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Table 2 Pollen data of the 20 representative samples from the Tianzhu borehole.

From: Environmental magnetic record of the fluvial sediments from the Tianzhu borehole in Beijing for the last 800 ka

Number

Depth (m)

Lithology

k (SI)

Pollen of Trees

Chenopodiaceae (%)

A/C ratioa

Hydrophytes & Cyperaceae (%)

Concentration (grains/g)

Climate indicatorb

    

Mesophilous species

Cold-resistant species

     

P1

1.86

Silt

8.6 × 10−4

Quercus, Corylus, Ulmus, Carpinus

Pinus, Betula, Salix

6.67

2.75

1.67

480

Warm, humid

P2

4.88

Silt

3.9 × 10−4

Ulmus

Pinus, Picea, Salix

38

0.02

2.00

972

Cold, dry

P3

14.39

Clay

2.9 × 10−4

Ulmus

Pinus, Betula

5.0

1

0.00

3600

Cold

P4

27.09

Sand

9.7 × 10−4

Corylus, Ulmus

Salix

13.33

0.3

2.67

666

Warm

P5

42.93

Clay

1.9 × 10−4

Corylus, Ulmus

Betula

11.75

1.45

16.33

48000

Warm, humid

P6

58.59

Sand

2.31 × 10−3

Quercus, Corylus, Ulmus, Tilia

Pinus, Betula, Salix

6.0

2.78

4.33

360

Warm, humid

P7

63.49

Sandy silt

4.3 × 10−4

Ulmus, Carpinus

Pinus, Betula

33.0

0.17

0.67

800

dry

P8

72.2

Sandy silt

7.5 × 10−4

Ulmus, Tilia

Pinus, Salix

2.67

2.25

0.00

600

Warm, humid

P9

77.91

Silty clay

1.2 × 10−4

Quercus, Ulmus, Carpinus

Pinus, Picea, Abies, Betula

7.33

1.77

1.00

82

Cold, dry

P10

93.61

Sandy silt

1.15 × 10−2

Pinus, Picea, Betula, Salix

25.0

0.05

0.67

1333

Cold, dry

P11

96.36

Silty clay

3.0 × 10−4

Ulmus

Pinus, Picea, Betula

30.0

0.01

2.00

7200

Cold, dry

P12

108.66

Silt

1.32 × 10−3

Corylus

Salix

12.33

0.54

13.33

36000

Warm, humid

P13

117.14

Silty clay

3.0 × 10−4

Ulmus

Pinus, Betula, Salix

6.33

0.84

2.33

36000

Cold

P14

124.52

Sand

1.02 × 10−2

Corylus, Ulmus, Juglans

Pinus, Betula, Salix

3.0

1.89

0.00

61

Warm

P15

134.27

Clay silt

2.0 × 10−4

Corylus, Ulmus

Salix

38.0

0.07

0.00

18000

dry

P16

143.42

Sand

2.55 × 10−3

Ulmus, Acer

Pinus, Betula, Salix

6.33

1.42

0.67

180

Warm

P17

152.3

Silty clay

1.2 × 10−4

Pinus

1.0

4.67

0.33

307

Cool, humid

P18

160.89

Sandy silt

2.19 × 10−3

Carpinus

Pinus, Picea, Betula

5.0

1.6

0.33

124

Cold

P19

167.46

Silty clay

1.5 × 10−4

Pinus

10.0

1

0.00

400

Cold

P20

176.18

Silt

8.0 × 10−4

Pinus, Salix

27.5

0.11

4.50

48000

Cold, dry

  1. a A/C ratio refers to the pollen ratio of Artemisia to Chenopodiaceae.
  2. b On the basis of the percentages of Chenopodiaceae, A/C ratio, the species of Trees, the percentages of Hydrophyte and Cyperaceae, and pollen concentration, we can know that cold or dry climate indicator pollen are found in strata with low values of magnetic susceptibility, while warm or humid climate indicator pollen are mostly found in beds with high magnetic susceptibility values.