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Based on gas composition and temperature measurements in the course of field drilling, the upper and lower depths of gas hydrate stability zone are calculated by modeling in the Muli permafrost, Qinghai, then the modeling results are compared with the drilling results. The modeling results show that the upper depth of gas hydrate stability zone is 148.8~122.7 m and the lower depth of gas hydrate stability zone is 324.6~354.8 m, with the thickness of gas hydrate stability zone of 175.8~232.2 m; the drilling results indicate that gas hydrate and its related indications occur at the interval of 133~396 m. These two types of results are comparable and thus are basically accordant, suggesting that the modeling can serve as a prediction of the upper and lower depths of gas hydrate stability zone. Gas composition, depth of permafrost, thermal gradients above and below the base of permafrost are sensitive factors affecting the upper and lower depths of gas hydrate stability zone in the Muli permafrost.

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Enclaves in intermediate‐acid plutons from Tongling can be divided into three types: xenoliths, relics and magmatogenic enclaves. The magmatogenic enclaves consist of cumulates, micrograined dioritite mixtite and dioritic chilled border enclaves. Petrologically, relics with eyed and meta‐poikilitic texture are characterized by high content of biotite (>80%) and low content of cordierite and grossular. The cumulates with accumulate texture consist of a great amount of pyroxene, hornblende and minor spinel and phlogopite. The micrograined dioritic mixtite is composed of more hornblendes and feldspar and less needle apatites and an ellipsoid basic core included in plagioclase. The chilled border enclaves have the same mineral association, but more dark minerals than the host rocks consisting of plagioclase, quartz, alkaline feldspar, hornblende and biotite. Geochemically, the relics exhibit high REE content (455.8×10−6) and high ratio of LREE/HREE, more obvious Eu negative anomaly and are rich in Cr and Ni, poor in Ba, Nb and Sr. All kinds of magmatogenic enclaves have the same REE pattern without Eu anomaly, and the total REE is 74.9×10−6 for spinel pyroxene cumulate, 179.7×10−6 for hornblende cumulate, 226.9 × 10−6 for hornblende cumulate crystal, 289.9×10−6 for micrograined dioritic mixtite and 131.2×10−6 for chilled border enclaves. Calculation with the thermometer and barometer for minerals shows that the temperature and pressure of formation are 1126 °C and 8.44 kbar (7.15–9.04 kbar) for the spinel pyroxene cumulate, 1065 °C‐1029 °C and 8.23 kbar (7.13–9.50 kbar) for the hornblende pyroxene cumulate, 959 °C and 3.40 kbar (2.86–4.09 kbar) for the micrograined dioritic mixtite enclaves, and 951 °C and 0.59 kbar for the dioritic chilled border enclaves, respectively. Thus, the following conclusions can be drawn. Relic enclaves were derived from the crustal partial melting and all cumulate enclaves originated from deep magma chambers near the Moho in the lower crust, which are cumulate fragments formed by fractional crystallization of basic magma; mixtite came from shallow magma chambers in the middle‐upper crust, formed by the mixture of mantle‐derived magma and acid magma derived from the crustal partial melting; and the chilled border enclaves came from the border fragments of early intrusive bodies.