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

Shi, Linfeng; Yang, Zhenyu; Zheng, Liandi; Jia, Sanman; Tong, Yabo; Zhang, Shuqin; Xu, Daoyi; Guo, Gaoxuan

doi:10.5047/eps.2010.07.015

Earth, Planets and Space

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 ratio^a	Hydrophytes & Cyperaceae (%)	Concentration (grains/g)	Climate indicator^b
				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

^a A/C ratio refers to the pollen ratio of Artemisia to Chenopodiaceae.
^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.

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