2004(3):332-337.
DOI: 1
CSTR:
Abstract:
Parahorologinella, as a new genus, is proposed for accepting a kind of palynomorphs found from the Denglouku Formation revealed by the boreholes Yu-302 and Yu-102 drilling in Yushu, southeastern Songliao Basin. The associated pollen and spores have been collectively named the Cicatricosisporites exilis-Hymenozonotriletes mesozoicus Assemblage which is considered to be the Albian representative of the Cretaceous sequence of North China palynoflora (Li and Liu, 1994). Lithologically the Denglouku Formation distributed in Songliao Basin is divided into 4 members. According to Gao et al. (1994), a palynological sequence including 3 assemblages from the formation may be recognized, namely, in ascending order, the Berremian-Early Aptian Cyathidites-Leiotriletes-Clavatipollenites assemblage from the members 1 and 2, the Aptian Cicatricosisporites-Leiotriletes-Polyporites assemblage from the third and the Early Albian Leiotriletes-Schizaeoisporites assemblage from the upper one. In this sequence, the first appearance of the angiosperm pollen Polyporites Mtchedlishvili is in the Member 3 (Gao et al., 1994) and the dinoflagellate cyst Vesperopsis zhaodongensis Qiao, He et Gao was found from the Member 4 (Gao et al., 1992). Significantly, these pollen (Pl.I, fig.11) and cyst (Pl.I, fig.12) are also encountered in the boreholes Yu-302 and Yu-102 together with the Parahorologinella grains. Based on the lithostratigraphical correlation and palynological comparison, the strata encountered in the holes includes only the Members 2 and 3 of the Denglouku Formation and may refers to Early to Middle Albian rather than pre-Albian in age. The palynomorph Parahorologinella only occurs in Member 3.
