青藏高原东北缘多福屯陆内基性火山岩的40Ar/39Ar同位素定年和地球化学特征及其构造启示

目的探讨青藏高原东北缘多福屯地区钠质基性火山岩与青藏高原隆升及南北构造带活动之间的关系。方法运用地球化学和同位素Sr-Nd-Pb特征分析及全岩40Ar/39Ar同位素进行研究。结果全岩40Ar/39Ar年龄结果显示,多福屯钠质基性火山岩的形成时代为96.21 Ma±2.10 Ma,为晚白垩世(K2)早期。岩石元素-同位素地球化学特征表明,该套火山岩岩浆形成于部分熔融。火山岩表现为特征的DUPAL(高放射成因铅)异常,属似OIB性质的板内碱性—偏碱性玄武岩,源区具有DM与EMⅡ混合特点。结论多福屯火山岩相关的岩浆活动源于板块边界动力学引起的远程大陆陆内构造效应,即印度板块与欧亚大陆的早期碰撞(100～85 Ma),由于藏北板块的刚性特点,应力实现远程传递到高原东北缘,导致南北复合构造带在西秦岭西段发生构造扰动,诱发了软流圈地幔的部分熔融,形成多福屯火山岩原生岩浆。     

Climate change over southern Qinghai Plateau in the past 500 years recorded in <Emphasis Type="Italic">Sabina tibetica</Emphasis> tree rings

Two tree ring-width chronologies of Sabina tibetica were developed based on cores sampled in Qumalai and Zhiduo, southern Qinghai Plateau. The response function analysis showed that the chronologies were sensitive to temperature and precipitation from April to June in the plateau. Moisture index (MI) was defined, reconstructed and extended back to AD 1550. The cross-validation method was used to check the stability of the calibration equation, and the result indicated that the equation was stable. Six severe dry periods were found in this region in the past 453-year reconstruction, which were 1592 to 1610, 1649 to 1665, 1687 to 1697, 1740 to 1750, 1818 to 1829 and 1918 to 1933. Five severe wetting periods were 1669 to 1682, 1700 to 1709, 1800 to 1814, 1898 to 1909 and 1935 to 1950. Spectrum analysis indicated that there existed long-term cycles of 60.4 and 53.4 a, solar cycle of 11 a and short-term cycles of 8, 6 and 4 a in the reconstructed series.     

Sm-Nd isotopic geochronology of the Yinachang Fe-Cu-REE deposit at Wuding, Yunnan Province and its genetic significance

Sm-Nd isotope systematics of ores and fluorites places precise time constraints on REE mineralization of the Yinachang Fe-Cu-REE deposit in Yunnan Province which occur in the Proterozoic Kunyan group. The ore-related fluorites contain high abundant REE, and show a strong enrichment of LREE and a positive Eu anomaly, which is in marked contrast to post-ore fluorites that are HREE enriched. The Sm-Nd isochron ages of the ores and fluorites are 1539±40 Ma and 1617±100 Ma, respectively, and calculated εNd（t） are -4.6 and -3.2. Accurate age determinations of the mineralization demonstrate that the REE mineralization took place during early Mesoproterozoic. Together with other geological evidence from the ore deposit, the primary REE-bearing ore-forming fluids are suggested to have been derived from the Enriched Mantle, and the Yinachang Fe-Cu-REE ore deposit is of volcanic exhalation- hydrothermal sedimentary origin. This study also imply that the sudden large-scale REE mineralization in the Mesoproterozoic epoch may have been induced by alkaline-rich anorogenic magmatism which occurred at marginal rifts of the continent in the Mesoproterozoic.     

夏代仲康日食记载再读

仲康日食大约发生在公元前２０世纪。由于古代文献的真实性方面疑点颇多,记载信息不足,难于确定其发生年代,有时还引起对这个记载是不是日食记录的争议。目前,虽然根据其它可信文献趋同于认这它是日食记录,但确定其发生年代就有１１个不同的结论。     

Sm-Nd age of syncollisional mafic-ultramafic intrusions in the Dabie Mountains

A Sm_Nd age of (228±42) Ma with initial ε Nd =-16.4 for the Renjiawan pyroxenite intrusion in the North Dabie terrane is reported. This age with another Sm_Nd age of (230±44) Ma for the Zhujiapu pyroxenite in the same terrane documents that the pyroxenite in the North Dabie terrane are formed during continental subduction time of the Yangtze craton in the Triassic.     

先秦时期的舞蹈艺术

阐述了石器时代乐舞的形成,夏商周时期舞蹈的完善及春秋战国时期舞蹈的发展。指出,舞蹈艺术发展到春秋战国时期后,随着官学下移、私学兴起,更加贴近人们的生活,奠定了中国舞蹈艺术发展的现实主义基础。     

《史记》西周共和以后及东周年表初探

对《史记》“十二诸侯年表”、12“世家”和若干“本纪”的纪年与历日记载的分析表明：自西周共和以后及东周时期的纪年法,以次年王公纪年法为主流,当年王公纪年法为支流,并杂以若干非常规的王公纪年法;春秋时期共他诸侯国历法和鲁国历法大同小异,建正有建子、建丑之别;司马迁对这些纪年与历日的记述,是依据《春秋历谱谍》等可靠的史料作出的,其所构建的西周共和以后及东周年代,只有比例很小的失误,其整体是可靠的;西周共和元年是为公元前841年,可作为后计其后年代、前推其前年代的不可动摇的基本点。