Shatter cones at sierra madera, Texas

Shatter cones abound in the central uplift of Sierra Madera and they occur as far as 6.5 kilometers from the center. Apical angles average near 90 degrees. Whole cones and full cones represented by diversely oriented cone segments in any structural block show relatively uniform orientations of axes and a dominant direction of point. The cones predate faulting and folding in the central uplift, and, when beds are restored to horizontal, most cones point inward and upward, a pattern that supports the hypothesis of an impact origin.     

Structural pattern in central uplifts of cryptoexplosion structures as typified by sierra madera

The pattern of deformation in central uplifts of Sierra Madera and other well-known cryptoexplosion structures indicates that inward as well as upward movement of strata formed the uplifts. This kind of movement is incompatible with structures not of impact origin with which they have been compared. The structural style of cryptoexplosion structures, together with features that suggest shock deformation, supports the belief that they are the eroded roots of impact craters.     

Large trench-parallel gravity variations predict seismogenic behavior in subduction zones

We demonstrate that great earthquakes occur predominantly in regions with a strongly negative trench-parallel gravity anomaly (TPGA), whereas regions with strongly positive TPGA are relatively aseismic. These observations suggest that, over time scales up to at least 1 million years, spatial variations of seismogenic behavior within a given subduction zone are stationary and linked to the geological structure of the fore-arc. The correlations we observe are consistent with a model in which spatial variations in frictional properties on the plate interface control trench-parellel variations in fore-arc topography, gravity, and seismogenic behavior.     

陕北黄土高原夏季降水异常的变化特征及成因初探

[目的]研究陕北黄土高原夏季降水异常的变化特征及成因.[方法]利用1961 ～ 2008年陕北黄土高原15个测站的夏季降水资料及NCEP/NCAR资料,采用线性趋势估计及合成方法,分析了陕北黄土高原夏季降水的变化特征.[结果]陕北大部分地区夏季降水为减少的趋势,但陕北的西部和南部为增加的趋势.陕北夏季降水有明显的年际及年代际变化特征,20世纪70年代中期至90年代中期为降水相对偏多期,90年代中期以后进入降水偏少期,近年来又有增加的趋势.多雨年在中高纬度地区乌拉尔山西部到贝加尔湖以北为大片的正异常区,表明乌拉尔山有阻塞高压存在;鄂霍次克海以北到贝加尔湖为负异常区.西北太平洋到我国渤海湾以及华北地区为大范围显著正异常区,有利于西太平洋副热带高压的北抬西伸.少雨年的环流配置与此相反,中高纬度为“-、+、-”的波列分布,鄂霍次克海一带为正异常区,西太平洋副高也偏南、偏东.在多雨年,主要的水汽输送来自于东南方向,充沛的水汽造成了陕北夏季降水偏多.少雨年为偏西风转向偏南气流带来的水汽输送,水汽输送明显偏弱且偏东.[结论]该研究为陕北黄土高原夏季降水资源的合理利用提供了参考.     

Uplift in the Fiordland region,New Zealand: implications for incipient subduction

Low-temperature thermochronometry reveals regional Late Cenozoic denudation in Fiordland, New Zealand, consistent with geodynamic models showing uplift of the overriding plate during incipient subduction. The data show a northward progression of exhumation in response to northward migration of the initiation of subduction. The locus of most recent uplift coincides with a large positive Bouguer gravity anomaly within Fiordland. Thermochronometrically deduced crustal thinning, anomalous gravity, and estimates of surface uplift are all consistent with approximately 2 kilometers of dynamic support. This amount of dynamic support is in accord with geodynamic predictions, suggesting that we have dated the initiation of subduction adjacent to Fiordland.     

Crustal processes of the mid-ocean ridge

Independent geological and geophysical investigations of the Mid-Ocean Ridge system have begun to focus on the nature of the magma chamber system underlying its central axis. Thermal models predict the existence of a steady-state chamber beneath a thin crustal lid ranging in thickness from 2 to 13 kilometers. The only aspect of the system that these models fail to account for is the extremely slow spreading rates. Seismological studies reveal the existence of a low-velocity zone beneath segments of the East Pacific Rise, which is thought to correspond to a chamber system having a half-width of approximately 5 to 10 kilometers. These estimates compare favorably with those derived separately through petrological investigations of deep-sea drilling results, various sampling programs, and field and laboratory studies of ophiolites. The chamber is thought to be wing-shaped and to remain continuously open; it is thought to be fed from the center while simultaneously solidifying at the sides as spreading carries the two halves apart. Progressive fractionation occurs by crystal settling coupled with repeated replenishment and magma mixing in an open steady-state system. Near-bottom studies reveal that the zone of extrusion above the chamber is narrow, but its eruptive history is cyclic in nature, in conflict with the predictions of a steady-state model. On-bottom gravity data at 21 degrees N on the East Pacific Rise reveal a negative gravity anomaly that may be related to the uppermost part of the chamber. The anomaly is only 2 kilometers wide and 1 kilometer below the sea floor. This feature may be associated with a short-term upper magma reservoir. The cyclic volcanic activity is directly related to the active phase of hydrothermal circulation responsible for the observed negative thermal anomaly. The volume of water associated with this circulation is equal to the entire ocean volume passing through the accretion zone approximately every 8 million years. This is about 0.5 percent of the world's rivers, but the effective transport rates of elements are comparable to those of rivers in that anomalies for individual elements are frequently between 100 and 1000 times the average river composition. The degree of subsurface dilution determines the final exit temperature and composition of the hydrothermal fluids, ranging from manganese domination at extreme dilution to iron at intermediate levels to sulfide deposition when low dilution occurs. The discovery of massive sulfide deposits on the East Pacific Rise is destined to have a profound impact on our understanding of ore-forming processes. Whether it will have any economic significance remains to be seen.     

A rotating solar magnetic " dipole" observed from 1926 to 1968

A recurring pattern with a period of 26(7/8) days observed in the polar geomagnetic field during the interval from 1926 to 1941 appears to persist in the interplanetary magnetic field polarity observed with spacecraft during the interval from 1963 to 1968. This observation suggests the existence of a rotating solar magnetic "dipole" with a period of 26(7/8) +/- 0.003 days.     

日本以南黑潮流量对西北太平洋柔鱼渔场重心影响的滞后性分析

为研究西北太平洋海域黑潮流量对柔鱼Ommastrephes bartramii渔场的影响,本研究中结合1994—2010年西北太平洋海域黑潮流量和柔鱼渔场重心数据,采用阿尔蒙法建立了多项式分布滞后模型,通过分析黑潮流量异常与渔场重心偏移的互相关系数和模型的AIC值,确定了模型的最佳滞后期数,并添加了一阶滞后残差项以消除残差序列的自相关。结果表明:在经度方向上,黑潮流量异常在一年内对柔鱼渔场重心偏移没有明显的影响;而在纬度方向上,模型中黑潮流量异常变量的第12~15期系数均显著,分别为0.003 72(P0.05)、0.004 93(P0.01)、0.006 29(P0.01)和0.007 81(P0.05),说明黑潮流量异常会在6个月后的两个月内对渔场纬度重心产生正向的影响,模型调整后的相关系数为0.549。本研究中考虑了渔场对黑潮流量响应的时滞性,研究结果对延长西北太平洋柔鱼渔场预报的有效期限具有一定的参考意义。     

我国"三农"问题与城市化战略

从我国城市化发展进程中可知，水平低、发展慢、地区分布不合理、城市功能不足，是我国城市化中存在的主要问题，也是产生我国“三农”问题的根源。本文认为加快城市化步伐、走多元化的城市化道路是解决“三农”问题的必然选择。提出了加快城市化步伐的基本思路。指出“二元城市化”是我国城市化的实现方式，强调“城市化农村”是我国城市化的应有主题。     

Moonquakes

Although the average rate of seismic energy release within the moon appears to be far below that of the earth, over 100 events believed to be moonquakes have been recorded by the two seismic stations installed on the lunar surface during Apollo missions 12 and 14. With few exceptions, the moonquakes occur at monthly intervals near times of perigee and apogee and show correlations with the longer-term (7-month) lunar gravity variations. The repeating moonquakes are believed to occur at not less than 10 different locations. However, a single focal zone accounts for 80 percent of the total seismic energy detected. This active zone appears to be 600 kilometers south-southwest of the Apollo 12 and 14 sites and deep within the moon. Each focal zone must be small (less than 10 kilometers in linear dimension) and fixed in location over a 14-month period. Cumulative strain at each location is inferred. Thus, the moonquakes appear to be releasing internal strain of unknown origin, the release being triggered by tidal stresses.     

Magnetic field studies by voyager 2: preliminary results at saturn

Further studies of the Saturnian magnetosphere and planetary magnetic field by Voyager 2 have substantiated the earlier results derived from Voyager 1 observations in 1980. The magnetic field is primarily that of a centered dipole (moment = 0.21 gauss-RS(3); where one Saturn radius, RS, is 60,330 kilometers) tilted approximately 0.8 degrees from the rotation axis. Near closest approach to Saturn, Voyager 2 traversed a kronographic longitude and latitude range that was complementary to that of Voyager 1. Somewhat surprisingly, no evidence was found in the data or the analysis for any large-scale magnetic anomaly in the northern hemisphere which could be associated with the periodic modulation of Saturnian kilometric radiation radio emissions. Voyager 2 crossed the magnetopause of a relatively compressed Saturnian magnetosphere at 18.5 RS while inbound near the noon meridian. Outbound, near the dawn meridian, the magnetosphere had expanded considerably and the magnetopause boundary was not observed until the spacecraft reached 48.4 to 50.9 RS and possibly beyond. Throughout the outbound magnetosphere passage, a period of 46 hours (4.5 Saturn rotations), the field was relatively steady and smooth showing no evidence for any azimuthal asymmetry or magnetic anomaly in the planetary field. We are thus left with a rather enigmatic situation to understand the basic source of Saturnian kilometric radiation modulation, other than the small dipole tilt.     

Significance of "tethyan" fossils in the american cordillera

Equatorial faunas of the ancient Tethyan seaway, which extended from western Europe to southeastern Asia, comprise some of the most diverse marine taxa in the fossil record. Comparable or identical "Tethyan" species that occur far from the Tethyan seaway in Paleozoic and Mesozoic rocks of the North and South American Cordillera have long been considered as a major biogeographic anomaly. Two leading theories to account for the occurrence of these anomalous "Tethyan" faunas in the Cordillera are that they were transported long distances to the east on tectonic blocks(suspect terranes that originated near the Tethys) or that they migrated westward via undiscovered marine corridors through continental areas of Pangea. An alternative model is that these "Tethyan" fauna were pantropic species that extended with attenuated diversities into the eastern proto-Pacific Ocean. This pantropic model can better account for the distribution patterns of many Paleozoic and early Mesozoic "Tethyan" species in the American Cordillera and provides a steady state hypothesis against which the other models can be tested. The distribution of pre-Cretaceous "Tethyan" faunas is similar to the known pantropic distribution of many Cretaceous and Cenozoic tropical biotas. During the Cenozoic, taxa were most diverse in the Tethys and Indo-West Pacific regions but extended with attenuated diversity to many parts of the equatorial Pacific Ocean, including the west coasts of North and South America. The eastern Pacific occurrence of many Indo-West Pacific species provides a modern analog for the occurrence of many anomalous "Tethyan" fossils in the American Cordillera.     

关中盆地包气带中“三氮”的分布特征及影响因素分析

通过野外采样和室内测定,运用统计学的方法分析了关中盆地包气带中三氮的分布特征,并对影响三氮分布的因素进行了研究。结果表明,研究区包气带中氮素主要以NO3-的形式存在,且随着包气带埋深的增加呈波动下降的趋势;NH4+含量较低,在包气带中变化幅度较小;包气带中三氮主要积累在1.0 m以上。单一结构包气带中三氮含量逐渐下降,多层结构中三氮含量呈波动式下降,且在两种岩性界面处发生突变。土地利用类型对"三氮"的分布也有较大影响,蔬菜地表三氮含量高,荒地地表三氮含量低,农作物地表三氮含量居中。环境条件(pH、含水率、氧化还原电位等)也对三氮的分布特征具有一定的影响。     

The dark night-sky riddle: a "paradox" that resisted solution

The riddle of a dark night sky, now known as "Olbers's paradox," can be traced back to Thomas Digges in 1576. Since the time of Edmund Halley (1721) the riddle of a dark night sky in an infinite universe uniformly populated with stars has been regarded as a paradox. Constant emphasis on the paradoxical aspect of the problem of darkness at night, however, leads to a one-sided interpretation of the riddle. Calling the phenomenon a "paradox" distorts the historical perspective, and consequently we incorrectly attribute the origin of the riddle to Edmund Halley. Also it distorts the cosmological perspective and quite probably has greatly delayed the solution of the riddle.     

华北地区冬季旱情及大气环流异常分析

利用NCEP/NCAR 1959～2007年东亚月平均网格点再分析资料以及全国756个站点资料,分析了华北典型少雨年和典型多雨年对流层整层大气物理量场的变化特征,并着重对2008年末～2009年初的全国旱情及成因进行了研究。结果表明,华北地区冬季少雨年的基本环流形势,500 hPa高度距平场110°E以东为负距平,以西为正距平,即"西正东负"的形势,温度和风场也均呈现相对应的分布形势;与此相对应,华北地区对流层整层盛行下沉气流;对流层中下层辐散、中上层辐合,华北地区为正涡度距平区,500 hPa水汽从北向南输送,水汽很少;多雨年的环流形势恰好相反。2008年10月～2009年2月华北地区干旱的原因为:中高纬度环流异常,乌拉尔山附近位势高度为正距平区,我国东北和东西伯利亚地区位势高度为负距平区,位势高度的差异反映的是气压的差异,两地产生很大的气压梯度,有强烈的西北风;而这强烈的西北风阻挡了来自渤海的湿润气流,使得气流不能进入我国内陆地区,而取道东北进入东北和西伯利亚,造成了华北地区的此次干旱。     

"Helium spots": caused by a diapiric magma from the upper mantle

"Helium spots," where a significant amount of helium is present in the soil [up to 350 parts per million with a high (3)He to (4)He ratio of (8.90 +/- 0.31) x 10(-6)], have been found along the fault zone formed by the 1966 Matsushiro swarm earthquakes. The formation of the "helium spots" and the occurrence of the earthquakes are interpreted as the results of a diapiric uprise of a magma approximately 1 kilometer in diameter.     

特异观赏桃品种"菊花桃"和"红叶桃"幼树光合特性研究

试验以栽培品种朝晖为对照,对比研究了观赏桃品种菊花桃、红叶桃的光合特性。结果表明,菊花桃、红叶桃9:00、10:00时光合速率低于对照品种朝晖,但红叶桃对弱光的利用能力和菊花桃对低浓度CO2的利用能力较强。试验同时对这些品种的光合特性指标和干物质积累进行相关性分析发现,羧化效率、气孔导度和蒸腾速率与营养生长显著相关。因此在菊花桃、红叶桃用于绿化栽培前,在可控CO2的设施中培育壮苗,同时注意通过控温和控湿调节气孔的运动来调节水分蒸腾,是2个观赏桃栽培的关键步骤。     

“源”园设计理念在现代墓园中的应用探讨

墓园是埋葬死者以及供生者表达怀念和追思的去处,是人类生活的必要组成部分,是城市绿地系统的重要组成部分。根据现代墓园的具体特点和发展方向,提出了以“源”园理念指导现代墓园规划设计的构想,并对何为“源”“源”园的功能和“源”园的主题等内容进行解析。同时,结合案例研究,以“源”园设计理念,通过“源”园结合,以“源”写园,从空间结构、葬式葬法、绿化种植和建筑小品等方面对安徽亳州云都墓园进行规划设计,并对中国今后如何提升现代墓园规划设计水平进行了归纳总结。图1参15     

Vesicle-Specific Noble Gas Analyses of "Popping Rock": Implications for Primordial Noble Gases in Earth

Gases trapped in individual vesicles in the volatile-rich basaltic glass "popping rock" were found to have the same carbon dioxide, helium-4, and argon-40 composition, but a variable 40Ar/36Ar ratio ( approximately 4000 to >/=40,000). The argon-36 is probably surface-adsorbed atmospheric argon; any mantle argon-36 trapped in the vesicles cannot be distinguished from an atmospheric contaminant. Consequently the 40Ar/36Ar ratios and 3He/36Ar ratios (1.45) determined are minimum estimates of the upper mantle composition. Heavy noble gas relative abundances in the mantle resemble solar noble gas abundance patterns, and a solar origin may be common to all primordial mantle noble gases.