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微生物的污染物在露头上和实验室内均可混入。微体化石既有天然的亦有人造的。这种令人迷惑的物体是可以辨认的,更重要的是不能允许它们削弱日益增多的前显生宙可信的有生命存在的记录。巴西的(约10亿年)和南非的(约23亿年)古老的碳酸盐岩石标本微小裂隙内所发现的丝状微生物污染物,与以前描述为化石的产状相类似。已发表的有可能属太古代的微生物同样包括了微体污染物和实验室里人工制品。虽然斯瓦士兰统沉积岩的微结构可能是化石,但它们还没有得到验证。至今已知最老的保存化石结构的是洛伊丝、纳吉(Lois,Nagy)所描述的约23亿年的南非泥灰质白云岩、迭层石灰岩内的丝体。由于缺少确切的有关超微结构或微量化学方面的证据,因此难以确定那些较老的化石记录是肯定无误的。
Microbial contaminants can be mixed in outcrops and labs. Microbial fossils are both natural and man-made. Such obscure objects are identifiable and, more importantly, can not allow them to undermine the credible existence of living beings in the growing Preannage. Filamentous microbial contaminants found in tiny cracks in ancient carbonate rock samples from Brazil (about 1 billion years) and South Africa (about 2.3 billion years) are similar to those previously described as fossils. Published organisms that may be Archean also include microbial contaminants and laboratory artifacts. Although the microscopic structure of the Swabian sediments may be fossils, they have not yet been validated. The oldest preserved fossil structure known to date is about 2.3 billion years of South African marl dolomite described by Lois, Nagy, superimposed with filaments in limestone. Due to the lack of exact evidence on ultrastructure or microchemistry, it is difficult to determine which older fossil records are unmistakable.