Reconstruction of past climate variability and ENSO-like fluctuations in the southern Gulf of California (Alfonso Basin) since the last glacial maximum

2015/04/16 by Francisca Staines-Urías, Oscar González-Yajimovich, O. González-Yajimovich +1
Earth and Planetary Sciences · Environmental Science · #Geology and Paleoclimatology Research #Methane Hydrates and Related Phenomena #Geological formations and processes

paper · doi:10.1016/j.yqres.2015.03.007

Abstract

Nannofossil assemblages from core MD02-2510 provide a ~ 22 ka record of past oceanographic variability in Alfonso Basin (Gulf of California, east subtropical Pacific). In this area, environmental conditions depend on a monsoonal system heavily influenced by changes in the location of the ITCZ and nearby atmospheric pressure centers. To reconstruct nutricline depth and ENSO-like variability, two ecological indexes were calculated based on the relative abundance of the three dominant coccolith species. The late glacial period is characterized by intensified wind-driven upwelling, high primary productivity and La Niña-like conditions. An environmental shift occurs during the glacial–interglacial transition, El Niño-like conditions intensify, nutricline deepens and surface productivity declines. The late Holocene is characterized by a persistent increase in nutricline depth and dominance of El Niño-like conditions. The fluctuations in the composition of the coccolith assemblages can be related to orbital-scale fluctuations in the average position of the ITCZ. However, while the ENSO-like signal that overprints the record varies in response to orbital forcing, on suborbital time scales the relation between ENSO-like conditions and the average position of the ITCZ and the North Pacific High changes, suggesting that the development of persistent El Niño-like conditions is strongly dependent on the specific climatic background.

Citations

• Hydrological changes and paleoproductivity in the Gulf of California during middle and late Holocene and their relationship with ITCZ and North American Monsoon variability
• The preserved carbonate record in Holocene sediments of the Alfonso and Pescadero basins, Gulf of California, Mexico
• Climate and ocean variability during the middle and late Holocene recorded in laminated sediments from Alfonso Basin, Gulf of California, Mexico

Related

• Climate and ocean variability during the middle and late Holocene recorded in laminated sediments from Alfonso Basin, Gulf of California, Mexico
• Hydrological changes and paleoproductivity in the Gulf of California during middle and late Holocene and their relationship with ITCZ and North American Monsoon variability
• Climate variability and silicoflagellate fluxes in Alfonso Basin (southern Gulf of California)
• Late Quaternary climate change record from two long sediment cores from Guaymas Basin, Gulf of California
• Sea‐surface temperature records of Termination 1 in the Gulf of California: Challenges for seasonal and interannual analogues of tropical Pacific climate change