The Holocene Pulleniatina Minimum Event revisited: Geochemical and faunal evidence from the Okinawa Trough and upper reaches of the Kuroshio current
Resource
Marine Micropaleontology 59: 153-170
Journal
Marine Micropaleontology
Journal Volume
59
Journal Issue
3-4
Pages
153-170
Date Issued
2006
Author(s)
Lin, Yu-Shih
Lin, In-Tian
Yu, Pai-Sen
Chiang, Hong-Wei
Chen, Chen-Yin
Mii, Horng-Sheng
Abstract
The Holocene Pulleniatina Minimum Event (PME) is characterized by a very low abundance of the planktonic foraminifer Pulleniatina obliquiloculata between ∼ 4.5 and 3 ka. The PME occurs widely in the Okinawa Trough and the South China Sea, and can be correlated throughout this area; it has been related to variability in the Kuroshio current. To further explore the nature of the PME, we studied cores obtained from the southern Okinawa Trough and the upper reaches of the Kuroshio current. Faunal census data indicate that all cores record the PME between ∼ 4.5 and ∼ 3 ka. The relative abundance of Neogloboquadrina dutertrei is negatively correlated to that of P. obliquiloculata in the southern Okinawa Trough, but not in the sites at the upper reaches. Mg/Ca and δ18O measurements on Globigerinoides ruber shells from the southern Okinawa Trough indicate that there was no change in sea surface temperature or sea surface salinity during the PME. The vertical structure of the water column as reconstructed by multispecies δ18O and δ13C profiles shows no consistent anomalies in the southern Okinawa Trough and western Philippine Sea during the PME. These observations suggest that: (1) the PME was not restricted to marginal seas, but widespread in the western North Pacific. (2) The high abundance of N. dutertrei during the PME in the Okinawa Trough may be a result of higher food-availability in the absence of P. obliquiloculata. (3) No distinctive, consistent anomalies in the paleoceanographic proxies are associated with the PME, implying there were no changes in hydrography and productivity. The absence of a linkage between faunal variation and paleoceanographic proxies indicates that we do not yet understand what causes changes in planktonic foraminiferal assemblages. This lack of understanding implies that we cannot always trust fauna-based paleothermometry at millennial timescales. © 2006 Elsevier B.V. All rights reserved.
Subjects
Holocene; Kuroshio; Mg/Ca ratio; Pulleniatina minimum event; thermocline hydrography; Western North Pacific
SDGs
Other Subjects
fauna; Holocene; marine environment; paleontology; plankton; salinity; sea surface temperature; East China Sea; Okinawa Trough; Pacific Ocean; Pacific Ocean (North); Philippine Sea; South China Sea; Foraminifera; Globigerinoides ruber; Neogloboquadrina dutertrei; Pulleniatina; Pulleniatina obliquiloculata
Type
journal article