TY - JOUR
T1 - Tracking Holocene palaeostratification and productivity changes in the Western Irish Sea: A multi-proxy record
AU - Woods, Mark A.
AU - Wilkinson , Ian P.
AU - Leng, Melanie J.
AU - Riding, James B.
AU - Vane, Christopher H.
AU - Lopes dos Santos, Raquel A.
AU - Kender, Sev
AU - De Schepperd, Stijn
AU - Hennissen, Jan A. I.
AU - Ward, Sophie L.
AU - Gowing, Charles J. B.
AU - Wilby, Philip R.
AU - Nichols, Matthew D.
AU - Rochelle, Christopher A.
PY - 2019/10/15
Y1 - 2019/10/15
N2 - The Western Irish Sea preserves an exceptionally thick (ca. 40 m) Holocene succession that is ideally suited to
understanding the pattern of palaeostratification and water mass productivity changes in the region, and their
relationship with sea level, sedimentation, and biota. Additionally, the presence of shallow-buried methane provides an
opportunity to explore its potential impact on the local pattern of Holocene marine environmental change. Multi-proxy
investigation of a cored borehole succession through the Holocene interval tracks changes from mixed to seasonally
stratified conditions. In the earliest Holocene (11.2–10 ka), high productivity, mixed water conditions prevailed, with
abundant and diverse foraminifera and dominant heterotrophic dinoflagellate cysts. Productivity was probably driven
by high nutrient fluxes related to high rates of sedimentation (>1600 cm/kyr), in turn influenced by relatively low sea
level and restricted sediment accommodation space across shelf areas to the east of the borehole site (eastern Irish
Sea Basin). With rising sea level in the later part of the Early Holocene, the region evolved into a relatively lower
productivity mixed water mass system, with significant changes in ecology revealed by dinoflagellate cysts and
foraminifera. In the latest Early Holocene and earliest Mid Holocene (ca. 8.4–8.2 ka) a return to higher productivity is
signalled by dinoflagellate cyst data; a result of seasonal stratification becoming established, evidenced by sharply
increased summer sea surface temperature estimates (typically 16–17⁰C) that contrast with an opposite (more
positive) trend in δ18O values for benthic foraminifera. Reductions in turbulent mixing associated with stratification
might have exacerbated the palaeoecological impact of shallow-buried methane associated with the borehole site,
potentially evidenced by a significant change in dominant benthic foraminifera and strong, localised excursions in the
benthic δ13C/ δ18O record.
AB - The Western Irish Sea preserves an exceptionally thick (ca. 40 m) Holocene succession that is ideally suited to
understanding the pattern of palaeostratification and water mass productivity changes in the region, and their
relationship with sea level, sedimentation, and biota. Additionally, the presence of shallow-buried methane provides an
opportunity to explore its potential impact on the local pattern of Holocene marine environmental change. Multi-proxy
investigation of a cored borehole succession through the Holocene interval tracks changes from mixed to seasonally
stratified conditions. In the earliest Holocene (11.2–10 ka), high productivity, mixed water conditions prevailed, with
abundant and diverse foraminifera and dominant heterotrophic dinoflagellate cysts. Productivity was probably driven
by high nutrient fluxes related to high rates of sedimentation (>1600 cm/kyr), in turn influenced by relatively low sea
level and restricted sediment accommodation space across shelf areas to the east of the borehole site (eastern Irish
Sea Basin). With rising sea level in the later part of the Early Holocene, the region evolved into a relatively lower
productivity mixed water mass system, with significant changes in ecology revealed by dinoflagellate cysts and
foraminifera. In the latest Early Holocene and earliest Mid Holocene (ca. 8.4–8.2 ka) a return to higher productivity is
signalled by dinoflagellate cyst data; a result of seasonal stratification becoming established, evidenced by sharply
increased summer sea surface temperature estimates (typically 16–17⁰C) that contrast with an opposite (more
positive) trend in δ18O values for benthic foraminifera. Reductions in turbulent mixing associated with stratification
might have exacerbated the palaeoecological impact of shallow-buried methane associated with the borehole site,
potentially evidenced by a significant change in dominant benthic foraminifera and strong, localised excursions in the
benthic δ13C/ δ18O record.
KW - Methane
KW - Microfossils
KW - Palaeotidal modelling
KW - Rock-Eval
KW - Sea surface temperature
KW - Stable isotopes
U2 - 10.1016/j.palaeo.2019.06.004
DO - 10.1016/j.palaeo.2019.06.004
M3 - Article
SN - 0031-0182
VL - 532
JO - Palaeogeography, Palaeoclimatology, Palaeoecology
JF - Palaeogeography, Palaeoclimatology, Palaeoecology
ER -
