Chuandishan Fm

East Heilongjiang and East Jilin. The reference section is located at the Chuandishan Hill in Huadian City, Jilin Province. The formation was named by Liu Yuchu et al. in 1953 (unpublished), but no name section was nominated. In 1978 the section was resurveyed by the Geological Survey Team of Jilin Province (Team One). Geographical coordinates of the type section: 43°02′00″N—126°59′00″E (GPS).

See Additional Information for discussion of use of "Chaundishan Fm" for regional volcanics.

It is characterized by the primary compact massive basalt, mugearite, vesicular basalt and amygdaloidal basalt, with three interbeds of volcanic-clastic sedimentary rocks. Four cycles of basic-alkaline eruption may be recognized. This formation usually forms platforms and table mounts, 800–1400 m above sea level. The thickness is 86 m in the reference section and varies from several meters to 500 m in the district.

Lithology and Thickness:

It is characterized by the primary compact massive basalt, mugearite, vesicular basalt and amygdaloidal basalt, with three interbeds of volcanic-clastic sedimentary rocks. Four cycles of basic-alkaline eruption may be recognized. This formation usually forms platforms and table mounts, 800–1400 m above sea level. The thickness is 86 m in the reference section and varies from several meters to 500 m in the district.

Lithology-pattern: Volcanics

Relationships and Distribution:

Lower contact:

The Chuandishan Fm is in unconformable contact with the underlying Tumenzi Fm or Fujin Fm.

Upper contact:

The Chuandishan Fm is in unconformable contact with the overlying Quaternary Junjianshan Fm.

Regional extent:

The Chuandishan Fm is distributed in Huadian City, east of Jilin Province, and in Heilongjiang Province as well.

GeoJSON:

Fossils:

Age:

Dating of the Chuandishan basalt on Top of the type section in 2009 indicated that the whole rock age of K-Ar is (28.3±2.3) Ma. [However, the underlying Fujin Fm (Songliao) or Tumenzi Fm (Jilin) are interpreted as Miocene; therefore, there is a conflict.]

Age Span:

Beginning stage: Tortonian

Fraction up in beginning stage: 0.0

Beginning date (Ma):

Ending stage: Zanclean

Fraction up in ending stage: 1.0

Ending date (Ma):

Depositional setting:

Depositional-pattern:

Additional information

The high-position basalts are formed many times in Northeast China from Paleocene to Pliocene, and all the basalts were named “Chuandishan basalt” for a long period, because there was no isotopic dating of the type section for more than half a century. In Lithostratigraphy of Jilin Province, it was suggested using “Chuandishan basalt” to summarize all the Neogene basalts. However, the dating of the Chuandishan basalt on top of the type section in 2009 indicated that the whole rock age of K-Ar is (28.3±2.3) Ma. Combined with other documents, the Chuandishan basalt can be recognised as an event stratigraphic unit, or it can be considered in board sense as a volcanic stratigraphic unit formed by volcanic events in late Oligocene sedimentation. Thus, it is improper to use “Chuandishan basalt” to infer the Neogene basalts now, but there is no further study on the modifications of the Miocene and Pliocene basalts and other strata. So we follow the old definition here before the overall revision of Cenozoic stratigraphy in Northeast China.