In this section
@article{Prince:2024:10.1016/j.sedgeo.2024.106711,
author = {Prince, K and Laya, JC and Budd, D and Manche, CJ and Jacquemyn, C},
doi = {10.1016/j.sedgeo.2024.106711},
journal = {Sedimentary Geology},
title = {Dolomite occurrence within drift deposits, Maldives archipelago},
url = {http://dx.doi.org/10.1016/j.sedgeo.2024.106711},
volume = {470},
year = {2024}
}
TY - JOUR
AB - Considerable attention has been dedicated to the sedimentological processes associated with carbonate drift and contourite deposits, but a noticeable gap exists in the understanding of the diagenetic aspects of those deposits, especially dolomitization. This study presents an examination of dolomites from Middle to Late Miocene drift deposits collected during IODP Expedition 359 to the Maldives archipelago. Multiple geochemical parameters and petrographic analysis are used to explore the potential role of closed versus open system dolomitization in the two oldest drift sequences, which are overlain by a multimillion year-long hiatus. Overall, dolomite abundance is variable, but 50 % to nearly 100 % in a 30 m thick interval below the unconformity surface at one of the examined sites. The dolomite in the study interval consists of very fine-to-fine-sized crystalline dolomite cements and mimetically replaced dolomite grains. All dolomite is non-stoichiometric (mean 42.7 ± 2.0 mol% MgCO3) and mostly poorly ordered. Geochemical attributes include relatively invariant δ13C (+1.3 ‰ to +1.7 ‰ VPDB) and relatively high Sr concentrations in dolomite cements (mean 505 ppm) and dolomitized grains (mean 784 ppm). δ18O values and the constraints of burial histories indicate dolomitization in normal marine seawater at burial depths of 0 to 300 m and temperatures of ∼10 °C–14 °C below an ocean water column 100 to 400 m deep. Sr-isotope ages suggest dolomitization of the most extensively dolomitized interval below the unconformity occurred between 12.3 Ma and 6.7 Ma. Overall, the geochemical data and previously published δ34SCAS data suggest a closed, diffusion-dominated system created most of the dolomite. However, the youngest dolomite's age and bulk rock Sr isotope ages of calcitic rocks at the base of the drift deposits can only be explained by the advective flux of seawater through all the drift deposits. Furthermore, the
AU - Prince,K
AU - Laya,JC
AU - Budd,D
AU - Manche,CJ
AU - Jacquemyn,C
DO - 10.1016/j.sedgeo.2024.106711
PY - 2024///
SN - 0037-0738
TI - Dolomite occurrence within drift deposits, Maldives archipelago
T2 - Sedimentary Geology
UR - http://dx.doi.org/10.1016/j.sedgeo.2024.106711
VL - 470
ER -