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Re: New-ish Papers
Liu, Y., Liu, Y., and Zhang, H. 2006. LA-ICPMS zircon U-Pb dating in the
Jurassic Daohugou Beds and correlative strata in Ningcheng of Inner
Mongolia. Acta Geologica Sinica (English Edition) 80(5):733-742.
ABSTRACT: LA-ICPMS Zircon U-Pb dating is applied to volcanic rocks
overlying and underlying the Salamander-bearing bed in the Daohugou beds
of Ningcheng in Inner Mongola and Reshuichang of Lingyuan and Mazhangzi of
Jianping in western Liaoning. The results indicate that the youngest age
of the rocks in Daohugou of Ningcheng is 158 Ma, and the oldest one is 164
Ma. Synthesized researches indicate that the salamander-bearing beds in
Daohugou of Ningcheng, Reshuichang of Lingyuan and Mazhangzi of Jianping
were developed in the same period. The Daohugou beds were formed in the
geological age of 164-158 Ma of the middle-late Jurassic. Whilst, the
Daohugou beds and its correlative strata should correspond to the
Tiaojishan Formation (or Lanqi Formation) of the middle Jurassic in
northern Hebei Province and western Liaoning Province, based on the
disconformity between the Daohugou beds and its overlaying beds of the
Tuchengzi Formation of Late Jurassic and the Jehol Beds of early
Cretaceous, and the disconformity between the Daohugou Beds and its
underlying Jiulongshan Formation, which is composed of conglomerate,
sandstone, shale with coal and thin coal beds.
- How can it be 164 Ma old, when the underlying Jiulongshan Fm is only 159
- Why do they claim the Tuchengzi Fm is Late Jurassic? A radiometric date
from its "upper part" is 140 Ma -- that's the Berriasian-Valanginian
boundary, well within the Early Cretaceous.
- If the Tuchengzi Fm really overlies the Daohugou Beds, however, that is
[...] the (ascending order) Revueltian, Apachean, Wassonian and Dawan
land-vertebrate faunachrons (LVF).
Cool. The first two or three are named after the southwest USA, and Dawa is
in China... that's Pangea for us, I guess...
The last collisional events of the Uralian orogeny took place during the
Triassic and Early Jurassic time.
A revised Milankovitch cyclostratigraphy based on new core and field data
constrains the duration of eastern North America basaltic flows to 610 ky
after the Triassic-Jurassic palynological turnover event.
Palynological data indicates correlation of the initial carbon isotopic
excursion of Hesselbo et al. [...] at St. Audrie's Bay to the
palynological turnover event and vertebrate extinction level in eastern
North America, suggesting a revised magnetostratigraphic correlation and
robust carbon isotopic tests of the Marzoli-Knight hypothesis.
We conclude that as yet there are no compelling data showing that any of
the CAMP predated or was synchronous with the Triassic-Jurassic extinction
The putative tsunamite in Northern Ireland is succeeded by a
desiccation-cracked hiatus which may correlate with a similar hiatus
truncating the seismite at sites in southern England. The hiatus in
southern England correlates closely with a d13C isotope excursion that has
been traced from eastern Europe across to western North America and is
associated with significant biotic changes.