GPS变形监测中提取大变形量的单历元解算方法研究

提出一种综合利用宽巷组合观测值与L₁观测值提取测站大变形量的GPS单历元变形监测方法。充分利用变形监测点已知以及模糊度之间的线性相关性等特点,通过ARCE算法对测站先验坐标计算出的部分宽巷模糊度进行±1周的搜索,正确固定所有宽巷模糊度后提取监测点粗略变形量,再利用L₁观测值进一步提取剩余变形量。通过实例验证,本方法有效、可靠,在变形量较大的情况下能取得很好的效果。     

长距离单历元非差网络RTK方法

研究长距离网络RTK参考站整周模糊度单历元解算算法和区域误差非差改正数的计算方法,并介绍流动站整周模糊度的单历元解算方法,最后使用实测数据进行算法实验。实验表明,该方法可以利用非差误差改正数实现长距离网络RTK流动站的单历元cm级定位。     

根据地质记录恢复渐新世和中新世不同时期环境空间特征及其意义

已有工作对地质环境指标空间分布特征的研究揭示出,我国的环境在新生代期间经历了从近于东西向的带状格局向与现今相似的非带状格局的转变,代表了东亚地区重大的环境变化,但对这一转变的时间、空间变化的详细过程还缺少深入的认识。越来越多的证据显示,渐新世/中新世之交和中新世可能是这一环境变化最为关键的时期,因而有必要对渐新世和中新世内部不同时期的环境格局进行更详细的研究。近十年来,大量新的研究工作积累了更多的资料和证据,为进一步研究上述问题提供了新的可能。文章根据已有文献资料,对有明确环境意义和较可靠年代控制的地质记录进行了重新整理和分类,对渐新世和中新世不同时期的环境格局进行了详细的考察。研究显示,以内陆干旱为基本特征的非带状环境格局至少出现于中新世早期,与我国北方风尘堆积出现的时代具有一致性。     

Paleomagnetic dating of ironstone nodules (‘nuts’) from the Yowah opal field,central southern Queensland

To constrain the age of Australian opal formation, we have undertaken a paleomagnetic study of oxidised ironstone ‘nuts’ from Yowah, Queensland. Following standard methods, we have calculated a mean direction of declination D = 191.4°, inclination I = 61.7° (α₉₅ = 4.0°), indicating a paleomagnetic pole position at latitude λ_p = 71.3°S, longitude ?_p = 119.4°E (A₉₅ = 5.3°). The direction comprises both normal and reverse polarities that fail a reversal test most probably owing to contamination by small recent/present-day components. The mean direction should not be significantly affected. A chi-square comparison with paleomagnetic poles for dated Cenozoic rocks in eastern Australia, poles derived from the Global Moving Hotspot Reference Frame and the Cenozoic pole path for North America, appropriately transferred to Australian coordinates, yields a mean age estimate of 35 ± 7 Ma, i.e. late Eocene to early Oligocene. This is interpreted as the age of the ironstone formation, which places a maximum age for the formation of precious Yowah opal. This result confirms and tightens the age for the nearby Canaway weathered profile.     

The link between tectonics and sedimentation in asymmetric extensional basins: Inferences from the study of the Sarajevo-Zenica Basin

The coupled tectonic and depositional history of extensional basins is usually described in terms of stratigraphic sequences linked with the activity of normal faults. This depositional-kinematic interplay is less understood in basins bounded by major extensional detachments or normal fault systems associated with significant exhumation of footwalls. Of particular interest is the link between tectonics and sedimentation during the migration of normal faulting in time and space across the basin. One area where such coupled depositional-kinematic history can be optimally studied is the Late Oligocene - Miocene Sarajevo-Zenica Basin, located in the Dinarides Mountains of Bosnia and Herzegovina. This intra-montane basin recorded Oligocene – Pliocene sedimentation in an endemic and isolated lake environment. We use field kinematic and sedimentological mapping in outcrops correlated with existing local and regional studies to derive a high-resolution evolutionary model of the basin. The novel results demonstrate a close correlation between moments of normal faulting and high-order sedimentological cycles, while the overall extensional basin was filled by a largely uni-directional sediment supply from the neighbouring mountain chain. The migration in time and space of listric NE-dipping normal faults was associated with a gradual shift of the sedimentological environment. Transgressive-regressive cycles reflect sequential displacements on normal faults and their footwall exhumation, defining a new sedimentological model for such basins. This Early - Middle Miocene extension affected the central part of the Dinarides and was associated with the larger opening of the neighbouring Pannonian Basin. The extension was preceded and followed by two phases of contraction. The Oligocene - Early Miocene thrusting took place during the final stages of the Dinarides collision, while the post-Middle Miocene contraction is correlated with the regional indentation of the Adriatic continental unit. This latter phase inverted the extensional basin by reactivating the inherited basal listric detachment.     

实数编码加速遗传算法在GPS变形监测单历元求解中的应用

提出了一种基于实数编码加速遗传算法( RAGA)和模糊度直接计算的GPS变形监测单历元求解新算法.该方法以模糊度函数为适应度评价函数,采用自适应变化率的交叉算子和变异算子对监测点的坐标进行全局最优搜索.当监测点的坐标误差小于某一阈值时,采用直接计算法可固定双差模糊度,实现单历元解算.实例验证该算法具有快速、稳健和可靠等特点,具有一定的实际应用价值.     

“基因图谱”视角下闽台石器时代文化空间结构分析

聚落是识别区域文化景观同一性的重要指标。中国闽台石器时代文化因受区域环境的影响,呈现出与全国其他地区不同的文化特征。借用"文化基因"的概念,运用GIS技术对闽台石器时代文化遗址空间特征、文化特质和历史渊源进行分析。研究结果表明:闽台石器时代文化遗址在产生时间上具有继承性;在空间扩散、迁移及居住地空间选择上,闽台石器文化遗址都呈现了山岗、沿河流阶地和滨海分布模式,并经历了由点经线到面的扩散和迁移过程;在器具、技术工艺和作物类型等方面亦存在着广泛的相似性和共同性。石器遗址文化表明闽台具有相同的文化根基。     

中国金矿床:基于成矿时空的分类探讨

通过回顾近10年金矿床分类研究成果,总结了金矿床分类现状、存在的主要问题及其原因.认为金矿床分类应包括两个层面:一是理论分类,相当于过去所说的成因分类;二是应用分类,相当于矿床的工业分类.提出基于成矿时代(时间)-成矿环境(空间)为坐标系的新的理论分类方案.将内生金矿床划分为6种理论类型,即裂谷型(拉张期)、俯冲造山型(俯冲期)、碰撞造山型(碰撞期)、伸展造山型(伸展期)、板内(非造山型)("稳定"期)和过渡-叠加-复合型.将含金地质体的性质(种类)或矿床的突出产出特点作为划分金矿床应用类型的准则.对近8 000个金矿床的统计分析表明,石英脉型、(破碎)蚀变岩型、角砾岩型、斑岩型、微细浸染型(卡林-类卡林型)、(次)火山岩型(低硫、高硫)、夕卡岩型、(浅变质)沉积(碎屑)岩型、蛇绿岩(套)型(基性-超基性岩型)、红土(铁帽)型、(砂)砾岩型等11种金矿床类型是最常见、最重要的应用类型.讨论了新矿床分类方案的理论与实践意义及其在应用中应注意的问题.     

滇西点苍山-哀牢山变质岩系变质时限研究

点苍山-哀牢山变质带沿红河-哀牢山走滑剪切带呈北西-南东向展布,其主体由下元古界苍山群和哀牢山群深变质岩系组成,是滇西最显著的带状变质带之一。点苍山-哀牢山变质带的变质时限和山脉隆升时限由于缺乏精确年代学数据制约,一直存在不同认识。本文选取点苍山花岗闪长质糜棱岩（DCS-1）,哀牢山墨江-元江段黑云母花岗闪长质片麻岩（SM07-1）和其侵位的同变形花岗岩脉（SM07-3）以及元江县城西北山前花岗质片麻岩（YJ）作为研究对象,并挑选出锆石颗粒（SM07-3）、黑云母（SM07-1-Bi,SM07-3-Bi）、白云母（SM07-1-Ms）、钾长石(DCS-1-Kf, SM07-3-Kf)和斜长石（YJ-Pl）以及基质（YJ-ma）进行精确年代学测试。花岗岩脉颗粒锆石U-Pb SHRIMP 加权平均年龄为30.8±0.3Ma（SM07-3, MSWD=3.27）;其它单矿物激光⁴⁰Ar/³⁹Ar等时线年龄分别为13.1±1.5Ma (DCS-1-Kf, MSWD=2.9)、22.3±0.9Ma (SM07-1-Ms, MSWD=1.7)、21.9±0.7Ma (SM07-1-Bi, MSWD=1.3)、21.3±0.7Ma (SM07-3-Kf, MSWD=1.2)、22.7±0.8Ma (SM07-3-Bi, MSWD=2.4)、19.8±1.6Ma (YJ-ma, MSWD=19)和21.57±0.38Ma (YJ-Pl, MSWD=1.5)。结合区域地质背景、地质演化、野外观察和年代学资料,本文研究认为点苍山-哀牢山变质带的峰期变质变形时间为30Ma左右,此时山脉已开始隆升,在约20Ma和13Ma山脉分别经历一期构造热事件作用,揭示山脉经历快速隆升和冷却过程。     

青海扎陵湖和鄂陵湖盆地第四纪河湖相地层研究

通过对扎陵湖和鄂陵湖沿岸的湖积阶地中湖相沉积的野外地质调查和实测剖面,对分布于盆地内的第四纪早更新世-全新世湖相地层进行了详细的研究和划分、重新厘定了该区第四纪岩石地层单元,确立了生物地层和年代地层序列.建立了青海东南部地区第四纪早更新世-全新世湖相地层单位-黄河源群(QH),黄河源群是由第四系下更新统野生沟组(Qp~1γ)、中更新统鄂陵湖组(Qp~2e)、上更新统大野马岭组(Qp~3d)和全新统黑河乡组(Qhh)等4个组组成.为青藏高原湖泊演化、气候变化、古地理变迁研究,以及第四纪地层的划分与对比等提供了新资料.