共查询到19条相似文献，搜索用时 177 毫秒
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依据克莱门汀号和月球勘探者号月球探测器所获得的数据所建立最新的地球重力模型和地形模型，为人类深入了解月球内部性质及其演化特征，提供新的平台.M.T. Zuber (1994) 和 M. A. Wieczorek (1998) 所建立的月壳全球模型，为利用最新月球着力资料研究月球内部构造和演化，揭示月球上独特的“物质瘤”之成因等科学问题，开凿了先河.本文通过对现有的月球重力和地形数进行分析和计算，提出作者对月球内部物质分布特征的理解和一些认识.从宏观角度看，月球布格重力异常与月球地形起伏是相关的，统计结果表明它们呈弱负相关，从均衡角度来说，在月球停止大规模内部物质运动之前，月球壳幔可能已基本达到均衡；从Mascon深度估算结果来看，一些大型的Mascon基本属于玄武岩浆“充填”型的，少数Mascon可能与月幔柱有关，如东方海Mascon. 相似文献
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雨海盆地是月球正面最大的撞击盆地之一,确定其月壳与上月幔精细三维结构,对研究月球“质量瘤”形成机制等科学问题具有重要意义.常用于反演月壳与上月幔结构的月震波方法受限于月震台站稀少,给出三维结果的空间分辨率不足.随着重力测量技术的发展,月球重力数据横向分辨率逐步提高,但存在垂向分辨率不足问题.鉴于此,本文采用重力多尺度分析方法来进行改善,以获取研究区域月壳与上月幔精细三维密度结构与壳幔界面深度.研究结果表明：雨海盆地内部存在一个顶部小、底部大的高密度物质体,其底部中心位置约为经度16°W,纬度42°N;雨海盆地壳幔界面存在明显上隆,且盆地内部上隆趋势不平滑,发现有类环状异变现象;雨海“质量瘤”可能是由内部高密度物质和壳幔上隆共同推动形成的;重力多尺度分析方法可以有效提升重力数据的垂向识别能力,获取更为精细的三维月壳与上月幔结构. 相似文献
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在频域使用多窗口(Multitaper)方法来计算月球正面四个形成于不同历史时期月海区(Smythii, Crisium, Imbrium, Orientale)的重力地形导纳,然后将其与月球弹性岩石圈的理论导纳模型相比较,由最小二乘法得出四个月海区的月球岩石圈的平均弹性厚度约为8 km,月壳的厚度分别为：Smythii 盆地,72 km; Crisium 盆地 70 km;Orientale 盆地 60 km;Imbrium 盆地57 km.随着月球的演化,月壳厚度呈现变厚的趋势. 相似文献
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在地球、太阳和其他行星的引潮力的作用下,月球表面上任一点重力值将产生周期性的变化称为月球重力固体潮理论值.研究月球重力固体潮有助于我们更好地了解月球的内部结构、地壳运动以及月球的演化过程,这也为登月任务和月球探测提供了重要的科学依据,帮助我们更好地探索和理解月球的特性和性质.本文阐明了月球重力固体潮形成原因,根据category5月球内部结构模型计算出月球重力潮汐因子,依据Newcomb理论,采用ELP2000-85解析星历和Eckhardt月球天平动模型,提出一个计算月球重力固体潮理论值的方法,选取Apollo11作为测站,以波形图的形式输出该测站一天、一个月、一年的月球重力固体潮理论值,并探索讨论月球重力固体潮与月震的关系.结果表明：该测站一天、一个月、一年的月球重力固体潮理论值,最大值分别为：-1309μGal、-1290μGal、-1277μGal;最小值分别为：-1343μGal、-2349μGal、-2349μGal;与地球重力固体潮(这里选择与Apollo11经度纬度相同的坐标作为测站相比),月球重力固体潮变化相对简单,但波动幅度较大;推测月球的重力固体潮与深源月震之间可... 相似文献
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传统的折射与广角反射地震和重力数据的联合解译是基于大量地壳岩石弹性性质实验室研究证实的地震P波速度和密度之间众所周知的相关性。与这一方法相矛盾的一个问题是富含钙长石的岩石具较高的P波速度,而不满足常规密度—VP关系。这说明基于常规密度—VP关系的联合反演不适用于横跨大的非造山带环斑-辉长-斜长岩地块的广角地震调查,因为其组成成分富含斜长石。同时使用VP和VS计算密度模型就可解决这一问题。岩石属性的实验室结果表明密度与VS相关性很强。此外,各向同性VS与密度的相关性较VP更强,且受高斜长石含量的影响更小。即便如此,利用这一已知的密度与VS或者密度与VP及VS的相关性进行地震和重力数据的联合反演仍然十分少见。其重要原因在于暴破地震学中S波波至的质量低,因而难以得到可靠的S波速度模型。本文阐述了在乌克兰地盾EUROBRIDGE’97广角反射和折射剖面所做的地震和重力数据联合反演的结果。该区缺失厚沉积体,使我们可以得到P波和S波速度模型。通过重力反演得到EUROBRIDGE’97剖面密度模型,我们利用密度和VP、VS模型的关系,将密度模型参数化。这样参数化后,经重力数据转换,可以获得密度和地震波速的关系。结果显示EUROBRIDGE’97剖面的密度与地震波速之间呈非线性和离散的关系。对相关性的分析表明,造成离散是缘于横跨该剖面的大的地质构造单元的差异。为解释这一差异,我们对比EUROBRIDGE’97剖面上3个主要地质单元中地震速度和密度的关系和来自乌克兰地盾及另一个前寒武纪地区的岩石学资料。可见与平均密度—速度关系的偏移量是岩石的特殊矿物组合的反映,包含了不同的岩石时代和地壳形成环境。论述了如何通过密度—速度图分析,来限定地壳成分,尤其是下地壳的成分和变质程度。 相似文献
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月球地质年代表将月球的地层按形成的时间顺序划分为不同的时代,能够清晰地表达月球的整体演化历史.在地基望远镜观测和阿波罗时代早期,由于当时所用数据的空间覆盖度和分辨率有限,所建立的月球地质年代划分存在部分缺陷.在阿波罗时代结束以来的几十年里,人类对月球进行了更广泛的研究,拓展了对全月地质演化的认识和理解.基于对月球动力学演化的综合性分析,本文对当前的月球地质年代表进行了更新,特别考虑了内动力地质作用和外动力地质作用在月球早期演化中所发挥的作用.首先,根据内动力和外动力在不同时期对月球改造的效应,提出了三阶段月球动力学演化模型,并建立了三个相应的“宙/宇”级别的年代及地层单元.其次,为了更清晰地反映月球的演化历史,以南极-艾肯(SPA)盆地的形成为界线将前酒海纪划分为了岩浆洋纪和艾肯纪,其中较年轻的艾肯纪是以SPA盆地的形成为起点.本文识别了SPA盆地的溅射物地层,即达斯建造,其沉积在月球的原始月壳上,是岩浆洋结束后保存下来的最古老的外动力成因地层.更新的月球地质年代表系统综合了阿波罗时期以来月球探测和研究的成果,构建了一个描述月球演化历史的系统框架,能够更方便地开展月球地质研究,对其他类... 相似文献
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月表太阳辐射是深入研究月表温度分布的关键问题之一. 本文根据月表有效太阳辐照度与太阳常数、太阳辐射入射角以及日月距离之间的关系,建立月表有效太阳辐照度的实时模型. 该模型在1950～2050年的100年内的理论误差百分比小于0.28％, 相对前人提出的模型在精度上有了很大程度的提高,能较为真实地反映月表有效太阳辐照度随时间的变化规律. 计算结果表明2007年月表太阳辐照度的年变化范围在1321.5～1416.6 W·m-2之间,平均为1368.0 W·m-2. 通过对月表太阳辐射入射角计算结果的分析,证实了月球的两极可能存在极昼极夜. 相似文献
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The Sm-Nd systematics of lunar KREEP basalt 15386 reflects two chronologically distinct events in the development of the incompatible element-rich materials of the moon. The measured Sm-Nd mineral isochron of 15386 indicates an age of 3.85 ± 0.08 AE which is consistent with the reported Rb-Sr and39Ar-40Ar ages of many other KREEP-rich samples. This age is interpreted as the time at which 15386 crystallized from a liquid on or near the lunar surface. The frequent occurrence of this age for KREEP-dominated samples, as well as the restricted location of KREEP near major lunar near-side impact basins, suggests that the eruption of these incompatible element-rich liquids was related to deep impact events during the postulated final bombardment phase of the surface of the moon. However, the lower than chrondritic initial143Nd/144Nd of 15386 and the essentially identical Sm-Nd evolution of other KREEP-rich samples require that the light REE enrichment which characterizes KREEP was established considerably before 3.85 AE. Within the limits imposed by model assumptions in the various radiometric systems, it is concluded that the extremely narrow spread of Sm-Nd model ages for these samples around 4.36 AE, and the compatibility of this age with that indicated by the U-Pb and Rb-Sr systems, indicate that the source of later KREEP volcanism was produced in the closing stages of an early global scale lunar differentiation episode. 相似文献
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本文介绍了"嫦娥一号"月球探测卫星轨道跟踪数据的特征,简要阐述了基于动力法精密定轨解算月球重力场模型的原理及策略.在"嫦娥一号"测控数据精度和覆盖均有限的条件下,独立使用"嫦娥一号"月球探测器6个月的在轨运行双程测距测速跟踪数据,成功得到了50阶次月球重力场模型CEGM-01.通过多种方式,如重力场模型频谱特性、实测数据定轨残差、月球重力异常特征、与地形的相关性及导纳值,对解算得到的CEGM-01月球重力场模型进行了精度评价,分析了相应的物理特性和效果.结果表明了CEGM-01解算过程的有效合理.在此基础上展望了我国月球重力场探测未来可能的发展方向. 相似文献
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本文基于绕月卫星跟踪技术的三种模式,即地面跟踪模式、高低跟踪模式和低低跟踪模式,将月球重力场的发展历程分为四个阶段.分别介绍了各阶段跟踪模式的主要原理、技术特点以及所获取的具有代表性的重力场模型,并对这些模型的精度特征进行了评述.进而,通过分析不同阶段重力场模型所获取的月球重力异常特征和精度、不同阶段重力场模型的定轨精度,阐明了:空间跟踪技术的进步,极大地提高了月球重力场模型的精度,并且,有效地促进了对月球物质结构特征的认识和绕月卫星定轨的可靠性.最后对月球重力场模型中尚存在的问题以及探测技术的发展前景进行了分析和展望. 相似文献
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The Apollo 17 KREEPy basalt is a unique lunar volcanic rock, observed only as clasts in the light friable breccia matrix (72275) of Boulder 1, Station 2 at Taurus-Littrow. Its status as a volcanic rock is confirmed by the absence of any meteoritic contamination, a lack of cognate inclusions or xenocrystal material, and low Ni contents in metal grains.The basalt was extruded 4.01 ± 0.04 b.y. ago, approximately contemporaneously with the high-alumina mare basalts at Fra Mauro; shortly afterwards it was disrupted, probably by the Serenitatis impact, and its fragments emplaced in the South Massif. The basalt, which is quartz-normative and aluminous, is chemically and mineralogically intermediate between the Apollo 15 KREEP basalts and the high-alumina mare basalts in most respects. It consists mainly of plagioclase and pigeonitic pyroxene in approximately equal amounts, and 10–30% of mesostatis. Minor phases outside of the mesostatis are chromite, a silica mineral, Fe-metal, and rare olivine; the mesostatis consists primarily of ilmenite, Fe-metal, troilite, and ferroaugite, set in a glassy or microcrystalline Si-rich base.Chemical and isotopic data indicate that an origin by partial melting of a distinct source region is more probable than hybridization or contamination of magmas, and is responsible for the transitional composition of the basalt. The moon did not produce two completely distinct volcanic groups, the KREEP basalts and the mare/mare-like basalts; some intermediate rock types were generated as well. A corresponding spectrum of source regions must exist in the interior of the moon. 相似文献
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W.V. Boynton C.-L. Chou R.W. Bild P.A. Baedecker J.T. Wasson 《Earth and Planetary Science Letters》1976,29(1):21-33
Three Apollo-16 soils, 61220, 63500 and 65500, having diverse properties were separated into six size fractions and analyzed for 8 volatiles and siderophiles. Relative concentrations of an additional 20 elements were determined in 61220 and 63500. The volatile elements Cd, Zn, In and Ga increase in concentration with decreasing grain size; in the finest fractions the increase is roughly parallel to the increase in specific surface area, and a surface correlation is inferred. The total increase from coarsest (177–500 μm) to finest (<5 μm) fraction is by factors of 10–20 for Zn and Cd in soils 61220 and 63500. Concentrations of elements that are good indicators of KREEP (Sm), mare basalts (Fe) and anorthosites (Ca) show nearly no dependence on size. The preservation of the observed surface correlation throughout regolith evolution suggests that the volatile elements are labile on the lunar surface.Concentration-size distributions of siderophiles show peaks in the 80–300 μm range for each soil, independent of whether they are dominantly extralunar (Ni, Ge, Au, Ir) or lunar (Co) in origin. If this peak results from agglutinate formation, a viable mechanism must allow for incorporation of the extralunar siderophiles. Alternatively, the peak may result from a continuous growth of metal grain size during the evolution of the regolith. 相似文献
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A new model accounting for the origin of anomalously high elevations of the Siberian platform (SP) topography is presented. It is shown that the traditional interpretation of these topographic anomalies is at variance with the available evidence for the geological history of the SP development. The ideas elaborated in the paper are based on the concept of the formation of a mantle plume that has led to the supply of large volumes of molten material into the upper crust and surface basalt eruptions. A new approach is proposed for the construction of a density model of the Siberian upper mantle. A density model of the crust based on the available seismic and petrological data is constructed at the first stage. The calculated anomalous gravity field produced by this model is then subtracted from the observed field. The resulting residual mantle anomalies are used, together with seismological data, for the construction of an upper mantle density model. The formation of the present SP topography is shown to have been controlled by the thickening of the crust due to underplating caused by the development of a giant mantle plume at 251 Ma. 相似文献
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月球重力场制约着近月外空间物体的运动,同时环月飞行器的运动也反映了月球重力场的作用. 本文结合我国嫦娥一号探月工程,探讨了利用月球卫星的地面跟踪资料,求定月球重力场的基本理论和方法,分析了环月卫星的轨道高度、地面跟踪采样时间间隔和跟踪精度等对求定月球重力场的影响. 若单独利用我国嫦娥一号探月工程的地面跟踪数据,恢复30阶次左右的月球重力场模型是一个比较实际的目标. 地面跟踪最好能以75s的时间间隔进行采样,数据连续提供时间应不少于30个昼夜,月球卫星星下点的月面轨迹间距不大于110km. 相似文献
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The increased popularity of airborne measurements of the gravity gradient tensor for resource studies and geological mapping has resulted in a new awareness of the importance of terrain effects. In these measurements, the terrain effect often overwhelms that of the underlying crust and it becomes important to formulate a strategy for taking it into account when presenting the data and when inverting the data into density models. Using newly acquired data from Northern Sweden, we first attempted to estimate a variable terrain density model by inverting the data using a terrain model with a laterally varying density. Using data weights related to the topography variations, we find the best estimate of the lateral variation of the terrain density. We translate this model into a full three-dimensional model such that all columns have the same vertical centre of mass as estimated from inspecting the radially averaged power spectrum of the area. This then defines a reference model for subsequent three-dimensional inversion of the gravity gradient tensor dataset. We tested this approach first on synthetic data calculated from the measured topography including two density anomalies before we applied it to the measured data. The result is a model in which the surface density variations are propagated downwards in a systematic manner now in better agreement with measured densities of rock samples in the area. 相似文献