Decodification of Earth Evolution in Deep-Time

In the new era of earth system science in conjunction with the digital revolution,new platforms and programs are required for facilitating the utilization of geoscience data,especially to improve the integration of structured data with unstructured data for solving complex problems.Big data is not just matter of size but most importantly how easily and effectively it can be used.A major goal is to facilitate a move from traditional scientific approaches to a more modern approach that involves big data analytics.

“Deep-time Digital Basin” Based on Big Data and Artificial Intelligence

1 Introduction Information technology has been playing an ever-increasing role in geoscience.Sphisicated database platforms are essential for geological data storage,analysis and exchange of Big Data(Feblowitz,2013;Zhang et al.,2016;Teng et al.,2016;Tian and Li,2018).The United States has built an information-sharing platform for state-owned scientific data as a national strategy.

Review on status of groundwater database and application prospect in deep-time digital earth plan

Groundwater is an important water resource.The total amount of active groundwater in a hydrological cycle is about 3.5 times that of the total amount of surface water.The information in the deep groundwater records the material exchange and dynamics in the earth’s evolution,which is an important aspect of the Deep-Time Digital Earth(DDE)plan.In recent years,scientists have discussed the distribution of transboundary aquifers and the environmental significance of groundwater resources through groundwater databases established by international organizations,such as the Global Groundwater Information System and the chronicles consortium,and national institutes,such as national geological surveys.The application of the groundwater database in the DDE plan,however,has been limited by the management,interactivity,and monitoring method of the groundwater data.The ability to further integrate data that are private and scattered across research institutions and individuals,while establishing an open,unified,and shared groundwater data platform,is essential to enhance our understanding of groundwater,ranging from shallow to deep water,which is a goal of the DDE plan.In this study,we introduced the current situation of groundwater database operations in domestic and international research and provided frontier research with groundwater big data.Considering the related objectives of the DDE plan and the limitations of existing groundwater databases,we proposed an improvement plan and new prospects for applying groundwater databases in the research of the deep earth.

Sedimentological/Palaeogeographic Data as Fundamental Building Blocks of the DDE Project:Critical Underpinning of Reconstructing Deep-time Earth Systems

1 Introduction Sedimentary rocks archive important information for understanding how the earth system operates and how life and environments have evolved through earth history.Properly identifying characteristics of sedimentary rocks,along with the subsequent interpretation of depositional processes and sedimentary environments in a basin or locality.

Ferrimagnetic Minerals in Red Paleosols of Pleistocene Epoch, Eastern China

The type, grain size and origin of ferrimagnetic minerals separated from red paleosols of Pleistocene Epoch (Q\-2) in eastern China, were studied by using mineral magnetic measurement, X\|ray powder diffraction and electron microscopy. Results showed that the iron oxides in red paleosols were composed of hematite (α\|Fe\-2O\-3), maghemite (γ\|Fe\-2O\-3) and goethite(α\|FeOOH). Mineral magnetic parameters and X\|ray diffraction patterns indicated that maghemite was the dominant remanence carrier in red paleosols, which is characterized by superparamagnetic (SP) and stable single domain (SSD) grains. The variations of magnetic susceptibility (χ), anhysteretic magnetic susceptibility (χ\-\{ARM\}) and saturation isothermal remanent magnetization (SIRM) for red paleosols following heating to various temperatures showed two peak values at 700℃ and 900℃. The spherulitic magnetic particles measuring \{250-1000\}μm in diameter in red paleosols were separated by the magnetic separation method, indicating that these magnetic particles were an assemblage of superparamagnetic and stable single domain ferrimagnetic grains. It is suggested that the ferrimagnetic minerals of red paleosols be a pedogenic ferrimagnetic component under high temperature and high humid conditions in the Pleistocene Epoch (Q\-2). It is concluded that the magnetism characteristics of red paleosols can be used to evaluate the environmental changes of Quaternary in eastern China.

PALEOSOLS OF SANDY LANDS AND ENVIRONMENTAL CHANGES IN THE WESTERN PART OF NORTHEAST PLAIN OF CHINA WESTERN DURING HOLOCENE

Two-three paleosol layers were formed in the western part of the Northeast Plain. China during Holocene. These paleosol layers interlaid with eolian fine sand layers. Dated by 14C dating. archeology and TL and analyzed by statistics.the formation periods of paleosols are divided from the results. The periods are 11, 000- 7000 5500-4500. 3500- 2800 and 1400- 1000 a B. P. respectively.According to the spore-pollen compositions in more than ten sand dune paleosol profiles, it is discovered th.t there is little spore-pollen in the sand layers and a little spore-pollen in the paleosol layers. The spore-pollen compositions in the paleosols are simple. mainly Artemisia (50% - 70%) and Chenopodiaceae. In the paleosols of 11,000 - 7000 a B. P.. the spore-pollen composition is Artemisia-Rubiaceaechenopodiaceae. The contents of Ephedra pollen in the lower and upper parts of the layer are less than that in the middle part. In the paleosols of 5500- 4500 a B. P.,the spore-pollen composition is Artem isal - Chenopod iaceae - Melilotus. There is some Salix sp. and Betula sp. pollen in the lower part of the layer and some Ephedra pollen in the upper part. In the paleosols of 3500- 2800 a B. P.. the spore-pollen composition is Artemisia Chenopodiaceae - Rubiaceae. There are som e Kochia and Baryaceae. In the paleosols of 1400-1000 a B. P., the spore-pollen composition is also Artemisia-Chjenopod tao eae - Rubiaceae. There is a little pine pollen. The grain size of paleosol is relatively coarse, but still finer than that of eolian sand and becomes coarser from the bottom to the top of the profile. This fact reflects that the weathering environments during the paleosol formation periods were wetter than that during the eolian periods and became dryer from middle to late Holocene.

PALEOSOLS AND THEIR REFLECTION OF THE ENVIRONMENTAL CHANGES IN THE NORTHEAST REGION OF THE QINGHAI－XIZANG PLATEAU

Based on field investigations,laboratory analyses and 14C dating,this paper discusses the laws of the formation and development of the paleosols in the northeast region of the Qinghai-Xizang Plateau since Late Pleistocene.The authors reconstruct basic conditions of climate,vegetation,soil and natural zones during the three periods in which the paleosols were formed,i.e.the last interglacial of the Late Pleistocene,warm stage of Late Glacial and the Optimum of Holocene.Finally,this paper discusses the relationship between the paleosols and the uplift of the Qinghai-Xizang Plateau.

Deep-time Paleogeographic Reconstruction Based on Database:Taking the South China T. approximatus Biozone(Early Ordovician) as an Example

Paleogeography is a discipline that studies spatial distribution and evolutionary characteristics of geographic objects in earth history(Feng,2003;Feng et al.,2012).It focuses on the sediments,organisms and environmental proxies,most of which are preserved in the rocks.However,a large amount of this geological and biological information was no longer preserved after the geological process of burial.

Paleosols from North Part of Barlad City （Romania）

The loess deposits comprise several paleosol layers reflecting alternation of drier and wetter climate during Quaternary. Such a situation occurs in north of Barlad, on The Sohodau＇s Hill. Morphological study of the quarry paleosols from north of Barlad was accomplished based on field observations and macroscopic physic-chemical results. Three levels of paleosols with variable thickness were determined. These three fossils layers are interbedded by four loess deposits. The physical-chimical data provide important information for the paleosol genesis and depositional/climatic environments. The carbon content and C/N ratio indicate the strength of pedogenesis in the Pleistocene and trends of biomass accumulation.

Analysis of Post-Burial Soil Developments of Pre-AD 79 Roman Paleosols near Pompeii(Italy)

The AD 79 eruption of Somma-Vesuvius completely buried the ancient landscape around Pompeii (Italy) to some extent conserving the pre-AD 79 Roman paleosols of the Sarno River plain. To estimate potential post-burial soil developments of these paleosols detailed soil liquid and solid phase analysis were carried out. Firstly, an in-situ soil hydrological monitoring was conducted within a pre-AD 79 paleosol in natural undisturbed stratification. The results show that soil water flow and nutrient transport from the overlying volcanic deposits into the pre-AD 79 paleosol take place. Secondly, to estimate their influence on the paleosol’s mineral soil properties, the solid phase of four pre-AD 79 paleosols and associated modern unburied soils were analysed and compared. By combining the data from the soil liquid and solid phase analysis, potential post-burial changes in the paleosols were estimated. Finally, a rise of the mean groundwater table was determined since AD 79. This distinguishes the Sarno River plain into two different zones of post-burial soil developments: 1) lower altitudes where formerly terrestrial paleosols are now influenced by groundwater dynamics and 2) higher altitudes where the paleosols are still part of the vadose zone and rather influenced by infiltration water or interflow. Thus, the mechanism of potential post-burial soil development being active in the pre-AD 79 paleosols is not uniform for the entire Sarno River plain but strongly depends on the paleotopographic situation.

黄土-古土壤互层对土壤水分运移及土体微结构的影响

黄土地区地质灾害问题的发生大多与水在黄土中的入渗有关,而马兰黄土-古土壤互层结构对土壤水分入渗规律的影响显著。为揭示古土壤阻滞作用下黄土水分运移规律及其对黄土体微结构的影响,为黄土地区工程实践提供理论基础,该研究以陕西省泾阳县南塬的黄土为研究对象,采用土柱模型进行水分入渗试验,研究黄土-古土壤互层条件下土壤水分运移规律。在此基础上,通过微结构测试、分形维数和概率熵等指标的计算,分析黄土-古土壤互层条件下土壤水分运移对黄土微结构的影响。结果表明:古土壤层的透水性弱,湿润锋抵达黄土与古土壤界面处产生瞬态滞水,且随着入渗强度增加滞水时间增加;古土壤层影响下黄土与古土壤界面处的滞水会导致孔隙结构相互连通,孔隙空间平均增加4.13%,孔隙方向概率熵平均减少0.029,分形维数平均减小0.076,即古土壤层的阻水作用使得界面处黄土的孔隙空间增大,孔隙排列有序,孔隙形态规则。研究结果为黄土地区的工程建设和生态环境保护提供科学支撑。

古土壤层间富水对黄土场地湿陷性的影响

黄土地层中往往交替分布着多层红色古土壤层,由于其硬度相对较高,遇水不易湿陷,对黄土地层湿陷量的测量结果有很大的影响。然而,对于古土壤对湿陷量的控制作用目前还缺乏相关研究,导致对湿陷地层湿陷量的科学取舍缺乏理论依据。为此该文统计了黄土高原区的浸水试验结果,分析了不同区域湿陷量室内外差异特征,并以西安地区两个试验场地的大型浸水试验为研究对象,进行了不同试验条件下土体中水分的扩散、含水率的变化、土压力变化以及累计湿陷量等测量工作。最终结果表明,古土壤层的存在阻碍湿陷进程,在阻止水分下渗的同时,阻碍深部地层湿陷量传递至地表,使得湿陷量实测值与计算值之间的差异与古土壤层数呈现正相关的趋势。该文将为普遍存在古土壤的黄土地层自重湿陷机理的研究提供参考。

黄土高原古气候变化定量重建的新进展

中国黄土-红黏土沉积是可与深海沉积媲美的陆相沉积载体,记录了晚新生代东亚大陆气候环境变化历史。基于中国黄土的多种理化指标,重建了黄土高原地区构造-千年尺度东亚季风变化历史,为探讨区域与全球气候的联系提供了关键证据。近年来,黄土高原古气候变化研究逐步从定性描述拓展到定量重建,本文旨在回顾基于中国黄土定量重建古温度和古降雨变化取得的重要进展。首先,梳理了古气候要素定量重建的指标和方法,古温度重建指标包括植硅体、碳酸盐耦合同位素、微生物脂类代用指标等;古降水变化敏感指标包括磁化率、白云石/方解石含量、生物微钙体Sr/Ca比值、有机碳同位素以及^(10)Be等。然后,汇总了典型黄土剖面定量重建的古气候变化序列,分别从构造、轨道及千年时间尺度上探讨了古温度和古降雨的变化特征。结果表明,基于生标重建的不同时间跨度的土壤古温度变化序列,在冰期—间冰期尺度上的波动特征基本一致,但在冰盛期—冰消期时段出现了增温超前现象,说明陆地植被对土壤温度变化有重要调制作用。然而,不同指标重建的降水变化幅度差异较大,主导周期也存在差异,说明定量重建降水变化仍有较大挑战。最后,简要总结了黄土高原古气候定量重建存在的问题,明确了区分温度和降水季节性变化的重要性,指出加强地质记录与模拟结果的对比同化,将有助深化对多尺度季风变化动力学的理解。

云南涛源盆地古砂脉及其代表的古地震事件

根据野外地质调查结果和地层测年数据,分析涛源盆地上部地层中的古砂脉及其代表的古地震事件。涛源至下力农东西长7 km的范围内集中分布十余处古砂脉,砂脉及砂流堆积呈蘑菇状、伞状、囊状和歪斜的水杯状,砂流堆积规模大,分布广,暗示该区域发生过强烈的喷砂冒水事件。砂流堆积宽数米,厚数十厘米至1 m左右,最大堆积宽度和厚度分别为8 m和1.0~1.5 m;砂脉长1.0~4.5 m,直径为0.25~0.35 m,最大宽度为0.8 m。地面以下1.5~3.0 m深度普遍发育连续性较好的古土壤层,代表砂脉形成时期的地表面。这些砂脉及砂流堆积普遍赋存在古土壤层的上下部位。据古土壤层顶部和砂流堆积上覆地层底部的14C测年结果,推测形成砂脉的古地震事件时间为13030±40~12120±40 aBP,震级大于7级。程海-宾川断裂为晚第四纪强烈活动断裂,并引发此次涛源大地震。

陕西渭北晚更新世黄土-古土壤结合水膜厚度的试验研究

为深入剖析黄土与古土壤工程性质的影响因素,以陕西渭北晚更新世黄土与古土壤为研究对象,基于核磁共振、比表面积测试并结合理论分析对结合水膜厚度进行研究。试验结果显示:黄土与古土壤的结合水膜厚度存在明显差异,黄土的结合水膜厚度明显大于古土壤,原因在于古土壤孔隙体积及孔径小于黄土,而古土壤中高价阳离子含量大于黄土,同时古土壤颗粒表面分布铁锰质薄膜,其亲水性较弱。分析结合水膜与黄土湿陷性、回弹变形等工程特性间的关系,发现黄土-古土壤的湿陷性随结合水膜厚度的增大而增强,随结合水膜厚度的减小而减弱,结合水膜厚度与卸荷变形系数呈正相关关系。综合分析说明,高价阳离子含量、颗粒表面特性,及孔隙性的不同造成了黄土与古土壤结合水膜厚度的差异,从而导致黄土与古土壤的湿陷性等工程性质有显著区别。

黄土-古土壤饱和渗透性与孔隙分布特征关系研究

由于沉积环境的差异,古土壤较上覆黄土致密,其饱和渗透系数应低于黄土,但试验结果却显示二者的饱和渗透系数相近。为揭示这一现象的机理,在陕西泾阳南黄土塬开挖33m的探井,沿井壁按1m间距取黄土和古土壤原状试样,进行变水头渗透试验,测定试样的饱和渗透系数。同时用压汞试验(mercury intrusion porosimetry,MIP)及扫描电镜(scanning electron microscope,SEM)测试分别获取试样的孔隙分布曲线和微观结构图像,以分析黄土-古土壤饱和渗透性与孔隙分布特征的关系。结果表明:(1)黄土-古土壤地层的饱和渗透系数整体上沿深度方向规律性减小,但相邻黄土和古土壤层的饱和渗透系数无明显差异;(2)MIP及SEM测试结果表明,黄土结构均匀、孔隙大小较为一致,而古土壤具有不均匀的团块-裂隙结构,虽然团块内部较黄土致密,但团块间存在裂隙;(3)饱和渗透系数的大小取决于透水孔隙的体积分数,其中黄土的透水孔隙主要为较大孔隙(孔径>2μm),而古土壤的透水孔隙主要为团块间的微裂隙,虽然二者渗透系数相近,但渗透机理完全不同。为研究黄土与古土壤的孔隙分布特性和解决黄土区工程建设中的问题提供了理论依据。

不同纬度黄土-古土壤赤铁矿含量差异及其气候指示意义——基于漫反射光谱和色度方法

在全球变暖的背景下,北极和第三极(青藏高原)的增温幅度高于世界上其他地区,其增温幅度和机制并不明晰,因此有必要开展不同时间尺度、不同气候记录载体的研究。利用赤铁矿研究末次间冰期-末次冰期的增温效应,使用漫反射光谱和色度方法量化俄罗斯西伯利亚、中国黄土高原西峰和中国川西高原甘孜3个沉积连续的黄土-古土壤序列中的赤铁矿,揭示其蕴含的气候信息。研究结果显示:(1)漫反射光谱和色度方法相结合是定量赤铁矿的有效方法。(2)在大空间尺度中,赤铁矿主要受控于温度而非降水。(3)在末次间冰期和末次冰期旋回时期,较高纬度气温变化幅度大于较低纬度气温变化幅度。不同纬度的气温“轨道尺度较差”可能是轨道尺度太阳辐射差异和年内太阳辐射差异的综合体现。

淮河流域颍河上游河谷沉积物物源分析

通过详细的野外考察,在淮河流域颍河上游的河谷地段见到具有典型代表性的完整沉积剖面,进一步对其进行野外宏观分层描述并每隔2 cm进行高分辨率采样,带回实验室进行分析。采用粒度端元分析手段,分析了地层剖面的物源问题。分析结果表明:本区黄土物源和黄土高原典型黄土有所不同,区域东北风作用下近源的风沙流沉积物占了相当份额;依据粒度端元分析,沉积动力组分主要由3部分组成,分别代表了风化成壤改造作用下的产物、东亚冬季风作用下从西北荒漠搬运而来的粉尘物质以及东北风作用下从近源搬运而来的黄泛沉积物;在不同的时期,沉积作用动力强弱有明显的变化,表明了全新世以来区域季风气候对全球气候变化的响应过程。研究对淮河流域颍河上游局部河谷沉积物物源组成特点进行了量化分析,这对于深入理解淮河上游沉积物物源及全新世以来其季风作用下的地表过程演变特征具有重要的科学意义。

淮河支流汝河全新世古洪水沉积序列粒度指示的地表过程

【目的和方法】为了深入理解淮河流域全新世环境与地表过程演变,通过对淮河流域详细的野外调查,在汝河上游诸市乡段一级河流阶地前沿发现了夹有多层古洪水滞流沉积层的全新世黄土土壤沉积物地层剖面。对该剖面进行详细观察测量,地层划分和分层采样,在实验室进行多种指标分析研究。在前期沉积学性质研究和年代测定的基础上,应用端元分析方法进行粒度成分解析,深入分析古洪水沉积物序列的物源及其沉积学特征变化规律。【结果】采用非参数法从沉积序列中解析出具有不同物源和沉积动力学意义的4个端元组分。各土壤沉积物地层单元中除了现代洪水沉积层和河漫滩相细沙层外,其余层次都显示出多端元组分混合叠加的特点。【结论】结合野外宏观特征及其理化性质综合分析,可知其端元1组分代表西北季风沙尘暴远源风成沉积物及其风化成壤改造的产物,端元2组分代表了东北风吹扬黄泛平原松散沉积物沙尘暴的近源沉积物,端元3组分代表了河流洪水悬移质泥沙在高水位滞流环境条件下的沉积物,端元4组分为河流在河槽之内水动力作用下河漫滩冲积物。表明通过对全样粒度进行端元解析,能够更清晰地反映出汝河流域多元化的沉积动力特点。

黄土-古土壤地层深竖井受力变形特征研究

研究目的:为准确认识黄土-古土壤地层条件下的深竖井受力变形特征,以53.5 m深圆形竖井工程为依托,开展竖井侧向土压力、变形、结构内力及周边地层的竖直和水平向变形的系统监测。研究结论:(1)黄土-古土壤地层深竖井开挖过程中,井壁结构整体变形较小,水平变形“先挤出后收敛”,竖向变形“先下沉后隆起”,竖井开挖至设计深度后,15~30 d进入结构受力变形稳定阶段;(2)竖井井壁收敛变形、侧向土压力和结构内力在深度方向上存在拐点,出现在0.5~0.7倍竖井设计深度处,其受力变形指标和土层性质存在良好的对应关系,在古土壤范围内,井壁变形量和土压力明显减小,约为邻近深度处黄土层的40%~50%,古土壤的存在,限制了竖井变形和土压力的发展;(3)黄土-古土壤地层深竖井井壁结构侧向土压力与静止土压力和主动土压力有显著差异,在0~12 m深度范围内,侧向土压力接近静止土压力;12~28 m范围内,侧向土压力接近主动土压力;28~48 m范围内,侧向土压力均小于主动土压力,为其35%~65%;(4)本研究成果可为相近地层条件下深竖井的土压力计算和支护结构设计提供参考依据。