青海湖古气候与古环境

1 Introduction

1.1 Aim and scope

1.2 Previous investigations

1.2.1 1961-1962 expeditions to Lake Qinghai

1.2.2 Sino-Swiss expedition in 1985

1.2.3 1987 drill-core project

1.2.4 Post-1990 investigations

1.3 Paleoclimate study of China： a brief review

1.3.1 East Asian monsoon——the modem climate system

1.3.2 East Asian paleomonsoon

2 Geographic， Geological and Limnological Setting of Lake Qinghai

2.1 Geological setting

2.2 Geomorphological setting

2.3 Geographic setting

2.3.1 Climate

2.3.2 Vegetation

2.3.3 Rivers in the catchment

2.4 Limnological setting

2.4.1 Water chemistry

2.4.2 Physical characteristics

2.4.3 Biological characteristics

2.5 Peripheral lakes

2.5.1 Lake Erhai

2.5.2 Lake Gahai

2.5.3 Haiyan Bay

2.5.4 Sand-Island Lake

3 Investigation Methods

3.1 Introduction

3.2 Field investigation

3.2.1 Seismic profiling

3.2.2 Coring

3.3 Laboratory investigation

3.3.1 Radiometric dating

3.3.2 Magnetic susceptibility： core logging

3.3.3 Total organic carbon and total nitrogen， and C/N ratio

3.3.4 Macrofossil indicator

3.3.6 X-ray diffraction and scanning electron microscopy （SEM）

3.3.7 Oxygen and carbon stable isotopes

3.4 Notes on investigation methods

4 Seismic Investigation， Lithologie Study of Sediment Cores and Radiometrie Dating

4.1 Introduction

4.2 Sub-bottom profiles from the 3.5 kHz seismic investigations

4.3 Radiometric dating

4.3.1 Radiocarbon dating and sedimentation rates

4.3.2 pb dating and sediment accumulation rates

4.4 Lithologic units

4.4.1 Lithologic units of core Q14B

4.4.2 Lithologic units of core Q 16C

4.4.3 Core correlation and boundary description

5 Lake Levels and Climate Change During the Holoeene

5.1 Introduction

5.2 Results and interpretations

5.2.1 14C dated lithostratigraphy

5.2.2 TOC， TN and C/N ratio

5.2.3 TCC and carbonate mineral record

5.2.4 Fossil seeds from rooted aquatic plant

5.2.5 Ostracode shell stable-isotopic record

5.2.6 Pollen record

5.2.7 Magnetic susceptibility

5.3 Holocene lake levels and climate reconstruction

5.4 A correlation with proxy records from other studies

5.5 Holocene climate variability of East Asia

5.5.1 Early Holocene climate regime

5.5.2 Mid-Holocene climate and Holocene Optimum

5.5.3 Late Holocene climate

5.5.4 Climate forcing and feedbacks during the Holocene

5.6 Summary and conclusions

6 Abrupt Changes in Climatic Conditions Across the Lateglacial/Holoeene Transition

on the NE Qinghai-Tibet Plateau

6.1 Introduction

6.2 Results from a multi-proxy investigation on cores Q14B and Q 16C

6.2.1 Distinct lithostratigraphic units

6.2.2 Paleobotanic evidence

6.2.3 Core logs of magnetic susceptibility

6.2.4 Carbonate content and mineralogical record

6.2.5 Oxygen stable-isotopic record

6.2.6 Total nitrogen content

6.3 Reconstruction of lake levels and limnological conditions

6.4 Abrupt shifts in hydro-climatic conditions

6.5 Correlation with other paleoenvironmental records in China

6.6 Conclusions

7 Paleoenvironmental Signatures from Carbonate Minerals and Stable Isotopic Ratios from Lake Qinghai

7.1 Introduction

7.2 Modern carbonate environments

7.3 Carbonate minerals in the sediment cores

7.4 Lake Qinghai dolomite and inferred paleoenvironment

7.4.1 Lithology， mineralogy， organic carbon and nitrogen， and isotopic composition

7.4.2 Geochemical and paleoenvironmental conditions for the dolomite formation

7.5 Brine evolution deduced from the carbonate mineral record

7.5.1 Mg/Ca ratio

7.5.2 Carbonate production and salinity

7.6 Stable isotopic ratios and their covariance

7.6.1 Isotopic covariance

7.6.2 Isotope results from Lake Qinghai

7.6.3 Discussion

7.7 Summary and conclusions

8 Paleoenvironment and Paleoclimate Conditions During the Marine Isotopic Stage 3 and the Last Glacial Maximum

8.1 Introduction

8.2 Results and interpretations

8.2.1 Seismic reflection Profile No. 1

8.2.2 Sediment core Q87

8.2.3 AMS 14C dating and analytical measurements of Q87

8.2.4 Carbonate mineral record

8.2.5 Total organic carbon， total nitrogen and C/N ratio

8.3 Climatic conditions at the MIS 3 and the LGM

8.4 Correlation with other proxy records in the region

8.4.1 The Marine Isotope Stage 3 （MIS 3）

8.4.2 The Last Glacial Maximum （LGM）

8.4.3 Correlation with glaciation records

8.5 Summary and conclusions

References

Acknowledgments

《青海湖古气候与古环境（英文版）》以青藏高原东北部六万.0以来的气候与环境演变为主要研究内容，以多学科方法研究获得了青海湖岩芯多项环境指标，并以此为依据，分析和论证了青海湖MIS3、MIS2、末次冰期向全新世过渡时期，以及全新世等各时段的水位与气候变化，及其与东亚季风演变的关联。