Data for: Pollen records of the Little Ice Age humidity flip in the middle Yangtze River catchment

Published: 19 June 2018| Version 2 | DOI: 10.17632/78t2yz2xrf.2
Contributors:
Chunmei Ma,
Yulian Jia,
Lin Zhao,
Anning Cui,
Lingyu Tang

Description

Grain size was determined using a Malvern Mastersizer 2000 type particle size analyzer, guided by Lu and An (1998). The grain-size distribution was then transformed into different end-members for better characterization of the depositional environments (Weltje and Prins, 2003).Assessment of the detrital grain-size distributions yielded an optimal model with four end-members (EMs) explaining 99.8% of the original data variance. The mean total R2 between the original and modeled data is generally >0.9. EM1 and EM2 explain 58.3% and 27.1% of data variance, respectively. The grain-size distribution reveals diverse kurtosis, which can reflect different soil conservation and vegetation conditions when there is no flowing water. EM1 has a narrow range from 10µm to 100µm with a peak at ~18µm; EM2 has a broad range from 10µm to 1000µm with a peak at ~129µm; EM3 has a range greater than 100µm with a peak at almost 1000µm, and EM4 has a complex kurtosis (Fig. 3A). The results of the grain-size temporal distribution suggest that EM1 and EM2 are the main components and together account for almost 90% of the total, while EM3 and EM4 are persistently low. The median grain size shows high fluctuations and varies from 0 to 150μm.

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