Science. 1993 Mar 19;259(5102):1733-6. doi: 10.1126/science.259.5102.1733.
An oxygen isotope profile of the 2-billion-year-old Purtuniq ophiolite overlaps with similar profiles of younger ophiolites and the modern oceanic crust. This overlap implies (i) that there was a similar style of seawater-ocean crust interaction during the past 2 billion years; (ii) that the oxygen isotope composition of early Proterozoic seawater was similar to the modern value; (iii) that early Proterozoic sea-floor spreading rates were similar to, or greater than, average modern rates; and (iv) that early Proterozoic carbonate rocks and cherts with low (18)O/(16)O ratios do not reflect global-scale (18)O depletion of early Proterozoic oceans.
20 亿年前的普图尼克蛇绿岩的氧同位素剖面与年轻蛇绿岩和现代海洋地壳的相似剖面重叠。这种重叠意味着：(i) 在过去的 20 亿年中，存在着类似的海水-海洋地壳相互作用模式；(ii) 早元古代海水的氧同位素组成与现代值相似；(iii) 早元古代海底扩张速度与现代平均速度相当或更高；以及 (iv) 具有低 (18)O/(16)O 比值的早元古代碳酸盐岩和燧石并不反映早元古代海洋的全球范围 (18)O 消耗。
