Conodont samples were collected from three localities in the Onoo Tolgoi area, Mongolia, and many conodonts have been found. Conodonts from the Onoo Tolgoi Formation （M288-M294） lack index fossils; its age could be ...Conodont samples were collected from three localities in the Onoo Tolgoi area, Mongolia, and many conodonts have been found. Conodonts from the Onoo Tolgoi Formation （M288-M294） lack index fossils; its age could be Late Silurian. Samples from the Hutul us hudag Formation （M295-M299） contain Ozarkodina pandora alpha Morph. （ P element）, clearly indicating that this formation is Early Devonian late Lochkovian in age. Samples collected from so-called Silurian Onoo Tolgoi Formation at other localities （M300-M303） yield many Ordovician conodonts, including Icriodella baotaensis, Icriodella cf. baotaensis, Eoplacognathus fianyeen- sis, Eoplacognathus protoramosus ; Baltoniodus alobatus ; and ？ Ambalodus triangularis ; the age is Late Ordovician, more precisely, early-middle Late Ordovician.展开更多
Conodont Caudicriodus angustus angustus （Steward et al. , 1956 ） and Catuticriodus angustus cauda （Wang et al. , 2005） were found from a big limestone lens of the Berh Hairhan Formation in the place of W 150 km to...Conodont Caudicriodus angustus angustus （Steward et al. , 1956 ） and Catuticriodus angustus cauda （Wang et al. , 2005） were found from a big limestone lens of the Berh Hairhan Formation in the place of W 150 km to Ulaanbaatar City. The discovery indicates that the Beth Haihan Formation should be assigned to Middle Devonian Eifelian Stage. This conodont fauna was from a shallow cooler water facies in the relatively high latitude.展开更多
文摘Conodont samples were collected from three localities in the Onoo Tolgoi area, Mongolia, and many conodonts have been found. Conodonts from the Onoo Tolgoi Formation （M288-M294） lack index fossils; its age could be Late Silurian. Samples from the Hutul us hudag Formation （M295-M299） contain Ozarkodina pandora alpha Morph. （ P element）, clearly indicating that this formation is Early Devonian late Lochkovian in age. Samples collected from so-called Silurian Onoo Tolgoi Formation at other localities （M300-M303） yield many Ordovician conodonts, including Icriodella baotaensis, Icriodella cf. baotaensis, Eoplacognathus fianyeen- sis, Eoplacognathus protoramosus ; Baltoniodus alobatus ; and ？ Ambalodus triangularis ; the age is Late Ordovician, more precisely, early-middle Late Ordovician.
文摘Conodont Caudicriodus angustus angustus （Steward et al. , 1956 ） and Catuticriodus angustus cauda （Wang et al. , 2005） were found from a big limestone lens of the Berh Hairhan Formation in the place of W 150 km to Ulaanbaatar City. The discovery indicates that the Beth Haihan Formation should be assigned to Middle Devonian Eifelian Stage. This conodont fauna was from a shallow cooler water facies in the relatively high latitude.
