# Eocene Sedimentary-Diagnetic Environment Analysis of the Pingtai Area of the Qaidam Basin
## 5 Elemental Geochemistry
### Major Element Analysis
\begin{table}
\begin{tabular}{c c c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Fm**} & **Buried** & \multirow{2}{*}{**Lithology**} & \multirow{2}{*}{**Lithology**} & \multirow{2}{*}{**Lithology**} & \multirow{2}{*}{**Na\({}_{2}\)O**} & \multirow{2}{*}{**MgO**} & \multirow{2}{*}{**Al\({}_{2}\)O\({}_{3}\)**} & \multirow{2}{*}{**SiO\({}_{2}\)**} & \multirow{2}{*}{**K\({}_{2}\)O**} & \multirow{2}{*}{**CaO**} & \multirow{2}{*}{**Fe\({}_{2}\)O\({}_{3}\)**} & \multirow{2}{*}{**P\({}_{2}\)O\({}_{5}\)**} & \multirow{2}{*}{**TiO\({}_{2}\)**} & \multirow{2}{*}{**MnO\({}_{2}\)**} & \multirow{2}{*}{**LOI**} \\  & **(m)** & & & **(\%)** & & & & & & & & \\ \hline \multirow{6}{*}{**C**} & 644.77 & Brown-red mudstone & 0.92 & 8.67 & 12.82 & 33.87 & 2.79 & 18.97 & 5.99 & 0.04 & 0.68 & 0.10 & 14.72 \\  & 645.77 & Brown-red mudstone & 1.20 & 5.71 & 17.30 & 48.67 & 3.48 & 6.43 & 8.33 & 0.11 & 0.74 & 0.10 & 7.86 \\  & 647.76 & Brown-red mudstone & 1.63 & 3.80 & 13.29 & 51.25 & 2.25 & 9.49 & 5.48 & 0.09 & 0.72 & 0.13 & 11.44 \\  & 648.26 & Brown-red mudstone & 1.10 & 6.32 & 12.23 & 37.86 & 2.44 & 17.35 & 5.68 & 0.20 & 0.68 & 0.11 & 15.34 \\  & 648.76 & Brown-red mudstone & 1.03 & 4.85 & 12.64 & 37.27 & 2.62 & 19.94 & 5.49 & 0.05 & 0.73 & 0.11 & 14.71 \\  & 649.76 & Brown-red mudstone & 1.24 & 3.29 & 12.32 & 44.03 & 2.32 & 15.73 & 4.99 & 0.11 & 0.74 & 0.13 & 14.42 \\  & 650.26 & Brown-red mudstone & 1.66 & 4.23 & 12.18 & 59.85 & 2.76 & 4.46 & 6.49 & 0.13 & 0.72 & 0.10 & 7.29 \\  & 651.26 & Brown-red mudstone & 1.20 & 3.74 & 13.99 & 45.53 & 2.72 & 12.64 & 5.57 & 0.21 & 0.72 & 0.11 & 13.09 \\  & 652.26 & Brown-red mudstone & 1.42 & 4.29 & 15.08 & 48.70 & 2.80 & 9.69 & 6.34 & 0.11 & 0.75 & 0.11 & 10.25 \\  & 653.26 & Brown-red mudstone & 1.43 & 3.69 & 14.09 & 48.85 & 2.58 & 11.05 & 5.54 & 0.10 & 0.75 & 0.12 & 11.58 \\ \cline{2-13}  & & Average & 1.28 & 4.86 & 13.59 & 45.59 & 2.68 & 12.58 & 5.99 & 0.12 & 0.72 & 0.11 & 12.07 \\ \cline{2-13}  & 928.23 & Grayish-brown siltstone & 1.68 & 1.45 & 9.42 & 72.30 & 1.68 & 3.14 & 3.00 & 0.09 & 0.51 & 0.13 & 5.84 \\  & 929.68 & Grayish-brown siltstone & 3.08 & 0.95 & 11.54 & 71.12 & 2.38 & 4.31 & 2.62 & 0.05 & 0.21 & 0.13 & 3.41 \\  & 995.8 & Grayish-white fine sandstone & 1.87 & 1.01 & 7.95 & 66.47 & 1.50 & 7.59 & 2.3 & 0.06 & 0.47 & 0.14 & 9.89 \\  & 997.3 & Grayish-white medium sandstone & 2.55 & 1.36 & 10.16 & 68.68 & 1.73 & 5.42 & 2.87 & 0.07 & 0.49 & 0.13 & 6.17 \\  & 998.28 & Grayish-white medium sandstone & 2.71 & 0.93 & 10.64 & 65.26 & 1.90 & 7.67 & 3.95 & 0.07 & 0.26 & 0.22 & 6.27 \\  & 1000.88 & Grayish-white conglomerate & 2.67 & 0.86 & 10.61 & 66.35 & 2.29 & 7.45 & 2.7 & 0.06 & 0.23 & 0.14 & 5.95 \\  & 1002.28 & Brown-red mudstone & 0.98 & 5.59 & 10.28 & 62.43 & 4.31 & 4.64 & 3.68 & 0.19 & 0.74 & 0.12 & 7.77 \\  & 1002.78 & Brown-red mudstone & 1.19 & 4.56 & 15.18 & 59.95 & 3.46 & 4.55 & 3.15 & 0.14 & 0.70 & 0.11 & 7.95 \\ \hline \multirow{6}{*}{**C**} & \multirow{2}{*}{Average} & 2.09 & 2.09 & 10.72 & 66.5 & 2.41 & 5.60 & 3.03 & 0.09 & 0.45 & 0.14 & 6.66 \\ \cline{1-1}  & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & & & \\ \cline{1-1}  & & & & & & & & & & & & & & & \\ \hline \end{tabular}
\end{table} 
Table 2: Major oxide contents of the Eocene in the Pingtai area. Loss on ignition not only indicates the deposition process of organic matter and carbonate, but also reflects the input of terrestrial organic matter and the production and preservation capacity of organic matter in the lake [52; 53; 54; 55; 56; 57]. Climate and environment are the main factors affecting the productivity and preservation of lake organic matter. Under cold and dry conditions, the land-based input to the lake decreases and the productivity of organic matter decreases; this is not conducive to the preservation of organic matter and will reduce loss on ignition. On the contrary, loss on ignition will increase under warm and humid climate conditions [58].