对于人类生命和适宜的地球大气气候,碳是一个至关重要的元素。地球上大于90%的碳储存在地球深部,强烈地影响深部地幔的组成、结构和氧逸度。由于碳存在多种价态(-4到+4),因而在自然界中可以与多种元素结合,这使得碳在地质过程中表现很活泼。同时在地球初始的增生过程和后期的分异过程中碳的行为复杂,这使得我们对地球深部碳的丰度和动力学行为了解甚少。碳同位素可以很好地记录和示踪地球表层和深部的碳循环过程。最近,美国德州理工大学地球科学学院Horita教授和他的合作者计算了碳化铁和碳化硅中碳同位素 Carbon is a vital element for human life and the right Earth’s atmosphere. More than 90% of the Earth’s carbon is stored deep in the Earth, strongly affecting the composition, structure and oxygen fugacity of the deep mantle. Because carbon has multiple valence states (-4 to +4), it can be combined with various elements in nature, which makes carbon behave very actively in geological processes. At the same time, the behavior of carbon in the process of initial and later differentiation of the earth is complex, which makes us have little understanding of the abundance and dynamics of deep earth carbon. Carbon isotopes are good at recording and tracing the surface and deep carbon cycles of the earth. Recently, Professor Horita and his collaborators at the Texas Tech University School of Geosciences calculated the carbon isotopes of iron carbide and silicon carbide