Instrumental records indicate a close relationship between the El Niño‐Southern Oscillation and the East Asian winter monsoon (EAWM) on interannual to decadal time scales. However, few studies have examined possible links between them on centennial/millennial time scales. In Northeast China, modern observations show that the immigration of temperate forest trees such as Pinus (pine) and Quercus (oak) into cold temperate boreal forest is sensitive to changes in winter temperature. Here we present a continuous high‐resolution pollen record from Lake Moon in the central part of the Great Khingan Mountain Range, Northeast China. The record reveals increasing contents of Pinus and Quercus pollen after ~6.0 ka cal. BP, which may indicate a gradual weakening of the EAWM. It is broadly coupled with an increasing El Niño frequency since the middle Holocene, and we observe a statistically significant correlation between the percentages of Pinus and Quercus and a time series of El Niño events. On the centennial to millennial time scale, the results of wavelet analysis and band‐pass filtering show that the occurrence and development of El Niño have also promoted a weaker EAWM after ~6.0 ka cal. BP, which is inversely correlated with the variation of the ca. 500‐year cycle originated from changes in solar output. These results imply that the climate transition in the mid‐Holocene is caused by the change of variations in solar activity and amplified by ocean circulation El Niño‐Southern Oscillation to influence the East Asian Monsoon system, especially the EAWM, and finally change the vegetation in Great Khingan Mountain Range.

The Great Khingan Mountain range, Northeast China, is located on the northern limit of modern East Asian Summer Monsoon (EASM) and thus highly sensitive to the extension of the EASM from glacial to interglacial modes. Here, we present a high-resolution pollen record covering the last glacial maximum and the early Holocene from a closed crater Lake Moon to reconstruct vegetation history during the glacial-interglacial transition and thus register the evolution of the EASM during the last deglaciation. The vegetation history has gone through distinct changes from subalpine meadow in the last glacial maximum to dry steppe dominated by Artemisia from 20.3 to 17.4 ka BP, subalpine meadow dominated by Cyperaceae and Artemisia between 17.4 and 14.4 ka BP, and forest steppe dominated by Betula and Artemisia after 14.4 ka BP. The pollen-based temperature index demonstrates a gradual warming trend started at around 20.3 ka BP with interruptions of several brief events. Two cold conditions occurred around at 17.2–16.6 ka BP and 12.8–11.8 ka BP, temporally correlating to the Henrich 1 and the Younger Dryas events respectively, 1and abrupt warming events occurred around at 14.4 ka BP and 11.8 ka BP, probably relevant to the beginning of the Bølling-Allerød stages and the Holocene. The pollen-based moisture proxy shows distinct drought condition during the last glacial maximum (20.3–18.0 ka BP) and the Younger Dryas. The climate history based on pollen record of Lake Moon suggests that the regional temperature variability was coherent with the classical climate in the North Atlantic, implying the dominance of the high latitude processes on the EASM evolution from the Last Glacial Maximum (LGM) to early Holocene. The local humidity variability was influenced by the EASM limitedly before the Bølling-Allerød warming, which is mainly controlled by the summer rainfall due to the EASM front covering the Northeast China after that.

Varve counts with AMS ¹⁴C, ¹³⁷Cs and ²¹⁰Pb dating of sediments (0–900 cm) from Erlongwan Maar Lake, NE China were used to establish a high-resolution chronology series for the late Quaternary. Dry density, total organic carbon (TOC) content, total nitrogen (TN) content, TOC/TN ratios and stable organic carbon isotope (δ ¹³C_org) ratios were continuously analyzed on this sediment profile. On the basis of lithological characters, sporo-pollen assemblages and geochemical analyses, we identified 6 climate stages within the last 14 ka BP. The time before the Holocene (14-11.4 ka BP) represents a higher-order oscillation climatic transitional period (I). The entire Holocene climate development (from 11.4 ka BP to present) exhibited an increasing temperature trend, although there were cold and warm alternations (II–VI). The periods included were: II (11.4-9.05 ka BP) warm-wet stage, III (9.05-7.4 ka BP) cold and warm fluctuation stage, IV (7.4-4.2 ka BP) smoothly warming climate stage, V (4.2-1.67 ka BP) climate optimum stage, and VI (from 1.67 ka BP to present) cool and drier stage. Each climate stage began with a warming event and ended with an abrupt cooling event. This climate change cycle had unequal time spaces that were progressively shorter over time. Several abrupt climate shifts occurred at about 9.4-9.05, 8.5-8.2, 7.8-7.4, 4.6-4.2, 3.7-3.25, 2-1.67 and 0.3-0.03 ka BP. Thus, it can be seen that the climate has been warming since 1920 AD, which indicates a new climate stage.

In this study, four basalt rocks were selected to produce continuous fibers, the chemical composition of basalt rocks and the corresponding fibers were compared using the XRF, the results reveal that the content of the chemical component present in the basalt fibers is consistent with basalt rocks. The mass attenuation coefficient of different fibers was analyzed using the XCOM program, the results indicate that when the incident electron energy is 0.01~0.1 MeV, fiber mass attenuation coefficient is found to be positively correlated with the content of Wt (Fe₂O₃ + MnO + TiO₂ + CaO + K₂O). The structure and properties of the fibers irradiated by different absorption doses of gamma rays were studied using the SEM, EDX and FTIR, the results indicate that irradiation produces no effect on the basalt fiber structure, surface morphology, and contents of the surface elements, the mass loss rate of the fiber was much less than 1%, fiber tensile strength and elastic modulus increased 4.7–7.5% and 3.9–9.1%, respectively, but the elongation at break of fiber decreased 4.18–10.97%. Two selected basalt fiber cloths of thickness 0.12 and 0.28 mm were irradiated with gamma rays of energies of 100 and 120 keV to examine the shielding property of basalt fibers against the gamma rays, when the energy was 100 keV, the shielding ratios of the fiber cloths were 18.9% and 22.5%, respectively, but when the energy was 120 keV, the shielding ratios of the fiber cloths decreased significantly and were at 8.7% and 10.4%, respectively. When the irradiated electron energy is 100 keV, the shielding ratio for basalt fiber cloths measuring 0.12 and 0.28 mm can reach up to 38.9% and 46.3% of that of the 0.5-mm lead plate, respectively.