Fig. 6From: Palaeoenvironmental setting of lacustrine stromatolites in the Miocene Wudaoliang Group, northern Tibetan PlateauBimodal distribution pattern of the relative abundance of normal alkane detected in the stromatolite samples ranging from the mid-chain n-alkanes (C19 to C24) to the long-chain n-alkanes (C25 to C35). Note the predominance of odd-numbered n-alkanes over even-numbered n-alkanes in their relative abundance range in the range of C25-C33. Long-chain odd-numbered n-alkanes (C25, C27, C29, C31) could indicate the presence of higher plants in the vicinity of the depositional environment. See further explanation from the calculated index results in Table 7Back to article page