TY - JOUR
T1 - Mid‐Holocene rainfall seasonality and ENSO dynamics over the south‐western Pacific
AU - Nava‐Fernandez, Cinthya
AU - Braun, Tobias
AU - Pederson, Chelsea L.
AU - Fox, Bethany
AU - Hartland, Adam
AU - Kwiecien, Ola
AU - Höpker, Sebastian N.
AU - Bernasconi, Stefano
AU - Jaggi, Madalina
AU - Hellstrom, John
AU - Gázquez, Fernando
AU - French, Amanda
AU - Marwan, Norbert
AU - Immenhauser, Adrian
AU - Breitenbach, Sebastian F. M.
N1 - Funding information: This research has been supported by the European Union's Horizon 2020 Research and Innovation programme through a Marie Skłodowska-Curie grant (no. 691037) and aligned funding from Te Apārangi Royal Society of New Zealand (grant no. RIS-UOW1501) and the Rutherford Discovery Fellowship programme (grant no. RDF-UOW1601). Cinthya Nava-Fernandez acknowledges financial support from the German Academic Exchange Service (DAAD). F.G. acknowledges the Ramón y Cajal fellowship, RYC2020-029811-I and the grant PPIT-UAL, Junta de Andalucía-FEDER 2022–2026 (RyC-PPI2021-01).
PY - 2024/2
Y1 - 2024/2
N2 - El Niño–Southern Oscillation dynamics affect global weather patterns, with regionally diverse hydrological responses posing critical societal challenges. The lack of seasonally resolved hydrological proxy reconstructions beyond the observational era limits our understanding of boundary conditions that drive and/or adjust El Niño–Southern Oscillation variability. Detailed reconstructions of past El Niño–Southern Oscillation dynamics can help modelling efforts, highlight impacts on disparate ecosystems and link to extreme events that affect populations from the tropics to high latitudes. Here, mid‐Holocene El Niño–Southern Oscillation and hydrological changes are reconstructed in the south‐west Pacific using a stalagmite from Niue Island, which represents the period 6.4–5.4 ka BP. Stable oxygen and carbon isotope ratios, trace elements and greyscale data from a U/Th‐dated and layer counted stalagmite profile are combined to infer changes in local hydrology at sub‐annual to multi‐decadal timescales. Principal component analysis reveals seasonal‐scale hydrological changes expressed as variations in stalagmite growth patterns and geochemical characteristics. Higher levels of host rock‐derived elements (Sr/Ca and U/Ca) and higher δ18O and δ13C values are observed in dark, dense calcite laminae deposited during the dry season, whereas during the wet season, higher concentrations of soil‐derived elements (Zn/Ca and Mn/Ca) and lower δ18O and δ13C values are recorded in pale, porous calcite laminae. The multi‐proxy record from Niue shows seasonal cycles associated with hydrological changes controlled by the positioning and strength of the South Pacific Convergence Zone. Wavelet analysis of the greyscale record reveals that El Niño–Southern Oscillation was continuously active during the mid‐Holocene, with two weaker intervals at 6–5.9 and 5.6–5.5 ka BP. El Niño–Southern Oscillation especially affects dry season rainfall dynamics, with increased cyclone activity that reduces hydrological seasonality during El Niño years.
AB - El Niño–Southern Oscillation dynamics affect global weather patterns, with regionally diverse hydrological responses posing critical societal challenges. The lack of seasonally resolved hydrological proxy reconstructions beyond the observational era limits our understanding of boundary conditions that drive and/or adjust El Niño–Southern Oscillation variability. Detailed reconstructions of past El Niño–Southern Oscillation dynamics can help modelling efforts, highlight impacts on disparate ecosystems and link to extreme events that affect populations from the tropics to high latitudes. Here, mid‐Holocene El Niño–Southern Oscillation and hydrological changes are reconstructed in the south‐west Pacific using a stalagmite from Niue Island, which represents the period 6.4–5.4 ka BP. Stable oxygen and carbon isotope ratios, trace elements and greyscale data from a U/Th‐dated and layer counted stalagmite profile are combined to infer changes in local hydrology at sub‐annual to multi‐decadal timescales. Principal component analysis reveals seasonal‐scale hydrological changes expressed as variations in stalagmite growth patterns and geochemical characteristics. Higher levels of host rock‐derived elements (Sr/Ca and U/Ca) and higher δ18O and δ13C values are observed in dark, dense calcite laminae deposited during the dry season, whereas during the wet season, higher concentrations of soil‐derived elements (Zn/Ca and Mn/Ca) and lower δ18O and δ13C values are recorded in pale, porous calcite laminae. The multi‐proxy record from Niue shows seasonal cycles associated with hydrological changes controlled by the positioning and strength of the South Pacific Convergence Zone. Wavelet analysis of the greyscale record reveals that El Niño–Southern Oscillation was continuously active during the mid‐Holocene, with two weaker intervals at 6–5.9 and 5.6–5.5 ka BP. El Niño–Southern Oscillation especially affects dry season rainfall dynamics, with increased cyclone activity that reduces hydrological seasonality during El Niño years.
KW - multi‐proxy reconstruction
KW - ENSO
KW - Niue Island
KW - mid‐Holocene
KW - speleothems
KW - mid-Holocene
KW - multi-proxy reconstruction
UR - http://www.scopus.com/inward/record.url?scp=85184170660&partnerID=8YFLogxK
U2 - 10.1002/dep2.268
DO - 10.1002/dep2.268
M3 - Article
SN - 2055-4877
VL - 10
SP - 176
EP - 194
JO - The Depositional Record
JF - The Depositional Record
IS - 1
ER -