These rocks contained dolomite, clay minerals, quartz, tuffaceous matrix, tuff debris, calcite, ferruginous debris, siliceous debris and anorthose
. The key sequence stratigraphy boundaries were identified and oil shale was mainly deposited in transgressive and highstand systems tracts.
Quartz, ankerite, and anorthose
are the main rock-forming minerals of the sandstone.
The relative contents of minerals (%) Area Quartz Alkali feldspar Anorthose
Calcite Gonghe Basin 39 14 18 1 Monkey Ridge 27 18 26 0 The relative contents of minerals (%) Area Amphibole Andreattite Kaolinite Chlorite Gonghe Basin 2 18 4 4 Monkey Ridge 0 29 0 0 Table 2: Rock parameters of the granodiorite samples from the Jilin Monkey Ridge area and the Gonghe Basin of Qinghai.
Similarly, the proportion of anorthose
grains in total feldspar grains declined with depth, while that of K-feldspar grains increased, when the depth was less than 2800 m (Figure 4).
It mainly consists of anorthose
, hornblende, potassium feldspar, biotite, quartz and a few monoclinic pyroxenes and metallic minerals.
Depth Mineral content (%) Quartz Potassium Soda Anorthose Anorthose
feldspar feldspar 3645.10 51.7 0.8 0.2 3649.83 60.8 1.2 0.4 3666.00 48.5 1.9 0.3 1.4 Depth Mineral content (%) Dolomite Iron Hematite TCCM pyrite 3645.10 2.7 44.6 3649.83 4.7 32.9 3666.00 4.5 43.4 TABLE 4: Clay mineral composition and content of the Nahr Umr Shale.