The enigma of rare Quaternary oolites in the Indian and Pacific Oceans: A result of global oceanographic physicochemical conditions or a sampling bias?
Journal
Quaternary Science Reviews
Journal Volume
200
Pages
114-122
Date Issued
2018
Author(s)
Gallagher S.J
Reuning L
Himmler T
Henderiks J
De Vleeschouwer D
Rastigar Lari A
Fulthorpe C.S
Bogus K
Renema W
McGregor H.V
Kominz M.A
Auer G
Baranwal S
Castañeda S
Christensen B.A
Franco D.R
Gurnis M
Haller C
He Y
Ishiwa T
Iwatani H
Jatiningrum R.S
Korpanty C.A
Lee E.Y
Levin E
Mamo B.L
McHugh C.M
Petrick B.F
Potts D.C
Takayanagi H
Zhang W
Expedition 356 Shipboard Scientists
Abstract
Marine ooids are iconic indicators of shallow seawater carbonate saturation state, and their formation has traditionally been ascribed to physicochemical processes. The Indo-Pacific stands out as a region devoid of oolites, particularly during the Quaternary: the “ooid enigma”. Here we present results from recent coring by the International Ocean Discovery Program (IODP Expedition 356) off west Australia that shows that ooid horizons are common in Pleistocene strata up to 730,000 years old. Extensive “ooid factories” were created due to the presence of long-lived tidally influenced flat–topped tropical platforms suitable for intermittent ooid accretion over hundreds to thousands of years during highstands and times of lower sea level. This work suggests marine ooids may actually be more common in Indo-Pacific than previously reported. Past global ocean alkalinity was elevated during Pleistocene glacial periods and continental climate was generally more arid in the Indo-Pacific region compared to interglacials and the Holocene. Therefore, increased aridity associated with higher alkalinity conditions during the glacials facilitated ooid precipitation on adjacent tropical carbonate platforms particularly offshore from arid Australia. This confluence of factors suggests that more “ooid factories” may be encountered by further coring Indo-Pacific regions with Pleistocene flat long-lived carbonate shelves. However, Indo-Pacific Quaternary ooid occurrences outside Australia are rare, suggesting that the Northwest Shelf may be a unique archive of this non-skeletal precipitate. Further investigations into the petrography and geochemistry of pre-Holocene ooid occurrences will provide insights into their origin and the relative role of biotic, physicochemical and other factors in their formation. © 2018 Elsevier Ltd
Subjects
Aridity; Holocene; Indian Ocean; Indo-Pacific; Northwest Shelf Australia; Ooids; Ooids; Oolites; Oolites; Pacific Ocean; Quaternary; Quaternary; Skeletal grains; Southern Pacific
Other Subjects
Offshore oil well production; Petrography; pH; Sea level; Tropics; Aridity; Australia; Holocenes; Indian ocean; Indo-Pacific; Ooids; Oolites; Pacific ocean; Quaternary; Southern Pacific; Carbonation; accretion; alkalinity; aridity; bioindicator; carbonate platform; geochemistry; global change; Holocene; interglacial; Ocean Drilling Program; oceanography; oolite; paleoclimate; petrography; physicochemical property; Pleistocene; Quaternary; rare species; sampling bias; seawater; skeletal remains; Indian Ocean; Northwest Australian Shelf; Pacific Ocean
Type
journal article