鲁砚的基本特征及形成的主要地质环境

在查阅、综合前人资料的基础上,通过野外观察、采样,结合偏光显微镜和热分析的实验数据,分析了几种常见鲁砚石的矿物成分及形成的地质环境。研究结果表明：沉积岩类的鲁砚石矿物成分几乎以泥晶方解石为主,另含少量陆源矿物。变质岩类鲁砚石矿物成分以绢云母、绿泥石为主要矿物,另含石英,电气石等矿物。鲁砚石主要产于鲁西地块,形成期以寒武纪居多,形成环境多滨、浅海相,河湖相。     

东海原甲藻核酸和蛋白对环境中氮磷浓度变化的响应

通过设定不同的氮(N)、磷(P)浓度一次性培养东海原甲藻,研究了该藻的生长状况及不同生长阶段单位细胞DNA,RNA及蛋白质含量的变化,结果表明,不同氮磷浓度对东海原甲藻的生长产生显著影响,最终生物量与初始的氮磷浓度呈正相关,不同培养组的最大生长率存在显著差异(P<0.05);DNA含量与培养液中氮浓度相关性极显著(P<0.01),但与磷浓度相关性不显著(P>0.05);RNA含量与氮磷浓度均呈极显著相关(P<0.01),而且在不同的生长阶段其含量也会发生变化,随着培养时间的延长,各培养组的RNA含量显著下降(P<0.05);RNA/DNA比值与氮磷浓度均显著相关(P<0.05),而且与生长率呈线性相关关系。培养液中氮浓度显著影响到东海原甲藻单位细胞总蛋白含量,磷缺乏也会使总蛋白含量显著降低。     

Tectonic regime switchover of Triassic Western Qinling Orogen: Constraints from LA-ICP-MS zircon U–Pb geochronology and Lu–Hf isotope of Dangchuan intrusive complex in Gansu,China

The Qinling Orogenic Belt, linking the Kunlun and Qilian Mountains to the west and continuing farther east to the Dabie Mountain, was assembled by the convergence and collision between the Greater South China and the North China blocks. The precise timing of the subduction and collision processes between these continental blocks and tectonic regime switchover is very equivocal. Zircon in-situ LA-ICP-MS U–Pb dating in this contribution indicates that the biotite monzogranite and monzogranite phases of the Dangchuan complex were crystallized at ca. 239.8 ± 2.3 Ma and 227.8 ± 1.2 Ma, respectively. The ca. 240 Ma biotite monzogranite displays ε_Hf(t) values ranging from −2.4 to +2.9, and corresponding T_DM2 of 1.72–1.94 Ga and T_DM1 of 0.77–0.88 Ga. The ca. 228 Ma monzogranite exhibits ε_Hf(t) values ranging from −4.3 to +1.9, and corresponding T_DM2 of 1.73–2.08 Ga and T_DM1 of 0.81–0.88 Ga. Lutetium–Hf isotopic composition indicates that the biotite monzogranite and monzogranite probably have the same parental magmas which were originated from hybrid sources of both reworking of Paleoproterozoic ancient crust and partial melting of the Neoproterozoic juvenile crust. The more negative ε_Hf(t) values of the monzogranite suggest more contribution of the ancient crust during the source contamination, or more possible crustal assimilation during their crystallization at ca. 228 Ma than precursor biotite monzogranite. Integrated with previous research and our detailed petrography, we propose that the Dangchuan complex underwent an episodic growth documenting the tectonic regime switchover from early Paleozoic to Triassic. The ca. 439 Ma inherited zircon recorded the persistent subduction of the oceanic crust, the ca. 240 Ma biotite monzogranite emplaced during the northward subduction of the Mianlue oceanic crust beneath the South Qinling block, and the ca. 228 Ma monzogranite emplaced during the syn-collisional process in a compressional setting.     

Provenance,tectonic setting and source of Archean metasedimentary rocks of the Browns Range Metamorphics,Tanami Region,Western Australia

This study combines U–Pb age and Lu–Hf isotope data for magmatic and detrital zircons, with whole-rock geochemistry of the Browns Range Metamorphics (BRM), Western Australia. The BRM are medium- to coarse-grained metasandstones that consist of angular to sub-rounded detrital quartz and feldspars with minor granitic lithic fragments. The sequence has undergone partial to extensive quartz–muscovite alteration and rare-earth-element mineralisation and has been intruded by mafic/ultramafic, syenitic and pegmatitic intrusive rock units. Uranium–Pb and Lu–Hf isotopic data on detrital zircons from the metasandstones and intruding granitic rocks yield a well-defined age of ca 3.2 to ca 3.0 Ga for all samples, with relatively radiogenic ?_Hf values (?_Hf = –1.7 to 5.1) indicating derivation from Mesoarchean granite basement of juvenile origin. This is consistent with geochemical and petrological data that support deposition from a granitic source in a continental rift basin setting. The timing of sediment deposition is constrained between the ca 3.0 Ga age of the source rocks and ca 2.5 Ga age of the granitic intrusive bodies that cross-cut the metasedimentary rocks. The ca 2.5 Ga zircons from the intrusive rocks have ?_Hf model ages of ca 3.4 to ca 3.1 Ga, which is consistent with formation via partial melting of the BRM, or the Mesoarchean granite basement. Zircons of the Gardiner Sandstone that unconformably overlies the BRM return detrital ages of ca 2.6 to ca 1.8 Ga with no trace of ca 3.1 Ga zircons, which discounts a significant contribution from the underlying BRM. The Mesoarchean age and isotopic signatures of the BRM zircons are shared by some zircon records from the Pine Creek Orogen, and the Pilbara, Yilgarn and Gawler cratons. Collectively, these records indicate that juvenile Mesoarchean crust is a more significant component of Australian cratons than is currently recognised. This work also further demonstrates that detrital minerals in Paleoproterozoic/Archean sedimentary rocks are archives to study the early crustal record of Earth.     

郯庐断裂带的演化及其对西太平洋板块运动的响应

首次从郯庐断裂带走滑糜棱岩中获得了白云母127.62±0.19Ma的⁴⁰Ar-³⁹Ar年龄,其与糜棱岩的全岩⁴⁰Ar^-39Ar年龄相吻合。这些年代学研究成果以及同走滑期岩浆活动,表明郯庐断裂带于早白垩世发生了大规模的左行平移。这一早白垩世构造—岩浆事件是伊泽纳崎板块突然发生高速、斜向俯冲的结果。晚白垩世早第三纪郯庐断裂带转变成巨型的伸展构造,普遍控制发育了断陷盆地。太平洋板块的高角度正向俯冲使中国东部出现软流圈上涌、岩石圈拆沉,从而造成了郯庐断裂带与整个中国东部卷入了强烈的伸展活动。晚第三纪初期起动的挤压活动,使郯庐断裂带上的断陷盆地同步抬升和闭合;断裂带的逆冲活动则断续延至今日,成为中国东部最大的近代地震活动带。郯庐断裂带晚第三纪以来的挤压活动是西太平洋弧后扩张的响应,而印度板块碰撞的构造挤出起着辅助作用。     

Lu-Hf同位素体系对若干基础地质问题的新制约(之一)--地球早期演化

Ｌｕ－Ｈｆ同位素方法已趋成熟,主要得益于其化学方法的极大改进和与之配套的高电离率质谱仪的使用。Ｌｕ－Ｈｆ同位素方法在地球的早期性质研究中表明,部分古太古代片麻岩Ｓｍ－Ｎｄ同位素体系所记录的早期地幔的“极度”亏损,实际是对其同位素体系热扰动的反映;关于大陆地壳的生长模式,石英岩锆石Ｌｕ－Ｈｆ同位素特征支持了幕式增生的观点     

萨拉乌苏河对芦河的袭夺及其历史地理意义

通过对地形、综合地层剖面年代、遥感影像、历史地图和历史文献等的分析,深入探讨了无定河上游历史时期河湖水系的情况。现今无定河上游,即萨拉乌苏河上游山区的水源地为袭夺无定河的另外一条支流芦河而来,且袭夺发生在北魏以后,明代之前。袭夺之前,东西向湖泽湿地的存在,影响了该区历史人类活动的空间分布,主要表现在人类聚落选址、交通通道等。本研究为重新认识《水经注》中有关奢延水的记载提供了新的地理参照,有助于重建无定河上游的历史景观,同时为理解黄土地区的历史河流演化提供了典型案例,具有重要意义。     

Bioavailability of dissolved organic phosphorus compounds to typical harmful dinoflagellate Prorocentrum donghaiense Lu

The bioavailability of dissolved organic phosphorus (DOP) compounds to harmful alga Prorocentrum donghaiense Lu and its alkaline phosphatase activity (APA) were studied. Results showed that P. donghaiense could utilize the test DOP compounds such as glucose-6-phosphate (G-6-P), adenosine triphosphate (ATP) and ribonucleic acid (RNA) to sustain its growth. Nutrition between the test DOP compounds and orthophosphate was comparable. P. donghaiense could utilize intracellular phosphorus to sustain growth under depletion of dissolved phosphorus. Variation of APA in different test DOP compounds was addressed; the controlling mechanism of APA in different DOP media was discussed.     

咸通松陵诗人群酬唱述论

晚唐咸通十一、十二年,以皮日休、陆龟蒙为代表的诗人群在松陵(今苏州)地区展开唱和活动,仅一年的时间创作诗歌698首.陆龟蒙将其结集为<松陵集>.该诗集主要以皮、陆二人的交往诗为主,间以诗人之间宴饮游戏之作.这一方面是诗人之间情谊的见证,另一方面也体现出唐末士人的好尚.该诗集的总体艺术成就并不高,但也不乏佳作,诸多咏物篇什体现出唐末咏物诗的特点.从群体之构成、诗集概貌、诗集中的咏物诗及诗人的末世心态等角度对该诗歌群体作一概述.通过对该群体及其作品的分析,透视处在时代交替之际士人的精神面貌.     

北宋路域耕地面积重建及时空特征分析

基于垦田和户口史料及耕地分布影响因子的分析,本文建立了北宋册载垦田数据的订正方法以及路域耕地分布倾向模型和分配模型,重建了北宋4个时点的路域耕地面积。结果表明：① 北宋开宝九年（976年）、至道三年（997年）、治平三年（1066年）和元丰元年（1078年）的耕地总量分别为468.27×10⁶今亩、495.53×10⁶今亩、697.65×10⁶今亩和731.94×10⁶今亩,百年间耕地面积增加了约2.64亿今亩;垦殖率从开宝九年（976年）的10.8%,增加至元丰元年（1078年）的16.9%,提高了约6个百分点;而人均耕地面积由15.7今亩降至8.4今亩。② 从空间变化特征看,东南地区是北宋土地垦殖发展最快的地区,土地垦殖率增加了约12.0%,北宋中期长江中下游平原局部地区垦殖率高达40%;其次是北方地区,土地垦殖率增加了5.2%,北宋中期黄淮海平原的土地垦殖率也超过了20%;西南地区农业发展相对落后,区域土地垦殖率仅增加1.2%,除成都府路外,各路垦殖率均低于6%。③ 从评估结果看,本文所构建的路域耕地分配模型具有一定的可行性,相对误差绝对值小于20%的路域占总路数的84.2%,结果能较好地反映北宋时期路域耕地面积的时空变化特征。