or isolated/lacustrine origin. The results suggested a good efficiency for the alkenone index %C37:4 at predicting the depositional origin of the sediments. This study suggests that alkenones could be used as a novel proxy for sea level change in fossil isolation basins especially when microfossil preservation is poor.
KW - Alkenones
KW - Biomarker proxies
KW - C/N
KW - Organic geochemistry
KW - Sea level change
UR - http://www.scopus.com/inward/record.url?scp=76149138042&partnerID=8YFLogxK
U2 - 10.1029/2009GC002603
DO - 10.1029/2009GC002603
M3 - Article
AN - SCOPUS:76149138042
SN - 1525-2027
VL - 10
JO - Geochemistry Geophysics Geosystems
JF - Geochemistry Geophysics Geosystems
IS - 12
M1 - Q12003
ER -