Carbon Isotope Composition and Geochemical Features of Sediments From Gongga Mountain, China, and Potential Environmental Implications

Using gas chromatography-triple quadrupole tandem mass spectrometry (GC-MS/MS), the soluble organic matter was analyzed for first time in twenty-two sediment samples from eastern slopes of Gongga Mountain, China, at high altitudes between 4,600 and 6,700 m. The C 11 -C 33 n -alkanes 9 -alkan-2-ones were identified these samples. Both compounds dominated by odd carbon numbers long-chain molecules contained a maximum 27 or 29 , indicating that sediments predominantly higher plant origin. However, short-chain -alkan-2-ones, with content 17 i 18 (phytone, 6, 10, 14-trimethylpentadecan-2-one), did not show predominance even numbers, suggesting they derived bacteria algae. Therefore, we suggest Mountain comes three sources, i.e. bacteria, algae, plants. Stable isotope (δ 13 C) values ranged −24.6‰ to −27.3‰, 3 plants dominant input relatively colder drier depositional environment. 4 increase sharply 6,300–6,600 m, paleoclimate became wetter altitude.