一批考古,地质样品的^14C年龄数据报道

近年,应用~(14)C年龄测定法测定了一批广东、福建、海南等省的考古及地质样品的年龄,涉及多种类型的样品,对人类考古学、第四纪地质学及地貌学有一定的参考价值。     

山东蒙阴金伯利岩的古地磁初探

本文主要通过磁化率各向异性即磁性组构的研究,证明山东蒙阴金伯利岩矿床是属于侵入成因,并阐述了用磁性组构取代岩石学组构测量是地质学发展的一种新趋势。根据视极移曲线及同位素测定岩石年龄的方法,确定岩体的形成时代为加里东期岩浆活动,以此对燕山期岩浆活动的结论提出质疑。     

山东昌乐与碱性玄武岩有关刚玉巨晶中锆石包裹体的发现及其意义

山东昌乐蓝宝石矿是我国最大的与新生代碱性玄武岩有关的蓝宝石矿床,但对其成因仍有不同的认识[1,2].本文根据昌乐刚玉巨晶中发现的锆石包裹体,探讨刚玉巨晶的成因.1　地质背景与山东昌乐蓝宝石矿床有关的碱性玄武岩的产出主要受沂沐断裂(郯庐断裂山东段)及其次级断裂——...     

铁球磨介硅酸锆超细粉碎的工艺研究

比较搅拌球磨机的主要磨介的特点，介绍用铁球麻介生产具有国际同类质量水平的硅酸锆超细粉的生产实践，并就生产中的几个主要环节进行了探讨。     

14C dating of moss peat banks in Fildes Peninsula, Antarctica

Based on the radiocarbon data of the moss peat banks in Fildes Peninsula, Antarctica, it was calculated that the mean rates of peat accumulation in the upper layer and the lower layer are 0.195 and 0.069 4 mm · a^™1 respectively. Based on the radiocarbon date (3 265 ± 120 aBP) and the mean rate of peat accumulation in the lower peat layer, it was calculated that the age of the coast terrace on which the moss peat bank occurs is earlier than 4 300 aBP. During the past 4 300 years the coast terrace has risen about 18 m without apparently being destroyed, and the age of the glacier retreating process in this area is also earlier than 4 300 aBP.     

Precise timing of lacustrine gypsum in Luobubo, Xinjiang using the thermal ionization mass spectrometry U-series method

Dating techniques including gypsum dissolution in water, iron hydroxide co-precipitation with uranium and thorium and mass spectrometric determination have been investigated in this note. The ages of the gypsum samples in a CK core from Luobubo lacustrine sediments are in the range of (12.85±0.21) kaBP (4 m distance from the top core) to (153.2±7.2) kaBP (49 m distance from the top core) with the relative errors of ±1.6%–±4.7%. It indicates that the sedimental environment of the CK core was situated in the middle-late Pleistocene and Holocene periods, corresponding to 1–6 stages of oxygen isotopes in the abyssal sediments and included much information from last interglacial to Holocene warm periods.     

Fine grain IRSL and GLSL dating of late Quaternary sediments from North China

A possible approach to assess the fine grain OSL dating is discussed through comparison of equivalent dose (D_E) values and ages obtained by IRSL and GLSL of fine grains for 31 sediment samples from North China. The IRSL and GLSL were measured with the same aliquots for each sample, i.e. shine-down was by 100 s of IRSL (880 nm) followed by 100 s of GLSL (514 nm) on the same discs. The D_E values and ages found by IRSL are in good agreement with those by GLSL within 1—2σ for 80% samples, especially for aeolian loess samples. Considering that IRSL from feldspar differs obviously from GLSL dominated from quartz in dose response, thermal stability and optical bleaching characteristic, the agreement between the D_E values may be taken as evidence that the two clocks of IRSL and GLSL had been well reset during deposition. The consistent ages of IRSL and GLSL, in turn, may be referred to an indicator to evaluate the fine grain OSL dating of sediments.     

火山岩样品的预处理及其对K-Ar年龄值的矫正

K-Ar和Ar-Ar法是中、新生代火山岩最有效的测年方法之一,合适的粒度和有效的预处理程序对于提高年龄资料的质量至关重要。样品粒度选用60～80目粒级（0.28～0.18mm）既能保证样品的均匀性,又可以有效去除大气氩的污染。新鲜火山岩需要用稀硝酸浸泡,以去除可能的碳酸盐的影响;轻微蚀变的火山岩则须用6%氢氟酸浸泡5 min,对年龄值的矫正可达20%。用电磁选的方法可以在很大程度上剔除捕虏晶的影响,对年龄值的矫正可达5%～10%。