UNIGE document Scientific Article
previous document  unige:94788  next document
add to browser collection

Dating the Paleoproterozoic snowball Earth glaciations using contemporaneous subglacial hydrothermal systems

Zakharov, D.O.
Bindeman, I.N.
Slabunov, A.I.
Coble, M.A.
Serebryakov, N.S.
Published in Geology. 2017, vol. 45, no. 7, p. 667-670
Abstract The presence of Paleoproterozoic glacial diamictites deposited at low latitudes on different continents indicates that three or four worldwide glaciations occurred between 2.45 and 2.22 Ga. During that time period, the first atmospheric oxygen rise, known as the Great Oxidation Event (GOE), occurred, implying a potential connection between these events. Herein we combine triple oxygen isotope systematics and in situ and high-precision U-Pb zircon ages of mafic intrusions to date two episodes of snowball Earth glaciations. Subglacial hydrothermal alteration was induced by intrusions of high- Mg and high-Fe gabbros during the early Paleoproterozoic rifting on the Baltic Shield, which at the time was located at low latitudes. The low d18O values of hydrothermally altered rocks associated with these intrusions are attributed to high-temperature isotopic exchange between hot rock and glacial meltwater, indicating the presence of glacial ice globally. The triple oxygen isotope approach is used here to show that the d18O of glacial meltwaters during the dated episodes of snowball Earth glaciation was approximately –40 permil VSMOW (Vienna standard mean ocean water). High-Mg gabbro intrusions and associated low-d18O hydrothermally altered rocks formed during the earliest episode of snowball Earth glaciation between 2.43 and 2.41 Ga. High-Fe gabbro from the Khitoostrov locality (Karelia, Russia) hosts a d18O value of −27.3 permil and is dated here at 2291 ± 8 Ma. This age is interpreted to reflect the interaction between the intrusion and glacial meltwaters during the third Paleoproterozoic glaciation, which occurred after the GOE.
Keywords PaleoproterozoicSnowball EarthZirconU-PbGreat Oxidation Event
Full text
Article (Published version) (297 Kb) - document accessible for UNIGE members only Limited access to UNIGE
Research group Isotope Geochemistry, Geochronology and Thermochronology
(ISO format)
ZAKHAROV, D.O. et al. Dating the Paleoproterozoic snowball Earth glaciations using contemporaneous subglacial hydrothermal systems. In: Geology, 2017, vol. 45, n° 7, p. 667-670. doi: 10.1130/G38759.1 https://archive-ouverte.unige.ch/unige:94788

457 hits

0 download


Deposited on : 2017-06-12

Export document
Format :
Citation style :