Dongla Gr
Type Locality and Naming
The type section is located at Dongla, about 35 km north of Jomda County, Xizang. It was named by Li Pu et al. in 1955.
Lithology and Thickness
Volcanic rocks. This Group is a set of massive to thick-bedded pyroclastic rock and volcanic rock. The lithology is mainly composed of light-gray, grayish-green to grayish-black rubbly tuffs, rhyolite and clay slate. The thickness is more than 1700 m.
Relationships and Distribution
Lower contact
The contact relationships of the Dongla Group with the underlying formations are not yet clear, due to the incomplete exposures at the bottom and the top of the group. However, a follow-up survey indicated a conformable contact with the underlying Middle Devonian (the Dingzonglong Fm).
Upper contact
The contact relationships of the Dongla Group with the overlying formations are not yet clear, due to the incomplete exposures at the bottom and the top of the group. However, a follow-up survey indicated an upper disconformable contact relationship with the overlying Upper Triassic.
In the area of Tuka in Dêqên County, the group has a disconformable contact with the overlying Machala Fm of the Visean Stage [Not in Carboniferous English Lexicon].
Regional extent
This group is distributed from Dongla to Tuka in Dêqên County along the Jinshajiang River.
GeoJSON
Age
Depositional setting
It is interpreted as a volcanic eruption facies deposit.
Additional Information