Yunlin Fm
Type Locality and Naming
The Yunlin Formation was erected by Ji Wenrong in 1983. The section for the designation is down the borehole No.2 at Beigang of the Yunlin County of Taiwan.
Lithology and Thickness
The Yunlin Formation is represented by gray white-gray sandstone, fine-grained sandstone, siltstone, shale, limestone and conglomerate and small amounts of basalt. The Yunlin Formation is 530 m thick.
Relationships and Distribution
Lower contact
Its base marked by conglomerate lies unconformably on the underlying strata (age unknown). Regionally, the next older unit is the Dananao Gr (Tianxiang Fm)
Upper contact
It is unconformably under the overlying strata. Regionally, next younger unit is the Bihou Fm
Regional extent
The formation mainly occurs under the ground of the littoral plain within the Yunlin County. It ranges from 63 to 530 m in thickness.
Fossils:
The formation yields nannofossils such as Chiastozygus litterarius, Rucinolithus irregularis, Micrantholithus obtusus, Watznaueria barnesae, Cyclagelosphaera margereli, Nannoconid minutus, N .globulus, N. truitti, etc.; ammonites Holcophylloceras caucasicum, Cheloniceras (Epicheloniceras) aff. orientale, Dufrenoyia sp.; and saline and semi-saline water bivalves Tetoria (Paracorbicula) sp., Nemocardium sp., Costocyrena peikangensis, Neithea (Neithella) sp., etc.
GeoJSON
Fossils
The formation yields nannofossils such as Chiastozygus litterarius, Rucinolithus irregularis, Micrantholithus obtusus, Watznaueria barnesae, Cyclagelosphaera margereli, Nannoconid minutus, N .globulus, N. truitti, etc.; ammonites Holcophylloceras caucasicum, Cheloniceras (Epicheloniceras) aff. orientale, Dufrenoyia sp.; and saline and semi-saline water bivalves Tetoria (Paracorbicula) sp., Nemocardium sp., Costocyrena peikangensis, Neithea (Neithella) sp., etc.
GeoJSON: { "type": "Feature", "properties": { "id": null, "NAME": "Central Taiwan (Cret. 44)" }, "geometry": { "type": "MultiPolygon", "coordinates": [ [ [ [ 120.4, 24.69 ], [ 120.69, 24.91 ], [ 121.05, 24.89 ], [ 121.17, 24.77 ], [ 121.08, 24.49 ], [ 120.87, 23.96 ], [ 120.48, 23.47 ], [ 120.06, 23.25 ], [ 119.97, 23.51 ], [ 120.02, 23.89 ], [ 120.18, 24.33 ], [ 120.4, 24.69 ] ] ] ] } }
Fossils:
None listed
Age
Depositional setting
It mainly belongs to neritic facies and partially to fluvial and delta facies deposition.
Additional Information