粤北长塘盆地晚白垩世早期流纹岩的成因:地球化学和Sr-Nd-Pb-Hf-O同位素制约

长塘流纹岩为"大量流纹岩-少量玄武岩"构成的不对称双峰式火山岩组合的酸性端元,前人对年代学研究认为是目前华南识别的燕山期最年轻的流纹岩(SHRIMP年龄96.8 Ma),但在岩石地球化学特征及成因方面尚未深入研究。本文通过全岩主微量元素、Sr-Nd-Pb-O和锆石Hf同位素研究得到:流纹岩为亚碱性弱过铝质岩石,稀土元素富集,轻重稀土分馏明显,Eu负异常;具有较小的(~(87)Sr/~(86)Sr)_i、较高的εNd(t)和较低的(~(206)Pb/~(204)Pb)_i、(~(207)Pb/~(204)Pb)_i、(~(208)Pb/~(204)Pb)_i值;锆石的εHf(t)值较高且Hf模式年龄和全岩基本一致,均显示为新生下地壳岩浆;全岩的δ18O值较高。结合区域地质资料,本文认为长塘流纹岩是在晚白垩世早期拉张环境下,源于EMⅡ富集地幔的岩浆混染少量下地壳物质形成新元古代新生下地壳,发生熔融产生的岩浆在上升过程中经历结晶分异演化后喷出地表的产物。晚白垩世早期流纹岩成因对华南陆壳拉张减薄到正常厚度时间节点提供了证据。     

年轻石笋平均沉积速率的确定——多方法探讨

石笋凭借其准确的年代学和对洞穴外界环境的敏感响应,已经成为第四纪研究的重要力量。亚洲季风区轨道-千年尺度石笋δ18O指示亚洲季风强弱的变化,但是在更短的时间尺度上,石笋δ18O则可能受到其他因素的影响,因此近现代、能与器测记录进行对比的石笋记录研究是衔接现代气候与古气候的关键环节。而这关键环节中的关键问题就是确定石笋的沉积年代。寻找一种适合于无生长纹层、低U含量石笋样品的年代方法对于解决石笋沉积年代有着重要的推动作用。本研究选择广西桂林茅茅头大岩一正在生长的年轻石笋。由于低U含量、高232 Th含量,U系-230 Th定年不成功。利用210Pb定年计算出平均沉积速率为1.96±0.23mm/a,但由于多层晶间孔隙的存在,计算结果偏小。由于石笋中14 C基本为核爆产生,AMS 14 C测试结果计算石笋平均沉积速率为2.10mm/a,但由于未测量到核爆前14 C数据,其值可能仍偏小。由于前人研究指出桂林地区石笋记录能记录夏季风降水,结合桂林多年降水数据,综合计算出该石笋平均沉积速率为2.44mm/a,生长时限为2009—1968年。平均沉积速率和沉积时代的确定,为后续的石笋现代气候研究,进而与古气候衔接提供了重要的研究基础。     

New radiocarbon age constraints for the 120 km-long Toomba flow,north Queensland,Australia

The Toomba flow is the youngest flow of the Nulla volcanic province, located in north Queensland. This 120?km-long flow has yielded a published ⁴⁰Ar/³⁹Ar age of 21,000?±?3000 years. In contrast, seven published conventional radiocarbon (¹⁴C) analyses of carbon-bearing material beneath the flow yielded radiocarbon ages of 16,000 to <2500?BP. These radiocarbon ages are younger than the ⁴⁰Ar/³⁹Ar age, potentially due to contamination of the charcoal by younger carbon that was not removed by the acid–base pre-treatment. We have re-examined the radiocarbon age of Toomba flow using newly sampled charcoal buried beneath the Toomba flow in combination with hydrogen pyrolysis pre-treatment and accelerated mass spectrometer (AMS) measurements. We determined a calibrated radiocarbon age of 20,815–19,726?cal BP (2σ) for the material beneath the Toomba flow. Our radiocarbon age, therefore: (1) is older than previous radiocarbon ages for the Toomba flow, (2) provides the most precise age yet available for the Toomba flow, (3) is in agreement with the ⁴⁰Ar/³⁹Ar age, and (4) validates that hydrogen pyrolysis is a robust and effective pre-treatment method, for subtropical conditions where samples are susceptible to contamination by younger carbon. The Toomba flow erupted during the Last Glacial Maximum, but the preserved surface suggests that the rate of weathering and soil formation has been almost negligible in this region, despite being situated in a subtropical climate that experiences highly variable often intense rainfall.     

115GHz CO Emission from the IRAS Selected Star-Formation Regions

1　ＩｎｔｒｏｄｕｃｔｉｏｎＳｔａｒｆｏｒｍａｔｉｏｎｉｓｏｎｅｏｆｔｈｅｍｏｓｔｅｘｃｉｔｉｎｇｆｉｅｌｄｓｏｆｍｏｄｅｒｎａｓｔｒｏｎｏｍｙ .ＣＯｍｏｌｅｃｕｌａｒｏｕｔ ｆｌｏｗｓｎｅａｒｙｏｕｎｇｓｔｅｌｌａｒｏｂｊｅｃｔｓｗｅｒｅｆｉｒｓｔｄｅｔｅｃｔｅｄｉｎＯｒｉｏｎｒｅｇｉｏｎ (Ｋｗａｎｅｔａｌ.1 976 ) .ＴｈａｎｋｓｔｏｔｈｅｌａｕｎｃｈｉｎｇｏｆＩＲＡＳ (ＩｎｆｒａｒｅｄＡｓｔｒｏｎｏｍｉｃａｌＳａｔｅｌｌｉｔｅ) ,ｔｈｅＩＲＡＳｐｏｉｎｔ ｓｏｕｒｃｅｃａｔａｌｏｇｕｅ(ＰＳＣ) ｐ…     

Young stars in the disk of M82

We present CCD VI_C photometry in a field 1.9 − 1.3 square arcmin and positioned about 3 arcmin north-east of the centre of M82. More than 100 stars have been identified and measured above the photometric limits V = 23^m.5, I = 22^m. Most of the objects fainter than V ≈︁ 20^m should be members of M82 as expected from the statistics of foreground stars. Starlike as well as 2–3 somewhat diffuse objects - candidates of globular clusters - preferentially occupy yellow colours in the colour-magnitude diagram; extreme blue and red objects are missing. The colour-magnitude diagram indicates continuing star formation in this part of the disk. The absence of blue stars is caused by reddening; no convincing explanation is found for the missing red supergiants. Young stars are distributed throughout the whole field, the youngest being concentrated in associations at the SW edge of the field. To cope with the very irregular background created by the galaxy' s main body and with the low contrast of many of the stars against this background, a modified photometric method is introduced in which the background is estimated using the intensities in a ring drawn very tightly around the star in the wings of the point spread function.     

羚珠散对幼鼠反复热惊厥的防治作用及机制研究

目的：通过评价羚珠散对C57BL/6幼鼠反复热惊厥的减轻作用,探讨其防治热惊厥的药效和可能作用机制。方法：将7 d龄C57BL/6幼鼠30只分为空白对照组、模型对照组和治疗组,每组各10只。采用热水浴法干预模型对照组与治疗组,生成惊厥模型,每次诱导前30 min治疗组灌胃给药羚珠散（1.5 g/kg）,模型对照组灌胃同等体积0.9%氯化钠注射液。观察治疗组与模型对照组幼鼠的惊厥潜伏期和惊厥持续时间的差异,通过HE染色比较各组间幼鼠海马体病理组织学差异,通过Real-time PCR与IHC分析比较空白对照组、模型对照组及治疗组幼鼠海马体中Gabbr1和Kcnt1基因的表达差异。结果：经7次热水浴后,模型对照组幼鼠的惊厥潜伏时间为（32.80±3.27）s,治疗组幼鼠的惊厥潜伏时间为（50.90±6.88）s,治疗组的惊厥潜伏时间长于模型对照组（P＜0.05）;模型对照组幼鼠的惊厥持续时间为（104.40±14.37）s,治疗组幼鼠的惊厥持续时间为（45.40±7.10）s,治疗组的惊厥持续时间显著短于模型对照组（P＜0.01）;HE 染色显示热惊厥状态对模型对照组幼鼠海马神经元损伤明显,细胞肿胀、核皱缩,出现空泡现象,治疗组幼鼠海马神经元损伤减轻,细胞水肿及空泡等现象减轻;治疗组幼鼠中Gabbr1和Kcnt1的 mRNA表达水平高于模型对照组幼鼠（P＜0.05）;免疫组化检测幼鼠海马区中Gabbr1和Kcnt1的阳性细胞比例治疗组高于模型对照组（P＜0.01,P＜0.05）。结论：羚珠散具有显著防治幼鼠热惊厥发作的作用,其机制可能与显著提高Gabbr1与Kcnt1表达,增强GABA抑制神经兴奋作用,减轻海马区神经元损伤有关。     

硇洲马尾藻Sargassum naozhouense幼孢子体附着及原生态恢复

【目的】探究硇洲马尾藻(Sargassum naozhouense)幼孢子体附着的选择性及原生态位点固着人工藻礁对马尾藻海藻资源恢复效果。【方法】选用混凝土、黄泥砖、牡蛎壳、聚丙烯板、橡皮条、沥青等6种废弃物材质对硇洲马尾藻幼孢子体附着效果进行比较;将硇洲马尾藻于徐闻南山进行原生态位点投放,周年观察比较人工藻礁与自然藻礁生长差异,探究硇洲马尾藻资源恢复效果。【结果】(1)不同材质藻礁对硇洲马尾藻幼孢子体附着差异显著,附着效果依次为混凝土>黄泥砖>牡蛎壳>聚丙烯板>橡皮条,沥青完全没有幼孢子附着。(2)当年人工藻礁苗有性生殖苗较自然生态苗生长慢,第二年假根再生苗生长与自然苗生长无显著性差异。(3)人工藻礁苗成活率为29.2%,此后不出现消退死亡,并以假根再生维持种群的繁衍。【结论】混凝土是马尾藻原生态藻床恢复较理想的人工附着基,黄泥砖、牡蛎壳、聚丙烯板等废弃物也可用于天然硇洲马尾藻以及室内有性苗源的附着基。假根再生是马尾藻种群繁衍的主要方式,利用有性繁殖的幼孢子体附着于混凝土块上进行硇洲马尾藻原生态位点投放是短时间增加马尾藻资源的有效措施,可为硇洲马尾藻海藻资源恢复提供可行的方法。     

从中国地质学会创立看青年的作为

本文简要回顾了中国地质学会成立的过程,分析了学会成立背景中青年的作用,从制度的建立、奖项设置、组织建设、学术活动上等方面梳理了学会百年历程中对青年会员工作的重视,提出传承优良传统,坚定地质文化自信,丰富并开拓新的服务方式,凝聚广大地质青年,发挥青年会员在学会服务地质科学和经济社会发展中的作用。     

花尾胡椒鲷早期发育阶段的摄食与生长特性

１９９８年４～６月份在集美大学水产学院海水育苗试验场对人工培育的花尾胡椒鲷早期发育阶段的摄食和生长特性进行分析。结果表明,在水温为２５℃时,仔鱼约经６０～７０h 左右开口摄食,开口饵料为经１２０目筛网过滤的褶皱臂尾轮虫,以后随着鱼体的生长,依次投喂卤虫无节幼体和桡足类。对３７２尾仔、幼鱼解剖观察结果,摄食率达９７．０％,摄食量占体重的６．４％～２３．４％,日摄食量占休重的２４．８％～８３．７％,摄取