Triple oxygen isotope (δ17O and δ18O) values of high- and low-temperature altered oceanic crust and products of basalt alteration experiments were measured to better constrain ocean isotope compositions in deep time. The data define an array of δ18O and Δ′17O (Δ′17O=δ′17O − λRL × δ′18O + γ) values from mantle values toward 1‰ and −0.01‰, respectively, with a λ of ~0.523. The altered oceanic crust data were used to construct a model for estimating δ18O-Δ′17O values of the ancient oceans if the continental weathering flux (FCW) and/or hydrothermal oceanic crust alteration flux (FHT) changed through time. A maximum lowering of 7‰ and 4‰, respectively, is achieved in the most extreme cases. The δ18O value of the ocean cannot be raised by more than 1.1‰. Eclogites from the Roberts Victor kimberlite (South Africa), with a protolith age of 3.1 Ga, have δ18O-Δ′17O values that precisely overlap with those of the modern altered oceanic crust, suggesting that the Archean oceans had similar isotope values as today. Published triple isotope data for Archean cherts show that all samples have been altered to some degree and suggest an Archean ocean surface temperature of ~70–100 °C. An ocean as light as −2‰ is still consistent with our eclogite data and reduce our temperature estimates by 10 °C.

中文翻译：

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太古宙炽热海洋的三重氧同位素证据

测量了高低温蚀变洋壳和玄武岩蚀变实验产物的三重氧同位素（δ17O和δ18O）值，以更好地约束深水时的海洋同位素组成。数据定义了一系列 δ18O 和 Δ′17O（Δ′17O=δ′17O - λRL × δ′18O + γ）值，从地幔值分别向 1‰ 和 -0.01‰ 变化，λ 约为 0.523。如果大陆风化通量（FCW）和/或热液洋壳蚀变通量（FHT）随时间变化，则改变的洋壳数据用于构建估算古代海洋δ18O-Δ'17O值的模型。在最极端的情况下，最大降低分别为 7‰ 和 4‰。海洋的δ18O值升高不能超过1.1‰。来自 Roberts Victor 金伯利岩（南非）的榴辉岩，原岩年龄为 3.1 Ga，δ18O-Δ′17O 值与现代变化的洋壳精确重叠，表明太古代海洋具有与今天相似的同位素值。已发表的太古代燧石三重同位素数据显示，所有样品都发生了一定程度的改变，表明太古代海洋表面温度约为 70–100 °C。轻至 -2‰ 的海洋仍然与我们的榴辉岩数据一致，并将我们的温度估计值降低了 10°C。