[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

Junggar Basin Jurassic climate + earliest Paleocene stratum in China (free pdfs)



From: Ben Creisler
bcreisler@gmail.com

Two recent papers in English-language versions of Chinese journals
that may be of interest. The pdfs are free.

(This pdf may take a  little time to download.)

Shun-Li Li, Xing-He Yu, Cheng-Peng Tan & Ronald Steel (2014)
Jurassic sedimentary evolution of southern Junggar Basin: Implication
for palaeoclimate changes in northern Xinjiang Uygur Autonomous
Region, China.
Journal of Palaeogeography   3(2): 145-161
DOI:  10.3724/SP.J.1261.2014.00049
http://www.journalofpalaeogeography.org/EN/abstract/abstract61.shtml#


Junggar Basin, located in northern Xinjiang, presents continuous and
multi-kilometer-thick strata of the Jurassic deposits. The Jurassic
was entirely terrestrial fluvial and lacustrine deltaic sedimentation.
Eight outcrop sections across the Jurassic strata were measured at a
resolution of meters in southern Junggar Basin. Controlling factors of
sedimentary evolution and palaeoclimate changes in Junggar Basin
during the Jurassic were discussed based on lithology, fossils and
tectonic setting. In the Early to Middle Jurassic, the warm and wide
Tethys Sea generated a strong monsoonal circulation over the central
Asian continent, and provided adequate moisture for Junggar Basin.
Coal-bearing strata of the Badaowan, Sangonghe, and Xishanyao
Formations were developed under warm and humid palaeoclimate in
Junggar Basin. In the late Middle Jurassic, Junggar Basin was in a
semi-humid and semi-arid environment due to global warming event.
Stratigraphy in the upper part of the Middle Jurassic with less plant
fossils became multicolor or reddish from dark color sediments. During
the Late Jurassic, collision of Lhasa and Qiangtang Block obstructed
monsoon from the Tethys Sea. A major change in climate from semi-humid
and semi-arid to arid conditions took place, and reddish strata of the
Upper Jurassic were developed across Junggar Basin.

===


LI WeiTong, LIU GengWu, Dennis R. BRAMAN, LI YiBin, CAO WeiSheng, Don
BRINKMAN, SHEN Jiao & CHEN QingBao (2014)
A potential stratotype for the regional lowermost stage of the
continental Paleocene in China.
SCIENCE CHINA Earth Sciences, 2014, 57(5): 1109-1116 |
doi:10.1007/s11430-013-4746-7
http://earth.scichina.com:8080/sciDe/EN/abstract/abstract513909.shtml



Phanerozoic chronostratigraphic units can only be defined through
their lower boundary stratotypes. The lowermost stage of the Paleocene
of China, which mainly consists of terrestrial deposits, can only be
defined through its lower boundary stratotype, i.e. the continental
Cretaceous/Paleogene boundary stratotype. There is no section yet
found which contains continuous terrestrial deposits and
biostratigraphic records of the Cretaceous-Paleogene transition in
Nanxiong, Guangdong and Jiayin, Heilongjiang, there is no evidence for
establishing the continental stratotype of the Cretaceous/Paleogene
boundary in either area. Therefore, both the "Shanghuan stage" and
"Furaoan stage" are not good candidates for the lowermost stage of the
Paleocene of China. From the viewpoint of charophytes, the outcrop
section of the Dangyang, Hubei Province (Central China) contains the
most continuous, abundant and diverse terrestrial biostratigraphic
records of the Cretaceous-Paleogene transition, in particular the
early Paleocene, known so far in the world. The biostratigraphic
records of ostracods in the transition are also continuous, rich, and
diverse. The Dangyang outcrop section is the only section known so far
in China that is a possible candidate for a continental stratotype of
the Cretaceous/Paleogene boundary in China and the section is the only
potential section identified to date for establishing the regional
lowermost stage of the Paleocene, Paleogene and Cenozoic in China or
stratotype section for the stage.