Palaeochannels are deposits of unconsolidated sediments or semi-consolidated sedimentary rocks depos- ited in ancient, currently inactive river and stream channel systems. It is distinct from the overbank deposits of ...Palaeochannels are deposits of unconsolidated sediments or semi-consolidated sedimentary rocks depos- ited in ancient, currently inactive river and stream channel systems. It is distinct from the overbank deposits of currently active river channels, including ephemeral water courses which do not regularly flow. We have introduced a spectral characteristics-based palaeochannel information extraction model from SPOT-5 imagery with special time phase, which has been built by virtue of an analysis of remote sensing mechanism and spectral characteristics of the palaeochannel, combined with its distinction from the spatial distribution and spectral features of currently active river channels, also with the establishment of remote sensing judging features of the palaeochannel in remote sensing image. This model follows the process of supervised classification → farmland masking and primary component analysis→ underground palaeochan- nel information extraction → information combination→ palaeochannel system image. The Zhegao River Valley in the east of Chaohu Lake was selected as a study area, and SPOT-5 imagery was used as a source of data. The result was satisfactory when this method has been successfully applied to extract the palaeochannel informa- tion, which can provide good reference for regional remote sensing archeology and neotectonic research. However, the applicability of this method needs to be tested further in other areas as the spatial characteristics and spectral response of palaeochannel might be different.展开更多
The palaeochannel evolution in the study region is divided into four stages by such methods as 14C dating. Sea water intrusion through palaeochannels has been studied as a focal point. Palaeochannels are the main pass...The palaeochannel evolution in the study region is divided into four stages by such methods as 14C dating. Sea water intrusion through palaeochannels has been studied as a focal point. Palaeochannels are the main passageways through which the sea water intrudes at a higher speed, through many means and in a changeable dynamic state.展开更多
The palaeochannels in the studied region are divided into four stages by such methods as 14C dating. Marine (saltwater) transgression in the palaeochannels has been studied as a focal point. Palaeochannels are the mai...The palaeochannels in the studied region are divided into four stages by such methods as 14C dating. Marine (saltwater) transgression in the palaeochannels has been studied as a focal point. Palaeochannels are the main passageway through which the seawater (saltwater) transgresses. The seawater (saltwater) transgresses at a high speed, by many means and in a changeable dynamic state.展开更多
Palaeorunoff regimes were reconstructed using the equations relating annual runoff to climatic parameters and palaeoclimatic information acquired mainly by pollen analysis and peat investigation for southem Hebei (114...Palaeorunoff regimes were reconstructed using the equations relating annual runoff to climatic parameters and palaeoclimatic information acquired mainly by pollen analysis and peat investigation for southem Hebei (114~117°E, 36~38°N) during the last 70 000 years. With the morphological data of palaeochannels preserved in the same region, discharge estimates were calculated with the equations relating discharge to morphological parameters of channel for the palaeorivers acting during the last 25 000 years. For the last 25 000 years, the reconstructed palaeorunoff regimes were compared to the corresponding palaeodischarge ones. This comparison indicates the same trend of hydrological changes occurring in southern Hebei during the last 25 000 years. During 8 000~25 000 or 7 500~25 000 a B.P, the quantity of surface water was rather small and probably just 46 or 60 percent of the one for the interval of 3 000~8 000 or 2 500~7 500 a B.P The surface water was the least during 0~3 000 or 0~2 500 a B.P, being 34 or 33 percent of the one occurring during 3 000~8 000 or 2 500~7 500 a B.P The maximum surface water occurred during 3 000~8 000 or 2 500~7 500 a B.P. when the runoff ranged 147.6~398.0 mm and discharge 210-324 m3/s.展开更多
基金Acknowledgements The research work was supported by the National Natural Science Foundation of China （No. 40971115）, Scientific Research Foundation of Graduate School of N anjing University （No. 2011CL 11 ）, the National Science and Technology Support Program of China （No. 2010BAK67B02）, University Doctoral Foundation of China （No. 20090091110036）, Open Foundation of the State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, CAS （No. SKLLQG0817）, and Major Program of Natural Science Research at University of Anhui Province （No. ZD200908）.
文摘Palaeochannels are deposits of unconsolidated sediments or semi-consolidated sedimentary rocks depos- ited in ancient, currently inactive river and stream channel systems. It is distinct from the overbank deposits of currently active river channels, including ephemeral water courses which do not regularly flow. We have introduced a spectral characteristics-based palaeochannel information extraction model from SPOT-5 imagery with special time phase, which has been built by virtue of an analysis of remote sensing mechanism and spectral characteristics of the palaeochannel, combined with its distinction from the spatial distribution and spectral features of currently active river channels, also with the establishment of remote sensing judging features of the palaeochannel in remote sensing image. This model follows the process of supervised classification → farmland masking and primary component analysis→ underground palaeochan- nel information extraction → information combination→ palaeochannel system image. The Zhegao River Valley in the east of Chaohu Lake was selected as a study area, and SPOT-5 imagery was used as a source of data. The result was satisfactory when this method has been successfully applied to extract the palaeochannel informa- tion, which can provide good reference for regional remote sensing archeology and neotectonic research. However, the applicability of this method needs to be tested further in other areas as the spatial characteristics and spectral response of palaeochannel might be different.
基金This research was supported by the Natural Science Foundation of Shandong Province of China under contract No.Y2000E03.
文摘The palaeochannel evolution in the study region is divided into four stages by such methods as 14C dating. Sea water intrusion through palaeochannels has been studied as a focal point. Palaeochannels are the main passageways through which the sea water intrudes at a higher speed, through many means and in a changeable dynamic state.
文摘The palaeochannels in the studied region are divided into four stages by such methods as 14C dating. Marine (saltwater) transgression in the palaeochannels has been studied as a focal point. Palaeochannels are the main passageway through which the seawater (saltwater) transgresses. The seawater (saltwater) transgresses at a high speed, by many means and in a changeable dynamic state.
文摘Palaeorunoff regimes were reconstructed using the equations relating annual runoff to climatic parameters and palaeoclimatic information acquired mainly by pollen analysis and peat investigation for southem Hebei (114~117°E, 36~38°N) during the last 70 000 years. With the morphological data of palaeochannels preserved in the same region, discharge estimates were calculated with the equations relating discharge to morphological parameters of channel for the palaeorivers acting during the last 25 000 years. For the last 25 000 years, the reconstructed palaeorunoff regimes were compared to the corresponding palaeodischarge ones. This comparison indicates the same trend of hydrological changes occurring in southern Hebei during the last 25 000 years. During 8 000~25 000 or 7 500~25 000 a B.P, the quantity of surface water was rather small and probably just 46 or 60 percent of the one for the interval of 3 000~8 000 or 2 500~7 500 a B.P The surface water was the least during 0~3 000 or 0~2 500 a B.P, being 34 or 33 percent of the one occurring during 3 000~8 000 or 2 500~7 500 a B.P The maximum surface water occurred during 3 000~8 000 or 2 500~7 500 a B.P. when the runoff ranged 147.6~398.0 mm and discharge 210-324 m3/s.
