Despite numerous research efforts in recent decades, the precise time of this event has remained a puzzle until now. New evidence in helping settle this issue is provided by Prof. Deng Shenghui and his colleagues in their paper newly published in Science in China (2009, vol.52).
Geological studies have demonstrated that during the early Paleozoic, an interval from 450-300 million year ago, the Siberian paleo-land was thousands kilometers away from the North China paleo-land, which is very different from their present situation. An immense ocean of thousands kilometers wide, namely the Paleoasian Ocean, separated these two paleo-lands. During the Carboniferous and Early Permian (about 360-270 million year ago), the North China paleo-land was located near the equator, where subtropic-tropic type of flora grew, named as "the Cathaysia Flora". In contrast, the Siberian paleo-land was located at high latitude, where temperate flora was distributed, known as "the Angara Flora". These two types of floras are very distinctive and do not mix with each other because of the geological barrier and their separate niches in different climatic zones.
Prof. Deng and his collaborators concluded that the time of the Paleoasian Ocean's disappearance is the end of the Permian, about 251 million years ago, based on their study of land plant fossils. Several years ago, Deng and his research group found many plant fossils from the rocks that were formed in the Late Permian during their stratigraphical and paleontological investigation in Heilongjiang, Northeast China. These fossils could be divided into two types after detailed identifications. One belongs to Angara Flora and the other to Cathaysia Flora. So, these plant fossils represent a mixed flora. The mixed flora implies that the Angara type plants lived together with some Cathaysia type plants at this location in the Late Permian. This means that the Paleoasian Ocean, once a barrier of plant immigration, must have disappeared in the Late Permian, and those plants grew previously in North China paleo-land now immigrated to the Siberian paleo-land. Therefore, Deng and his colleagues suggested that the Paleoasian Ocean finally closed at the end of the Late Permian, about 251 million years ago.
Prof. Deng is a paleontologist in the Research Institute of Petroleum Exploration and Development, PetroChina, which is the largest national oil corporation in China. In order to explore more oil and gas resources, many basic geological problems should be solved first, such as the forming age of the oil and gas-bearing rocks, the paleogeography, paleoclimate, and paleoecology etc. Fossils, fossilized bodies and traces of ancient animals and plants, play an extremely important role in study of these basic geological problems. Prof. Deng and his paleontological group focus on the researches of various fossils.
The study was supported first by the Key Research Project of PetroChina and then by the National Program on Key Basic Research Project (Grant No: 2006CB701400).
Reference: Deng S H, Wan C B, Yang J G. 2009. Discovery of a Late Permian Angara-Cathaysia mixed flora from Acheng of Heilongjiang, China, with discussions on the closure of the Paleoasian Ocean. Science in China, Series DFEarth Science, vol. 52, no.11: 1746-1755.
Shenghui Deng | EurekAlert!
Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland
Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.
Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
24.03.2017 | Materials Sciences
24.03.2017 | Physics and Astronomy
24.03.2017 | Physics and Astronomy