Abstract:
A total of 26 species of 15 genera plant fossils have been discovered in Mangniuhai area, southern Tuquan Basin, mainly including Annelids (
Noecalamites sp. and
Equisetites sp.), Filicopsida (
Todites goeppertianus,
T.
williamsoni,
Cladophlebis argutula,
C.
hsiehiana and
C.
shansiensis), Coniferales (
Pityospermum staratschini,
P.
nordenskioldi,
Podozamites schenki and
P.
lanceolotus), Ginkgoales (
Czekanowskia rigida,
Ginkgo huttoni,
Ginkgoites cf.
sibiricus,
G.
sibiricus,
G. cf.
marginatus,
G.
lepidus,
Vittifoliolum paucinerve,
Phoenicopsis speciosa and
Sphenobailra sp.), Cycadales (
Nilssonia sinensis) and Gymnosperms seed (
Carpolithus sp.). Among them the Filicopsida (26.9%) and Ginkgoales (38.5%) are dominant, with Coniferales accounting for 19.2%, a small number of Equisetales (7.7%), Cycadales (3.8%) and Gymnosperms (3.8%) as well. Combined with the previous discovery of
Raphaelia diamensis in the area, it is revealed that the minable seam-bearing fine clastic rock assemblages have the characteristics of early Middle Jurassic, belonging to Wanbao Formation. Based on the fact that the plant assemblages mainly consist of
Cladophlebis, Ginkgoales like
Ginkgo,
Ginkgoites and
Sphenobailra, and Cycads
Podozamites, together with the flora appearance in the entire Wanbao Formation at that time, as well as the features of coal seam and developed sedimentary iron, it is inferred that the study area was in a warm and humid paleoclimate environment then.