Tuesday, August 06, 2013

Complete (?) Paleoclimate Record for Entire Cretaceous From Songliao Basin , China


Cretaceous paleogeography and paleoclimate and the setting of SKI borehole sites in Songliao Basin, northeast China

Authors:

1. Chengshan Wang (a, b)
2. Zhiqiang Feng (c)
3. Laiming Zhang (a, b)
4. Yongjian Huang (a, b)
5. Ke Cao (d)
6. Pujun Wang (e)
7, Bin Zhao (a, b)

Affiliations:

a. State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing 100083, China

b. School of the Earth Science and Resources, China University of Geosciences, Beijing 100083, China

c. Institute of Exploration and Development of Daqing Oil field Company Ltd, Daqing, 163712, China

d. The Key Laboratory of Marine Hydrocarbon Resources and Environment Geology, Qingdao institute of marine geology, Qingdao 266071, China

e. School of Earth Sciences; Jilin University; Changchun, 130061, China

Abstract:

As a paradigm of greenhouse climate in Earth's history, the Cretaceous provides significant rock records of global climate changes under conditions of greenhouse climate. The Songliao Basin, among the longest duration (85–90 m.y.) of continental sedimentary basins, provides an excellent opportunity to recover a nearly complete Cretaceous terrestrial sedimentary record. Extensive lake deposits, ten-kilometers deep and covering an area of 260,000 km2 of the Songliao Basin, provide unique, detailed records that can be tied to the global stratigraphic time scale, thereby improving our understanding of the continental paleoclimate and ecological system. The two coreholes at SKIs and SKIn sites were drilled into this basin and completed with a total length of 2485.89 m of recovered core that spanned the complete middle-to-Upper Cretaceous strata in the basin. The unique geological setting of long-term continuous subsidence within the largest Cretaceous landmass in the world — makes the Cretaceous Songliao Basin of northeastern China an ideal place to study Cretaceous climate change on the continent. This paper reviews the literature on the paleogeography and paleoclimate of the northern East Asia and the Songliao Basin during the Cretaceous. Based on the climatologically sensitive deposits, oxygen isotope studies, and paleontology, the climate during the Cretaceous in the Songliao Basin was temperate and humid with relatively abundant rainfall. During the period, significant changes – four cooling, three warming, and three semiarid events – are generally consistent with the oxygen isotope data from East Asia, and the four cooling events, in Berriasian–Valanginian, Aptian–Albian, early Santonian, and Campanian–Maastrichtian, may be related to potential glaciations in Cretaceous.

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