Molecular fossils as a tool for tracking Holocene sea-level change in the Loch of Stenness, Orkney

TY - JOUR

T1 - Molecular fossils as a tool for tracking Holocene sea-level change in the Loch of Stenness, Orkney

AU - Conti, Martina L.G.

AU - Bates, Martin R.

AU - Preece, Richard C.

AU - Penkman, Kirsty E.H.

AU - Keely, Brendan J.

N1 - © 2020 The Authors. Journal of Quaternary Science Published by John Wiley & Sons Ltd.

PY - 2020/10/1

Y1 - 2020/10/1

N2 - Sediments deposited in the Loch of Stenness (Orkney Islands, Scotland) during the Holocene transgression, previously dated to between ~5939–5612 bp, were analysed for molecular fossils – lipids and chlorophyll pigments from primary producers – that complement conventional microfossil and lithological approaches for studying past sea-level change. While microfossil and lithological studies identified a transgression between 102 and 81 cm core depth, key molecular fossils fluctuate in occurrence and concentration between 118 and 85 cm, suggesting an earlier start to the transgression. Terrestrial lipid concentrations decreased and algal-derived, short-chain, n-alkanoic acid concentrations increased at 118 cm, indicating a disruption of the freshwater lake conditions associated with the early stages of the marine transgression. The lipid and pigment analyses provided information that complements and extends that from microfossil analysis, presenting a more complete record of Holocene sea-level changes and local vegetation changes in the Loch of Stenness. The isostatic stability of Stenness during the Holocene points towards other factors to explain the transgression, such as regional factors and/or melting of the Antarctic ice sheet (which occurred up to 3 ka).

AB - Sediments deposited in the Loch of Stenness (Orkney Islands, Scotland) during the Holocene transgression, previously dated to between ~5939–5612 bp, were analysed for molecular fossils – lipids and chlorophyll pigments from primary producers – that complement conventional microfossil and lithological approaches for studying past sea-level change. While microfossil and lithological studies identified a transgression between 102 and 81 cm core depth, key molecular fossils fluctuate in occurrence and concentration between 118 and 85 cm, suggesting an earlier start to the transgression. Terrestrial lipid concentrations decreased and algal-derived, short-chain, n-alkanoic acid concentrations increased at 118 cm, indicating a disruption of the freshwater lake conditions associated with the early stages of the marine transgression. The lipid and pigment analyses provided information that complements and extends that from microfossil analysis, presenting a more complete record of Holocene sea-level changes and local vegetation changes in the Loch of Stenness. The isostatic stability of Stenness during the Holocene points towards other factors to explain the transgression, such as regional factors and/or melting of the Antarctic ice sheet (which occurred up to 3 ka).

KW - chlorophylls

KW - Holocene

KW - lipids

KW - molecular fossils

KW - sea level

UR - http://www.scopus.com/inward/record.url?scp=85090151663&partnerID=8YFLogxK

U2 - 10.1002/jqs.3238

DO - 10.1002/jqs.3238

M3 - Article

AN - SCOPUS:85090151663

VL - 35

SP - 881

EP - 891

JO - Journal of Quaternary Science

JF - Journal of Quaternary Science

SN - 0267-8179

IS - 7

ER -