这是一个全球性的记录：在取自不同大陆位置的沉积标本中，同位素比率的变化非常小。
It is a global record: there is remarkably little variation in isotope ratios in sedimentary specimens taken from different continental locations.
同位素比率直接用于比较各种石油或天然气。
The isotope ratio is directly used for comparing oils or gases.
其中一个方法判断生活的来源是通过测量气体同位素比率。
One way to tell if life is the source of the gas is by measuring isotope ratios.
随之而来勃发的浮游生物吸走了12c，碳同位素比率转向相反方向。
The subsequent plankton bloom sucked up the 12c and the isotope ratio veered off in the opposite direction.
怀特塞德博士发现，当大陆割裂熔岩开始涌出时，碳同位素比率就像醉酒水手一样偏离航线。
Dr Whiteside found the ratio yawed around like a drunken sailor as the continents split apart and the lava started pouring out.
随着大量的水通过蒸发被抽离，并以雪的形式沉淀形成冰川冰，海洋中氧同位素的比率就发生了变化。
The oxygen isotope ratio of the ocean changes as a great deal of water is withdrawn from it by evaporation and is precipitated as snow to form glacial ice.
研究人员对间冰期气候的线索来自保存在GRIP 冰芯中的两种略微不同类型的氧——即同位素氧-16和氧-18的比率。
Researchers' clues to the Eemian climate come from measurements of the ratios of two slightly different types of oxygen, isotopes oxygen-16 and oxygen-18, preserved in the GRIP core.
但是研究团队发现在月球上氯的同位素的比率大约是地球上的25倍。
But the team found that on the Moon it was about 25 times that of the terrestrial chlorine isotope ratio.
他们然后使用当地的降雪记录来寻找有气象记录的年代里降雪量和树木年轮中氧元素同位素的比率之间的关系。
They then used local snowfall records to find the relationship between precipitation and the proportion of heavy oxygen in tree rings for the years covered by the weather records.
夏普博士说如果月球岩石中氢的初始含量接近地面的岩石，氯同位素比例比率不会这么分散。
Dr Sharp said that if lunar rocks had initial hydrogen contents anywhere close to those of terrestrial rocks, the chlorine isotope ratios would not have so much scatter.
标准模式理论会很清楚地预测到这3中元素的多种同位素出现的比率。
The Standard Model makes clear predictions for the ratios of various isotopes of all three.
所谓同位素构成，是指在某一元素的特定样品中该元素不同同位素的百分比率。同位素构成因此特别适合于作为铜矿厂来源的示踪物。
Isotopic composition, the percentages of the different isotopes of an element in a given sample of the element, is therefore particularly suitable as an indicator of the sources of the ore.
所谓同位素构成，是指在某一元素的特定样品中该元素不同同位素的百分比率。同位素构成因此特别适合于作为铜矿厂来源的示踪物。
Isotopic composition, the percentages of the different isotopes of an element in a given sample of the element, is therefore particularly suitable as an indicator of the sources of the ore.
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