晚更新世以来内伶仃洋河口湾的地层层序和沉积演化

通过对内伶仃洋河口湾22个钻孔沉积物的高分辨14C测年、古生物鉴定、沉积物粒度及地球化学分析,开展了晚更新世地层划分,探讨了晚更新世以来的沉积演化过程。内伶仃洋河口湾地层被含花斑黏土层的风化层隔开,划分为上下2组,侵蚀面上下分别为全新统和上更新统地层。受晚更新世以来2次海侵的影响,内伶仃洋河口湾沉积演化分成了6个阶段,详细阐述了每个阶段的气候变化、海平面波动、沉积特征和沉积过程。     

中国第四纪冰期数值年表初步划分

20世纪70年代以前,我国第四纪冰川冰期主要是根据第四纪冰川遗迹的侵蚀-沉积地貌特征和沉积物的物理化学风化程度的差异划分的相对年代;80～90年代开始有放射性碳和地衣法的测年;90年代以后,采用热释光和电子自旋共振技术测年,获得了我国第四纪冰川的一些数值年代,划分了5次冰期,其时代初步定为:小冰期Ⅲ(1871±20A.D.),小冰期Ⅱ(1777±20A.D.),小冰期Ⅰ(1528±20A.D.);新冰期Ⅲ(1550±70aB.P.,1580±60aB.P.),新冰期Ⅱ(2.8～2.5kaB.P.),新冰期Ⅰ(3.1kaB.P.);末次冰期Ⅳ(YD)(11.5～10.4kaB.P.),末次冰期Ⅲ(24～16kaB.P.),末次冰期Ⅱ(56～40kaB.P.),末次冰期Ⅰ(73～72kaB.P.);倒数第二冰期(相当于MIS6～10),Ⅲ阶段(154～136kaB.P.),Ⅱ阶段(277～266kaB.P.),Ⅰ阶段(333～316kaB.P.);倒数第三冰期(相当于MIS12～16),Ⅱ阶段(520～460kaB.P.),Ⅰ阶段(710～593kaB.P.)。未来的研究趋势是采用宇宙成因核素暴露年代方法和光释光技术在更大的空间尺度上对冰川地貌精细定年,分析第四纪冰川发育的空间差异和异时性机制。     

Soil evolution features of debris flow waste-shoal land

The reclamation and utilization of debris flow waste-shoal land plays an important role in the mitigation and control of debris flow hazards, which thus contributes a lot to the exploitation of insufficient land resources in mountainous areas and the reduction of losses caused by debris flow. The aim of this paper is to discuss the features and mechanism of soil evolution of debris flow waste-shoal land so as to search for the available modes of its reclamation and utilization. The Jiangjiagou Ravine, a typical debris flow ravine, was selected to study soil evolution features of debris flow waste-shoal land based on the analysis of soil physieochemical properties and soil microstructure. It was found that the soil evolution rates of debris flow waste-shoal land varied with different modes of reclamation. For the land which had been reclaimed for less than lO years, soil evolved most rapidly in paddy fields, and more rapidly in dry farmland than in naturally restored waste-shoal land. For the land which had been used for more than lo years, the soil evolution rates of dry farmland, naturally restored waste-shoal land and paddy farmland decreased in the file. For the same utilization period of time, significant differences were recognized in soil evolution features under different modes of reclamation. Analysis data showed that soil clay content, soil thickness, the psephicity of skeleton particles and contents of microaggregates （〈0.02 mm） in paddy farmland were all highest. Soil nutrients and porosity of dry farmland were better than those of paddy farmland and naturally restored waste-shoal land, and those of paddy farmland were superior to those of naturally restored waste-shoal land. Paddy farmland characterized by rapid pedogenesis, stable evolution and high utilizability was the priority candidate for the reclamation and utilization of debris flow waste -shoal land.     

蒙古国东南部巴音苏赫图晚古生代—早中生代二长花岗岩地球化学特征及其对构造环境的约束

巴音苏赫图二长花岗岩位于西伯利亚板块东南缘陆缘增生带与二连—贺根山板块对接带北缘之间。该岩体由石炭纪及三叠—侏罗纪两期花岗岩组成,均以高硅、富Al2O3、K2O、Na2O,贫MgO、CaO为特征。微量元素表现为富集LILE、亏损HFSE。弱富集LREE,Eu负异常明显。岩石学和地球化学综合研究表明:两期花岗岩早期为高钾钙碱性、准铝质-过铝质花岗岩碰撞期I型花岗岩,晚期花岗岩具有A型花岗岩特点。Sr-Nd同位素研究表明:石炭纪二长花岗岩(87Sr/86Sr)i比值较低(0.700 62～0.704 82),εNd(t)为正值(0.9～1.5),岩浆来自于增生的岛弧或年轻的幔源物质,在岩浆上升过程中遭受了少量地壳物质的混染;晚三叠世—早侏罗世花岗岩(87Sr/86Sr)i比值较高(0.709 96～0.710 19),εNd(t)较低,为-0.3～0.3,该期次花岗岩与晚石炭世花岗岩同源,受地壳混染程度相对较高。应用LA-ICP-MS法测得石炭纪花岗岩U-Pb年龄为(296±3.5)Ma,结合区域构造演化特点及所测三叠纪花岗岩的地球化学特征认为,在晚石炭世,南蒙古额尔德尼查干地区已进入碰撞期构造环境,在三叠—侏罗纪仍有同碰撞花岗岩侵入,晚石炭世以后的碰撞期持续时间较长。     

通过第一性原理预测内地核的成分与结构

内地核成分与结构的确定一直是地球深部研究的重要课题。目前地核的公认成分是铁和少量的镍。但由于地核密度低于纯粹的铁镍合金(固态内核2%～3%,液态外核6%～7%),其中必定掺杂有一定量的轻元素,其种类与浓度有待确定。除成分外,地核条件下铁的晶体结构也存在争议。根据地震学观测,声波沿地轴方向的传播速度比赤道平面方向快大约3%～4%。这意味着内地核是各向异性的;但在极端高压下,晶体结构中的原子应该按致密的密排六方结构(h.c.p)排列,而h.c.p结构对声波传输是高度各向同性的,这就需要确定地核条件下铁的晶体结构。根据第一性原理计算得到的高压下体系能量以及爱因斯坦谐振子模型,本项研究估算了给定结构的自由能以及掺杂轻元素后的影响。根据计算结果可以定性的分析得出,在高压OK下致密的h.c.p结构显然比疏松的体心立方(b.c.c)更稳定;而随着温度的升高,原子核的振动造成b.c.c结构的自由能比h.c.p结构下降得更快,因此在高温下b.c.c结构更稳定;掺杂轻元素后,这种优势变得更加明显,而3.6at.%的Si则恰好同时解释了2%～3%的密度缺失和b.c.c结构在内地核条件下的稳定性。因此我们建议内地核的基本结构与成分应为以体心立方结构存在的铁,掺杂约3.6at.%的硅元素,内地核温度至少在5500K以上。这一结论与其它更复杂的方法得到的结果一致。     

鲁西金岭矽卡岩型铁矿区早白垩世石英闪长岩成因:年代学和地球化学证据

金岭岩体是鲁西地区代表性的中生代侵入杂岩体,与金岭矽卡岩型铁矿的成因密切相关.为了解石英闪长岩的成因及与矽卡岩铁矿成矿关系,本次研究对金岭杂岩体中的石英闪长岩进行了年代学、地球化学及锆石Lu—Hf同位素和角闪石矿物微区成分的系统研究.LA-ICP-MS锆石U-Pb年代学显示石英闪长岩加权平均年龄为(128±1)Ma,侵...     

太阳活动区磁场观测的一种新方法

在太阳活动区的物理研究中,特别是在二维动力学光谱分析中,迫切需要相应活动区的磁图资料。本文介绍了在太阳光谱仪的入射狭缝后安装一种新型偏振器进行活动区二维磁场观测的新方法。这种方法不仅能获得日面上任一点的磁场强度,且可快速获得活动区的纵向场磁图。除此之外,还可利用多条谱线的同时观测,获得有关磁力线管结构等方面的资料。     

青藏块体东北缘地壳水平运动状态

应用青藏块体东北缘1999～2003年多期GPS观测资料，计算了不同时段GPS点水平运动速率。通过分析发现：甘青块体可分为东部块体和西部块体，东、西部块体的运动状态存在明显的差异；受2001年11月14日昆仑Ms8．1地震的影响，震后地壳运动状态发生了明显的改变。     

基于各向异性致密砂岩油地震岩石物理模型的脆性指数研究（英文）

致密砂岩油储层的脆性研究是致密砂岩油地震预测的重要内容,需要引入合适的脆性指数来建立致密砂岩油储层的脆性评价标准。本文首先构建了各向异性致密砂岩油地震岩石物理模型;依据该模型进行了各向异性介质弹性常数的脆性敏感性分析,建立了新的脆性指数;并分别从脆性敏感性定量分析、岩石物理响应特征分析以及交汇图分析三个方面系统研究了新脆性指数在致密砂岩油脆性预测上的适用性。分析结果表明,新脆性指数较其它传统脆性指数,不仅其脆性敏感性高,而且更适合于致密砂岩油储层"甜点"区的脆性预测。     

Extraction and PTP1B inhibitory activity of bromophenols from the marine red alga Symphyocladia latiuscula

Previously, we had characterized several structurally interesting brominated phenols from the marine red alga Symphyocladia latiuscula collected from various sites. However, Phytochemical investigations on this species collected from the Weihai coastline of Shandong Province remains blank. Therefore, we characterized the chemical constituents of individuals of this species collected from the region. Eight bromophenols were isolated and identified. Using detailed spectroscopic techniques and comparisons with published data, these compounds were identified as 2,3-dibromo-4,5-dihydroxybenzyl methyl ether (1), 3,5-dibromo-4-hydroxybenzoic acid (2), 2,3,6-tribromo-4,5-dihydroxymethylbenzene (3), 2,3,6-tribromo-4,5-dihydroxybenzaldehyde (4), 2,3,6-tribromo-4,5-dihydroxybenzyl methyl ether (5), bis(2,3,6-tribromo-4,5-dihydroxyphenyl)methane (6), 1,2-bis(2,3,6-tribromo-4,5-dihydroxyphenyl)-ethane (7), and 1-(2,3,6-tribromo-4,5-dihydroxybenzyl)-pyrrolidin-2-one (8). Among these compounds, 1 and 2 were isolated for the first time from S. latiuscula. Each compound was evaluated on the ability to inhibit protein tyrosine phosphatase 1B (PTP1B), which is a potential therapeutic target in the treatment of type 2 diabetes. Bromophenols 5, 6, and 7 showed strong activities with IC50 values of 3.9, 4.3, and 3.5 μmol/L, respectively. This study provides further evidence that bromophenols are predominant among the chemical constituents of Symphyocladia, and that some of these compounds may be candidates for the development of anti-diabetes drugs.