Signals of combined chromium–cadmium isotopes in basin waters of the Early Cambrian – Results from the Maoshi and Zhijin sections, Yangtze Platform, South China

Constraining Shallow Seawater Oxygenation for the Yangtze Platform During the Early Cambrian

“…These elevated δ 53 Cr values of the Yanjiahe and lower Shuijingtuo Formations correspond well with previously reported δ 53 Cr data for sediments deposited during the Ediacaran-early Cambrian transition from the Yangtze Block (Frank et al, 2019;Frei et al, 2020Frei et al, , 2021Wei, Frei, et al, 2020), suggesting that they are representative of the local water conditions at that time. The carbonates of the Zhujiaqing Formation, which is time equivalent to the Yanjiahe Formation, recorded a trend of decreasing δ 53 Cr auth values with increasing authigenic Cr concentrations (Wei, Frei, et al, 2020).…”

A two-stage Cd purification method with anion exchange resin and BPHA extraction resin for high precision determination of Cd isotopic compositions by double spike MC-ICP-MS

“…[4][5][6][7] Additionally, Cd isotopes are broadly utilized to study the biological cycling of Cd in the marine environment, [8][9][10][11][12][13] to reconstruct the Cd isotopic composition of seawater, 14,15 and levels of primary productivity of paleoceanography. [16][17][18] With the increasing Cd pollution problems, the sources and fates of Cd in surface environments are traced with Cd isotopic ngerprint information. [19][20][21][22][23][24][25][26][27][28] Cd isotopic ratios were rst measured by TIMS obtaining an external precision for d 114/110 Cd of 3.2-6.4& (2SD), which cannot distinguish Cd isotopic fractionation in most geological/ environmental samples from the experimental standard.…”

“…4–7 Additionally, Cd isotopes are broadly utilized to study the biological cycling of Cd in the marine environment, 8–13 to reconstruct the Cd isotopic composition of seawater, 14,15 and levels of primary productivity of paleoceanography. 16–18 With the increasing Cd pollution problems, the sources and fates of Cd in surface environments are traced with Cd isotopic fingerprint information. 19–28…”

High-precision measurement of Cd isotopes in ultra-trace Cd samples using double spike-standard addition MC-ICP-MS

“…4,5 In recent decades, beneting from technological advancements in multiple-collector inductively couple plasma mass spectrometry (MC-ICP-MS) and multiple-collector thermal ionization mass spectrometers (MC-TIMS), the measurement precision of Cd isotopes (d 114/110 Cd) has been improved to 0.030-0.15& (2 standard deviation, 2SD). [6][7][8][9][10][11][12][13][14][15][16][17] Thus, Cd isotopes have been developed as a powerful proxy for constraining oceanic primary productivities, [18][19][20][21][22] reconstructing the biological extinction and anoxic evolution in paleo-environment, [23][24][25][26] deciphering the sources and transport pathways of Cd in the surface environment, 27 and understanding the mechanisms of Cd uptake, transport, and accumulation in biological samples. [28][29][30][31] However, since Cd content in igneous rocks such as peridotite (0.05 mg g −1 ), basalts (0.15 mg g −1 ), and granite (0.10 mg g −1 ) is commonly lower, 32 its contents of Earth's continental crust and primitive mantle have been estimated to be 0.13 mg g −1 and 0.04 mg g −1 , respectively.…”