Uranium isotopes as a possible tracer of terrestrial authigenic carbonate

Comparison of Sr, Pb, and U isotopic compositions of bottled mineral waters produced in Romania and other European countries for authentication

“…The higher 234 U level of water from Bicazu Ardelean is due to the different chemical nature of the rock-forming minerals of the ysh deposited in the Carpathian embayment of Alpian Thetys (Sotak et al 2013), these formations contain carbonaceous and highly weathered rocks. These conditions do not support the differential wash-out of 234 U, but instead, preferential 234 U precipitation may have occurred (Rovan et al, 2021). The Sr isotopic composition of is also markedly different in the two samples despite being a few hundred meters away from each other.…”

“…Based on the alpha recoil model of 238 U ssion, leading to a disequilibrium in 234 U/ 238 U described by many authors (Fleischer 1983, Fleischer andRaabe 1978) and reviewed by Petit et al (1985) Besides alpha recoil-based washout, the concentration of 238 U can also increase due to the preferential precipitation of 234U in carbonate rocks (Rovan et al 2021). Changes in both directions can occur in hydrogeological processes.…”

“…U isotopes are good tracers of hydrogeologic processes because the relative abundance of 234 U in rocks is highly dependent on hydrothermal and surface water-related weathering (Fujikawa, 2000, Borylo andSkwarzek, 2014). The relative abundance of the isotopes 235 U and 238 U is not variable beyond the level of uncertainty of single-collector ICP-MS instrumentation (Rovan et al, 2021). U isotope fractionation not related to the radioactivity of this element (chemical mass fractionation) is not observable with single collector instruments.…”

Detrital Carbonate Minerals in Earth's Element Cycles

“…However, detrital carbonates are commonly observed constituents of suspended sediments in rivers (Mackenzie & Garrels, 1966 ; Müller et al., 2021a ) and even authigenic carbonate production in calcite‐saturated rivers is common (Grosbois et al., 2001 ; Kempe & Emeis, 1985 ; Négrel & Grosbois, 1999 ). Such authigenic carbonate formation on land represents a (temporary) sink of weathering‐derived cations, alkalinity, and carbon with implications for the location of gas exchange and for global mass balancing (Rovan et al., 2021 ; Zhao et al., 2016 ). Sr‐isotopic constraints suggest that 30%–50% of the carbonate minerals within the Gulf of Lyon sediments are detrital, even more during glacial periods (Pasquier et al., 2019 ).…”

Detrital carbonate minerals in Earth's element cycles

“…However, detrital carbonates are commonly observed constituents of suspended sediments in rivers (Mackenzie & Garrels, 1966;Müller et al, 2021a) and even authigenic carbonate production in calcite-saturated rivers is common (Grosbois et al, 2001;Kempe & Emeis, 1985;Négrel & Grosbois, 1999). Such authigenic carbonate formation on land represents a (temporary) sink of weathering-derived cations, alkalinity, and carbon with implications for the location of gas exchange and for global mass balancing (Rovan et al, 2021;Zhao et al, 2016). Sr-isotopic constraints suggest that 30%-50% of the carbonate minerals within the Gulf of Lyon sediments are detrital, even more during glacial periods (Pasquier et al, 2019).…”