Linear and cyclic aliphatic carboxamides of the Murchison meteorite: hydrolyzable derivatives of amino acids and other carboxylic acids

Analyses of fractionated aqueous extracts of the Murchison meteorite by gas chromatography-mass spectrometry after silylation with N-methyl-N (tert-butyldimethylsilyl) trifluoroacetamide have revealed an extensive series of linear and cyclic aliphatic amides. These include monocarboxylic acid amides, dicarboxylic acid monoamides, hydroxy acid amides, lactams, carboxy lactams, lactims, N-acetyl amino acids, and substituted hydantoins. Numerous isomers and homologues through at least C8 were observed in all cases, except for the N-acetyl amino acids and hydantoins. Carboxy lactams, lactams, hydantoins, and N-acetyl amino acids are converted to amino acids by acid hydrolysis, thus, these compounds qualitatively account for the earlier observation of acid-labile amino acid precursors in meteoritic extracts. Laboratory studies of the spontaneous decomposition of N-carbamyl-alpha-amino acids and their dehydration products, the 5-substituted hydantoins, have led to the recognition of a series of aqueous phase reactions by which amino acids and cyanic acid/cyanate ion in the primitive parent body might have given rise to several of the observed classes of amides, as well as to monocarboxylic acids, dicarboxylic acids, and hydroxy acids. A previously undescribed reaction of 5-substituted hydantoins with cyanic acid/cyanate ion to give carboxamides of the 5-substituent groups was observed in the course of these studies. The presence of an extensive suite of amides in a CM chondrite appears to be consistent with the interstellar-parent body formation hypothesis for the organic compounds of these meteorites. The presence of carboxy lactams and lactams along with free amino acids suggests the possibility of further chemical evolution of meteorite amino acids by thermal polymerization. The cyclic amides, given their potential for hydrogen-bonded pair formation, might be considered candidate bases for a primitive sequence coding system.     

中国地震局国际交流与合作信息管理系统客户端应用程序中的若干技术方法

中国地震局国际交流与合作信息管理系统（Ｄｅｐａｒｔｍｅｎｔ ｏｆ Ｉｎｔｅｒｎａｔｉｏｎａｌ Ｃｏｏｐｅｒａｔｉｏｎ Ｎｅｔｗｏｒｋ,简称ＤＩＣｎｅｔ）是由山西省地震局和中国地震局国际合作司共同开发研制的局域网数据库以及适用于中国地震局下属各研究单位和各省地震局外事管理部门的单机版数据库,以满足中国地震局国际地震科学交流与合作方面信息和资料管理工作的需求。该系统是利用ＰｏｗｅｒＢｕｉｌｄｅｒ开发的     

南黄海西部日照海域海侵沉积地层及其古环境意义

南黄海西部日照海域晚更新世海侵沉积地层广泛出露。基于本区18个站位柱状岩芯的剖面观察、有孔虫和介形虫鉴定、粒度分析、腹足类纹沼螺（Parafossarulus striatulus (Benson)）和钙质结核的AMS ¹⁴C年龄识别了沉积相,并探讨了MIS 3阶段的沉积历史和古环境特征,同时大致估算出末次海侵过程中水下平原的剥蚀厚度。结果表明,在日照外海、废黄河水下三角洲以北,表层覆盖着全新世早期海侵过程中所形成的砂质改造层,灰色,席状,无层理,厚度薄,通常在10~40 cm左右。海侵沙席之下为海陆过渡相沉积,可细分为滨岸潟湖相、沙坝相和滨海相等。底栖有孔虫组合几乎都以Ammonia beccarii (Linné) vars.为优势种,其他常见种为Elphidium magellanicum Heron⁃Allen et Earland、Cribrononion subincertum (Asano)、Textularia foliacea Heron⁃Allen &; Earland、 Elphidium advenum (Cushman)、Protelphidium tuberculatum (d'Orbigny)、Cavarotalia annectens (Parker et Jones)和Pararotalia nipponica (Asano)等,指示滨岸浅水沉积环境。地层沉积年代为MIS 3阶段的中期或中早期,当时的海平面波动区间主要位于现今海平面以下20 m至31 m之间。这套地层为海进沉积,是海平面波动过程中所形成的沉积旋回,沉积过程中曾经历过反复的暴露和氧化,从下向上,其垂向层序可分为两个序列：1）滨岸潟湖—沙坝沉积或仅见沙坝沉积,为砂质沉积,分布在海侵沉积区的北部和西部;2）滨岸潟湖—滨海相沉积,为粉砂质沉积,分布在海侵沉积区的东南部。前者沿着古海岸线分布,后者距离古海岸线较远。表层钙质结核的大量富集,可能意味着末次海侵的强度已经剥露至土壤剖面下部的钙积层。据此估计,在末次海侵过程中,本区水下平原的平均剥蚀厚度约为50~70 cm。     

藏南冈底斯带中段始新世岩浆作用的厘定及其大地构造意义

本文对藏南冈底斯带中段的花岗岩类和角闪辉长岩进行了锆石U-Pb年代学和全岩地球化学分析,据此阐明了岩体的形成机制与演化过程,并探讨了成岩时的大地构造背景。分析结果显示,研究区内花岗岩类和角闪辉长岩体的LA-ICPMS锆石U-Pb定年结果为41~55Ma,为始新世早-中期岩浆活动的产物,代表了区内岩体的成岩年龄。在地球化学组成上,花岗岩类属于钙碱性到高钾钙碱性系列,均富集轻稀土(LREE)和大离子亲石元素(LILE)(Rb、Ba和K),强烈亏损Nb、Ta、P等高场强元素(HFSE),具有弧型岩浆岩的地球化学组成。此外,花岗岩类的铝饱和指数(A/CNK)小于1.1,属于准铝质到弱过铝质的I型花岗岩。角闪辉长岩为石榴橄榄岩部分熔融的产物,并在后期侵位的过程中遭受到了壳源物质的混染。综合分析表明,研究区内的岩体形成于初始碰撞向主碰撞的转化阶段。始新世早期(～50Ma)新特提斯洋板片的断离引起软流圈物质上涌,导致岩石圈地幔发生部分熔融形成基性岩浆,随后基性岩浆底侵至下地壳并诱发下地壳发生部分熔融形成花岗岩质岩浆,最后经过岩浆混合作用形成始新世早-中期冈底斯地区的花岗岩类。     

北大巴基性岩墙群地球化学特征、LA-ICP-MS锆石U-Pb定年及其大地构造意义

北大巴地区广泛分布了呈北西-南东向产出的基性岩墙群,主要侵位于下古生界。对该套岩系的地球化学分析表明,w（K2O＋Na2O）、w（TiO2）高,总稀土元素质量分数高并呈轻稀土元素富集型,大离子亲石元素明显富集,Ta、Nb的质量分数远高于洋中脊玄武岩,具大陆裂谷玄武岩的地球化学特征。采用LA-ICP-MS法对北大巴基性岩墙中的岩浆锆石进行了U—Pb同位素定年,获得岩体结晶年龄为（431．0＋3．2）Ma。地球化学及年代学数据表明,北大巴基性岩墙群具有大陆裂谷玄武岩的地球化学特征,表明北大巴早古生代伸展构造受到扬子板块北缘的幔源裂谷作用制约。在裂谷演化过程中,上地幔物质上涌造成岩石圈板块拉伸减薄,使北大巴地区中上地壳发生强烈构造伸展并形成大面积呈线状分布的基性岩墙群,并且该处（431．0±3．2）Ma的年龄值代表了在早志留世北大巴裂谷盆地的伸展裂陷幅度达到最大。     

Metal-organic complexation in the marine environment

We discuss the voltammetric methods that are used to assess metal-organic complexation in seawater. These consist of titration methods using anodic stripping voltammetry (ASV) and cathodic stripping voltammetry competitive ligand experiments (CSV-CLE). These approaches and a kinetic approach using CSV-CLE give similar information on the amount of excess ligand to metal in a sample and the conditional metal ligand stability constant for the excess ligand bound to the metal. CSV-CLE data using different ligands to measure Fe(III) organic complexes are similar. All these methods give conditional stability constants for which the side reaction coefficient for the metal can be corrected but not that for the ligand. Another approach, pseudovoltammetry, provides information on the actual metal-ligand complex(es) in a sample by doing ASV experiments where the deposition potential is varied more negatively in order to destroy the metal-ligand complex. This latter approach gives concentration information on each actual ligand bound to the metal as well as the thermodynamic stability constant of each complex in solution when compared to known metal-ligand complexes. In this case the side reaction coefficients for the metal and ligand are corrected. Thus, this method may not give identical information to the titration methods because the excess ligand in the sample may not be identical to some of the actual ligands binding the metal in the sample.     

西大别造山带新元古代中期双峰式火山岩的发现对扬子陆块北缘构造演化的约束

扬子陆块北缘新元古代中期的构造机制(是俯冲～增生造山、还是后造山-裂谷)是华南新元古代构造演化研究中长期争论的重要科学问题.本文在西大别造山带红安桃花地区新识别出双峰式火山岩,为进一步揭示扬子陆块新元古代中期岩浆-构造演化过程和动力学机制提供了新的制约信息.SIMS和LA-ICP-MS锆石U-Pb定年结果表明,桃花双峰式火山岩形成年龄为750～740 Ma.基性火山岩为拉斑玄武质,显示由正常洋中脊型玄武岩向弧型玄武岩演化的微量元素特征,且具有变化的全岩εNd(t)值(-0.05～+5.96).这些基性火山岩可能是亏损的软流圈地幔在减压条件下部分熔融的产物,岩浆经历了结晶分异和围岩混染.酸性火山岩中,徐门寨样品富硅(SiO2≥75％)和碱(K2O+Na2O≥7％),富集 REE 和 HFSE(如 Zr、Hf、Nb、Y),其 Zr+Ce+Y+Nb≥600 × 10-6,10000Ga/A1≥2.6,与分异A型花岗岩类相似.它们同时具有富集的Hf-Nd同位素组成,其锆石εHf(t)值主要集中在-12.32～-1.88,而全岩εNd(t)值为-13.29～-9.60,可能是区域上新元古代早期的岩浆岩在高温低压条件下部分熔融形成的产物.综合本文和前人的资料表明,南秦岭-桐柏-大别-苏鲁造山带在新元古代中期(780～635 Ma)的双峰式岩浆组合形成于一个软流圈上涌、岩石圈拉张减薄的大陆裂谷环境;高温-低压条件下的软流圈、岩石圈地幔和地壳的熔融及其相互反应,是这一时期不同性质岩浆形成的主要原因.