TY - JOUR

T1 - New model for seasonal ikaite precipitation: Evidence from White Sea glendonites

AU - Vasileva, Kseniia

AU - Zaretskaya, Nataliya

AU - Ershova, Victoria

AU - Rogov, Mikhail

AU - Stockli, Lisa

AU - Stockli, Daniel

AU - Khaitov, Vadim

AU - Maximov, Fedor

AU - Chernyshova, Irina

AU - Soloshenko, Natalia

AU - Frishman, Nikolay

AU - Panikorovsky, Taras

AU - Vereshchagin, Oleg

N1 - Publisher Copyright: © 2022

PY - 2022/7

Y1 - 2022/7

N2 - The mineral ikaite (CaCO3·6H2O) and its pseudomorphs (glendonite) are considered as important paleoclimate indicators in the geological record. Here we examine the youngest known glendonites, their host concretions, and bivalve shells fossilized within these host concretions from the White Sea, north-western Russia. We applied mineralogical, geochemical and isotopic methods to shed new light on the paleogeographic and geochemical environments during ikaite precipitation and ikaite-calcite transformation. We show that White Sea glendonites are so far the youngest known glendonites in the world (4.1 ± 0.4 cal thousand years before present). Ikaite precipitation occurred during the cold winter months, accompanied by the formation of extensive sea ice and presence of decaying organic matter, which resulted in a small negative Ce anomaly and negative δ13C values. Increasing temperature led to ikaite dehydration and subsequent cementation with aragonite or amorphous calcium carbonate, containing elevated concentrations of Ba and Sr. Needle-like cements within glendonites display small negative Ce anomalies and precipitated from pore waters derived from seawater. The high‑magnesium calcite forming the host concretion precipitated in the sulfate-reduction zone from pore waters derived from seawater. The geochemistry of these pore waters was modified by interaction with clastic components of the host sediments, resulting in δ18O values comparable to those of dissolved inorganic carbon (DIC) and almost flat Post Archean Australian Shale (PAAS)-normalized rare earth element patterns. Therefore, we show that glendonites can be used as a proxy for near-freezing bottom water temperatures at least seasonally during the cold winter months. Changes in the geochemical composition of carbonate phases within the glendonites and host concretions can be used to determine successive changes in the geochemical environment during their formation.

AB - The mineral ikaite (CaCO3·6H2O) and its pseudomorphs (glendonite) are considered as important paleoclimate indicators in the geological record. Here we examine the youngest known glendonites, their host concretions, and bivalve shells fossilized within these host concretions from the White Sea, north-western Russia. We applied mineralogical, geochemical and isotopic methods to shed new light on the paleogeographic and geochemical environments during ikaite precipitation and ikaite-calcite transformation. We show that White Sea glendonites are so far the youngest known glendonites in the world (4.1 ± 0.4 cal thousand years before present). Ikaite precipitation occurred during the cold winter months, accompanied by the formation of extensive sea ice and presence of decaying organic matter, which resulted in a small negative Ce anomaly and negative δ13C values. Increasing temperature led to ikaite dehydration and subsequent cementation with aragonite or amorphous calcium carbonate, containing elevated concentrations of Ba and Sr. Needle-like cements within glendonites display small negative Ce anomalies and precipitated from pore waters derived from seawater. The high‑magnesium calcite forming the host concretion precipitated in the sulfate-reduction zone from pore waters derived from seawater. The geochemistry of these pore waters was modified by interaction with clastic components of the host sediments, resulting in δ18O values comparable to those of dissolved inorganic carbon (DIC) and almost flat Post Archean Australian Shale (PAAS)-normalized rare earth element patterns. Therefore, we show that glendonites can be used as a proxy for near-freezing bottom water temperatures at least seasonally during the cold winter months. Changes in the geochemical composition of carbonate phases within the glendonites and host concretions can be used to determine successive changes in the geochemical environment during their formation.

KW - Ikaite

KW - Glendonite

KW - Calcite generations

KW - CLIMATE

KW - Diagenesis

KW - White Sea

KW - Climate

UR - https://www.sciencedirect.com/science/article/pii/S0025322722000913#!

UR - http://www.scopus.com/inward/record.url?scp=85130520101&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/19941794-2554-3ed8-86f6-953e283a3ea6/

U2 - 10.1016/j.margeo.2022.106820

DO - 10.1016/j.margeo.2022.106820

M3 - Article

VL - 449

JO - Marine Geology

JF - Marine Geology

SN - 0025-3227

M1 - 106820

ER -