火星大气的同位素比值 [天] isotopic ratio in Mars atmosphere
气体采样中的氪和氙同位素比值产生了一个令人吃惊的结果：这些比值跟在形成太阳系的原始云团中所发现的比值不一致。
The krypton and xenon isotope ratios in the gas samples provided a surprising result: They did not match the ratios found in the primordial cloud that spawned the solar system.
证据就存在于海洋泥土，花粉化石和记录温度变化的化学同位素比值变化之中。
The evidence lies in ocean mud, in fossil pollen, and in changes in ratio of chemical isotopes that record shifts in temperature.
壳型花岗岩具较高的铅同位素比值和富铀铅贫钍铅的特点；
The crust granites have higher lead isotope ratios and are richer in uranium lead but poorer in thorium lead.
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