Radiocarbon Dating For Geological Disaster Events

Nowadays more than 20 kinds of dating methods have been applied to determine Quaternary strata and geological events. Among them radiocarbon dating has been widely accepted for numerical dating the late Quaternary and particularly Holocene geological events. However, high resolution of decades or hundreds years for geological samples and reliable ages of geologic strata chronology are an urgent problem to be resolved which challenges for further studies of geological disaster events. Therefore it is very vital to improve the precision and accuracy of numerical dating methods. This thesis presents a series of experimental results, focusing on two important aspects of radiocarbon dating.1. The performance test of Quantulus-1220 liquid scintillation counter The Chinese Sucrose standard, synthetical benzene and the known ages of dendro-dated tree ring sample were used to assess the performance of Quantulua-1220. The results indicate that:(1) The background is below 0.5 cpm and the fluctuation does not exceed 4‰in the measuring surrounding, thus it is inferred that the maximum datable age for this instrument is expected to reach about 48 Ka BP;(2) The quench calibration curve was established by determining the relative efficiency variety of Chinese Suguar with the quench parameter SQP (E). The experience formula is: C=0.002630040912*X+10.99101753. The quench SQP (E) parameter of 261 radiocarbon samples varies from 700 to 758 in this study. The average value is 735.5 with standard deviation of 9.2. The maximum age error caused by quenching factor is less than 80 years, as calculated from the quench formula;(3) A set of growth rings, up to 45 rings, 60 g weigh, 6.5 cm long, were used to test the reliability of the dating procedure in our lab. This ring sample was dated to be 5458±54 a BP and the calibrated age is 4355 BC (68.2%) 4255 BC, converting in OxCasl 3.10 program. This dating result agrees well with the dendro-dated age of 4249~4294 BC. This proves that the sample pretreatments and its radiocarbon dating results in the laboratory are reliable.2. Radiocarbon dating of different components isolated from paleosol Radiocarbon dating is usually used to estimate the date of paleoearthquakes because the paleosol is ubiquitous in trenches. Five paleosol samples and a piece of pottery were collected from a trench wall at the Shangdalai village, near Tumotezuo county, located in the southern margin fault of the Daqing Mountain, Inner Mongolia. They were dated by radiocarbon dating and thermoluminensence dating, respectively. The...