Ephemeral rollover points and clinothem evolution in the modern Po Delta based on repeated bathymetric surveys

Reconstructions of ancient delta systems rely typically on a two-dimensional (2D) view of prograding clinothems but may miss their three-dimensional (3D) stratigraphic complexity which can, instead, be best documented on modern delta systems by integrating high-resolution geophysical data, historical cartography, core data and geomorphological reconstructions offshore. We quantitatively compare three precisely positioned, high-resolution multi-beam bathymetry maps in the delta front and pro delta sectors (0.3 to 10 m water depth) of Po di Pila, the most active of the modern Po Delta five branches. By investigating the detailed morphology of the prograding modern Po Delta, we shed new light on the mechanisms that control the topset to foreset transition in clinothems and show the temporal and spatial complexity of a delta and its pro delta slope, under the impact of oceanographic processes. This study documents the ephemeral nature of the rollover point at the transition between sandy topset (fluvial, delta plain to mouth-bar) and muddy seaward-dipping foreset deposits advancing, in this case, in >20 m of water depth. Three multibeam surveys, acquired between 2013 and 2016, document the complexity in space and time of the topset and foreset regions and their related morphology, a diagnostic feature that could not be appreciated using solely 2D, even very high-resolution, seismic profiles. In addition, the comparison of bathymetric surveys gathered with one-year lapses shows the migration of subaqueous sand dunes on the clinothem topset, the formation of ephemeral cut-and-fill features at the rollover point (few m below mean sea level), the presence of collapse depressions derived by sagging of sediments and fluid expulsion (possibly induced by storm waves) on the foreset, and splays of sand likely reflecting gravity flows on the lower foreset. Though the modern Po Delta is anthropogenic in many respects, its subaqueous clinothem can be studied as a scale model for ancient clinothems that are less resolved geometrically and far less constrained chronologically.     

Upslope-climbing shelf-edge clinoforms and the stepwise evolution of the northern European glaciation (lower Pleistocene Eridanos Delta system,U.K. North Sea): When sediment supply overwhelms accommodation

Clinoforms are basinward-dipping and accreting palaeo-bathymetric profiles that record palaeo-environmental conditions and processes; thus, clinothems represent natural palaeo-archives. Here, we document shelf-edge scale clinoform sets which prograded through the entire width of an epicontinental marine basin (ca. 400 km), eventually encroaching onto the opposite basin flank, where they started to prograde upslope and landward, in defiance of gravity (“upslope-climbing clinoforms”). The giant westward-prograding Eridanos muddy shelf-edge clinothem originated from the Baltic hinterland in the Oligocene and achieved maximum regression in the Early Pleistocene, on the UK Central Graben (CG) and Mid North Sea High (MNSH), after crossing the whole North Sea mesopelagic depocentre and causing near complete basin infill. Here we integrate well and seismic data through the MNSH and CG and examine the Eridanos final heyday and demise, identifying five clinothem complexes (A1, A2, A3, B and C) and six depositional sequence boundaries (SB1 to SB6) in the Miocene-Recent section. Tectonic and climatic events drove the recent evolution of this system. Early Pleistocene climate cooling, in particular, resulted in a stepwise increase in sediment supply. This climaxed in the earliest Calabrian, following a likely Eburonian eustatic fall (=SB3) when the Eridanos clastic wedge was restructured from a 100–300 m thick compound shelf-edge and delta system to a “hybrid” shelf-edge delta at sequence boundary SB3 (ca. 1.75 Ma). In the ca. 40 kyr that followed SB3, a progradation rate peak (>1,000 m/kyr) is associated with clinoforms starting to accrete upslope, onto the east-dipping slope between CG and MNSH. This “upslope-climbing clinoform” phase was quickly followed by the maximum regression and final retreat of the Eridanos system in the Early Calabrian (=SB4), likely as the result of climate-driven changes in the Baltic hinterland and/or delta auto-retreat. To our knowledge, this contributions represents the first documentation of “upslope-climbing clinoforms” recorded in the stratigraphic record.     

Paleogene evolution and demise of the proto‐Paratethys Sea in Central Asia (Tarim and Tajik basins): Role of intensified tectonic activity at ca. 41 Ma

The proto‐Paratethys Sea covered a vast area extending from the Mediterranean Tethys to the Tarim Basin in western China during Cretaceous and early Paleogene. Climate modelling and proxy studies suggest that Asian aridification has been governed by westerly moisture modulated by fluctuations of the proto‐Paratethys Sea. Transgressive and regressive episodes of the proto‐Paratethys Sea have been previously recognized but their timing, extent and depositional environments remain poorly constrained. This hampers understanding of their driving mechanisms (tectonic and/or eustatic) and their contribution to Asian aridification. Here, we present a new chronostratigraphic framework based on biostratigraphy and magnetostratigraphy as well as a detailed palaeoenvironmental analysis for the Paleogene proto‐Paratethys Sea incursions in the Tajik and Tarim basins. This enables us to identify the major drivers of marine fluctuations and their potential consequences on Asian aridification. A major regional restriction event, marked by the exceptionally thick (≤ 400 m) shelf evaporites is assigned a Danian‐Selandian age (ca. 63–59 Ma) in the Aertashi Formation. This is followed by the largest recorded proto‐Paratethys Sea incursion with a transgression estimated as early Thanetian (ca. 59–57 Ma) and a regression within the Ypresian (ca. 53–52 Ma), both within the Qimugen Formation. The transgression of the next incursion in the Kalatar and Wulagen formations is now constrained as early Lutetian (ca. 47–46 Ma), whereas its regression in the Bashibulake Formation is constrained as late Lutetian (ca. 41 Ma) and is associated with a drastic increase in both tectonic subsidence and basin infilling. The age of the final and least pronounced sea incursion restricted to the westernmost margin of the Tarim Basin is assigned as Bartonian–Priabonian (ca. 39.7–36.7 Ma). We interpret the long‐term westward retreat of the proto‐Paratethys Sea starting at ca. 41 Ma to be associated with far‐field tectonic effects of the Indo‐Asia collision and Pamir/Tibetan plateau uplift. Short‐term eustatic sea level transgressions are superimposed on this long‐term regression and seem coeval with the transgression events in the other northern Peri‐Tethyan sedimentary provinces for the 1st and 2nd sea incursions. However, the 3rd sea incursion is interpreted as related to tectonism. The transgressive and regressive intervals of the proto‐Paratethys Sea correlate well with the reported humid and arid phases, respectively in the Qaidam and Xining basins, thus demonstrating the role of the proto‐Paratethys Sea as an important moisture source for the Asian interior and its regression as a contributor to Asian aridification.     

Tracing clinothem geometry and sediment pathways in the prograding Holocene Po Delta system through integrated core stratigraphy

Though clinothem geometry represents a key control on fluid flow in reservoir modelling, tracing clinothem boundaries accurately is commonly limited by the lack of sufficiently precise outcrop or subsurface data. This study shows that in basin systems with strongly heterogeneous compositional signatures, the combination of bulk-sediment geochemistry and benthic foraminiferal distribution can help identify clinothem architecture and generate realistic models of 3D deltaic upbuilding and evolution. Middle-late Holocene deposits in the Po Delta area form an aggradational to progradational parasequence set that reveals the complex interaction of W–E Po Delta progradation, S-directed longshore currents (from Alpine rivers) and Apennines rivers supply. Unique catchment lithologies (ophiolite rocks and dolostones) were used to delineate basin-wide geochemical markers of sediment provenance (Cr and Mg) and to assess distinctive detrital signatures. The geochemical characterization of cored intervals across different components of the sediment routing system enabled a direct linkage between clinothem growth, transport pathways and provenance mixing to be established. On the other hand, abrupt microfaunal variations at clinothem boundaries were observed to reflect the palaeoenvironmental response to sharp changes in sediment flux and fluvial influence. This study documents the ability of an integrated geochemical and palaeoecological approach to delineate three distinct sources (Po, Alps and Apennines) that contributed to coastal progradation and to outline the otherwise lithologically cryptic geometries of clinothems that using conventional sedimentological methods it would be virtually impossible to restore.     

Along‐strike variability in shelf‐margin morphology and accretion pattern: An example from the northern margin of the South China Sea

Interplays among diachronous tectonism, uneven sediment supply, and local marine hydraulic processes make the northern margin of the South China Sea (SCS) an ideal location to investigate the complexity of along‐strike variability in shelf margins. This study examines shelf‐margin morphology, stratigraphy, and sedimentation from the northern SCS using multichannel seismic reflection profiles complemented with the data from commercial and ocean drilling sites. Analysis of seismic reflection profiles reveals three categories of shelf‐margin cross‐sectional profiles, the concave‐up, linear, and sigmoidal, according to which five margin sectors were recognized. Results show that these margin segments differ in relief, shelf‐edge trajectory, submarine canyon development, and long‐term accretion pattern. The westernmost margin sector, or the Yinggehai (YGH)‐western Qiongdongnan (QDN) margin, has appeared to be supply dominated since its commencement at ca. 10.5 Ma, which is characterized by well‐developed prograding clinoforms, low‐angle shelf‐edge trajectories, and an absence of canyons. Presence of concave‐up profiles is also suggestive of high sediment influx. In contrast, the eastern QDN margin was primarily regulated by local subsidence and faulting, leading to a stationary shelf‐edge migrating pattern and linear upper‐slope morphology. Densely distributed slope‐confined gullies indicate the margin’s disequilibrium and erosive nature. Further east, the Pearl River Mouth (PRM) margin formed much earlier (ca. 30 Ma) and experienced a more complicated accretion history, including three phases which were dominated by sequential marginal faulting (before ca. 30 Ma), basement structure (ca. 30–23 Ma), and sediment supply (ca. 23 Ma to the present). The overall sigmoidal morphology and truncated stratigraphy of this margin probably resulted from the sculpting of local marine processes, especially ocean currents and internal waves. The exception of the central PRM margin where concave‐up profiles develop is mainly related to canyon erosion. Overall, this study highlights the vital role of local forcing factors in controlling along‐margin variations and determining the final fates of different margin segments. A comparison between the northern SCS and other well‐established examples reveals that concave‐upward shelf‐margin shapes, which are usually associated with high sediment supply, little influence from hydraulic regimes, or sometimes, high degree of canyon development, may be an indicator of good reservoir potential beyond the shelf edge.     

Private property restitution: the geographical consequences of official government policies in Central and Eastern Europe

The restitution of private property has been a widespread and controversial part of the post-socialist transformation in Central and Eastern Europe, raising issues about social justice and the responsibilities of national governments for the actions of their predecessors. This paper reviews the implementation of the restitution process in the countries of the region and assesses the impact on the social and economic landscape. The policy has been most extensive in Germany and most controversial in Poland, and the impacts in these two countries are considered in detail. The results show that everywhere restitution has resulted in winners and losers, with some claimants having long-lost property returned, but too often at the cost of residents losing their homes. However, an important benefit, notably in Germany's New Bundesländer, has been the introduction of much-needed new investment into the urban fabric of towns and cities, although the landscape impacts elsewhere have been less significant. Nevertheless, throughout Central and Eastern Europe restitution policies have helped governments to come to terms with a difficult aspect of the past and move forward.     

近130年来中亚干旱区典型流域气温变化及其影响因子

利用中亚干旱区5 大主要典型流域代表性气象站点近130 年逐月实测气温数据,结合线性趋势、Mann-Kenndall 非参数检验和小波分析等方法,研究了各流域气温的多时间尺度特征,并探讨了引起气温变化的可能因素。研究发现,在近130 年来中亚干旱区各主要流域（除阿姆河外）年均气温均呈上升趋势,增温趋势高于全球和周边地区,中亚干旱区气温对全球变化的响应比其他地区更加明显。20 世纪80 年代之后更加明显,并表现出明显的多时间尺度周期振荡特征,这主要是自然外强迫动力作用、气候系统内部变化和人类活动相互叠加的结果,亚洲极涡强度减弱和面积缩小对主要流域气温变化的作用明显,其次是北半球环状模（北极涛动）和青藏高原的影响,而CO₂引起的温室气体增温效应在中亚干旱区也不容忽视。气温表现出与布吕克纳周期（BC）、太平洋年代际涛动（PDO）和准2~3 年振荡周期（TBO）等有关的显著周期,可以证实中亚干旱区气温变化与大气环流、海温和太阳活动等密切相关。     

大河三角洲河口海岸演化机理模型研究:(II)模型构建与实证

本文以z坐标下的三维斜压海洋动力学数值模式为基本模式原型,在整理渤海基本数据并诊断计算风生环流和热盐环流作为背景环流场基础上,初步建立了渤海海域动力环境数值模式。模式采用了经校正的Bagnold型方程来计算渤海底移质沉积物输运,悬移质计算则是取二维深度平均悬移质输运方程和河床变形方程,计算含沙量分布以及由悬移物引起的冲淤厚度。利用这种方法建立的沉积物输运模式,定量模拟了渤海沿岸和海底的沉积物输运方向和冲淤分布。模拟结果与通过多年实测水深估算获得的渤海海底沉积物的冲淤变化分布相比较,两者之间在基本结论上是比较一致的     

Acquisition of industrial enterprises and its relations with regional identity: The case of the beer industry in Central Europe

ABSTRACT

The development of globalisation has ushered in fundamental changes that have led to a break in the relationship between places of production and places of consumption, and sometimes a rejection of global products and corporations at the local level in accordance with neolocalism. The objective of the article is to examine the effect of regional identity on the local impacts of global processes by applying a multilevel analysis of the brewing industry, in which consumers are very sensitive to changes in the beer offered and can influence it, for example by putting pressure on representatives of restaurants. Beginning with extensive research on the international level, the authors point out the various impacts of brewery acquisitions in three Central European countries – Czechia, Poland and Slovakia – that differ regarding the role of beer in the identity of their inhabitants. Thereafter, they focus on two Czech beer brands, the production of which was relocated to other regions after acquisitions. Based on field studies in the regions of the brands’ original production, the authors find that both brands lost popularity among their original customers. They conclude that for Czech customers, the place of production may be an important factor when choosing a beer brand.     

Late holocene level fluctuations of the Lake Ilay in Jura,France: sediment and mollusc evidence and climatic implications

The level fluctuations of Lake Ilay, Jura (France) during the last three millennia are reconstructed from sedimentological and malacological analyses of a core that is well-dated by tree-ring, radiocarbon and pollen datings. Changes in sediment facies, in carbonate concretion assemblages and in mollusc assemblages highlight a major lowering phase atc. 1550 BP and minor lowering phases atc. 2800 BP and shortly before AD 1394. Rises in lake level developed during the early Subatlantic and betweenc. 1500 and 1000 BP. These data are in good agreement with other proxy data from higher European and American latitudes. These correlations support the climatic origin of the level fluctuations of the Lake Ilay during the late Holocene. They suggest that the mediaeval climatic optimum is centred rather in the early than the late Middle Age.     

The role of soil erosion and fluvial processes in the post-fallout redistribution of Chernobyl-derived caesium-137: a case study of the Lapki catchment, Central Russia

The central area of the Russian Plain received substantial amounts Cs-137 fallout as a result of the Chernobyl accident in 1986, with inventories exceeding 40 kBq m⁻² in many of the areas close to Chernobyl. Concern over the longer-term fate of this contamination has focused attention on the need to predict the post-fallout redistribution of the radiocaesium and, thus, future changes in the spatial distribution of contamination in the landscape. Since radiocaesium reaching the land surface as fallout is rapidly and strongly adsorbed by soil and sediment particles, any attempt to predict its post-fallout redistribution must focus on erosion and sediment delivery processes and must rely heavily on a knowledge of the geomorphological processes involved. This paper reports a detailed investigation of post-fallout Cs-137 redistribution in the 2.18-km² Lapki catchment in the Middle-Russian Upland, which has required consideration of soil erosion processes, sediment delivery pathways, sediment delivery ratios and sediment sinks. The time elapsed since the Chernobyl accident is currently insufficient to result in significant reduction of Cs-137 inventories in eroding areas, but areas of deposition on both the lower slopes and on the balka sides and bottoms are already marked by significant increases in Cs-137 inventories. The results obtained emphasise that any attempt to develop meaningful predictions of the longer-term redistribution of Chernobyl-derived Cs-137 fallout within the Russian Plain must be based on a sound and detailed understanding of the linkage between the slopes and the balka systems and the fate of sediment entering the balka systems.     

民族县域旅游发展定量综合评价——以黔东南苗族侗族自治州16个民族县域为例

自我国全面实施两部大开发战略以来,民族地区旅游发展取得了质的飞跃.通过检索研究文献发现,民族地区旅游发展已成为国内旅游理论界研究的一个稳定方向.然而实践表明:基于区域微观尺度的民族县域旅游发展优劣是衡量民族地区旅游可持续发展的重要标尺之一,因此对民族县域旅游发展进行科学评价,才能有的放矢地为民族地区旅游可持续发展制定出适宜策略.本文构建了民族县域旅游发展的资源--经济--环境综合评价指标体系,运用因子分析法和系统聚类分析法对黔东南苗族侗族自治州16个民族县域旅游发展进行了定量研究.研究结果表明:优势发展县域凯里(市)综合评价得分最高为1.510,显示出其作为黔东南州首府旅游发展及其经济社会发展的综合基础优势;极核发展县域雷山、镇远、施秉、黎平、从江和榕江旅游发展速度较快,逐渐成长为黔东南州旅游发展的核心民族县域;均衡发展县域锦屏、台江、剑河、黄平、麻江和丹寨发展潜力较大;滞后发展县域岑巩、三穗和天柱发展较为缓慢.上述结果揭示了民族县域旅游发展相似性和差异性的特点和规律,为民族县域旅游可持续发展研究提供了参考依据.     

Seismic geomorphology and origin of diagenetic geobodies in the Upper Cretaceous Chalk of the North Sea Basin (Danish Central Graben)

Kilometre‐scale geobodies of diagenetic origin have been documented for the first time in a high‐resolution 3D seismic survey of the Upper Cretaceous chalks of the Danish Central Graben, North Sea Basin. Based on detailed geochemical, petrographic and petrophysical analyses, it is demonstrated that the geobodies are of an open‐system diagenetic origin caused by ascending basin fluids guided by faults and stratigraphic heterogeneities. Increased amounts of porosity‐occluding cementation, contact cement and/or high‐density/high‐velocity minerals caused an impedance contrast that can be mapped in seismic data, and represent a hitherto unrecognized, third type of heterogeneity in the chalk deposits in addition to the well‐known sedimentological and structural features. The distribution of the diagenetic geobodies is controlled by porosity/permeability contrasts of stratigraphic origin, such as hardgrounds associated with formation tops, and the feeder fault systems. One of these, the Top Campanian Unconformity at the top of the Gorm Formation, is particularly effective and created a basin‐wide barrier separating low‐porosity chalk below from high‐porosity chalk above (a Regional Porosity Marker, RPM). It is in particular in this upper high‐porosity unit (Tor and Ekofisk Formations) that the diagenetic geobodies occur, delineated by “Stratigraphy Cross‐cutting Reflectors” (SCRs) of which eight different types have been distinguished. The geobodies have been interpreted as the result of: (i) escaping pore fluids due to top seal failure, followed by local mechanical compaction of high‐porous chalks, paired with (ii) ascension of basinal diagenetic fluids along fault systems that locally triggered cementation of calcite and dolomite within the chalk, causing increased contact cements and/or reducing porosity. The migration pathway of the fluids is marked by the SCRs, which are the outlines of high‐density bodies of chalk nested in highly porous chalks. This study, thus, provides new insights into the 3D relationship between fault systems, fluid migration and diagenesis in chalks and has important applications for basin modelling and reservoir characterization.     

黄河中下游泥沙通量变化规律

根据黄河中下游多个主要水文控制站50多年的实测资料,利用水文学、泥沙运动力学、河床演变学和经验统计相结合的分析方法,分析黄河中下游泥沙通量的变化规律。结果表明,黄河中下游泥沙通量递减的同时泥沙粒径变细,人为因素影响巨大;中下游泥沙通量变化具有阶段性、季节性和自相关性。黄河下游河道泥沙冲刷与淤积均具有上段变化大、下段变化小的特点,这是由河道下游上宽下窄、上陡下缓特征决定的;下游河道输沙能力影响因子中,河道水量尤其是汛期水量起主要作用。     

东南亚华人族群融入移入国主流社会的比较研究——以印尼与泰国作对比分析

东南亚是海外华人华侨社会历史最悠久、人口最多、经济角色十分突出的地区。总体上,华人华侨与所在国原住民和睦相处,已逐步融入主流社会,为当地社会进步做出了贡献。但由于各国历史发展不同,华人与所在国原住民融合程度大不相同。本文以印尼与泰国相比较,探讨华人与原住民融合状况,并从政治经济和社会文化因素等方面对造成悬殊差别的原因进行了分析     

广东省中心城市发展潜力分析与省域城镇空间发展

运用主成分分析法(PCA),在SPSS 13.0统计软件支持下,对广东省21个中心城市的发展潜力进行了测度,并将第一、第二和综合主成分按其得分水平进行了等级划分.结果表明:各主成分所代表的经济活力、农业发展水平和城市发展潜力,在省域范围内的地域分布具有不同的特征,且三者间差异较大.据此提出了有利于广东省城镇空间合理有序发展的几点启示.     

输沙量 、侵蚀量与泥沙输移比的流域尺度关系——以赣江流域为例

输沙量、侵蚀量与泥沙输移比的流域尺度转换研究是当前流域侵蚀产沙研究领域的前沿课题,旨在通过尺度转换理论将坡面小区试验研究成果转换到流域的更大范围。以赣江流域实测输沙量和计算侵蚀量与泥沙输移比数据为基础,探讨了该流域3个变量的流域尺度关系,进而研究分析了3个变量尺度转换的可能性。3个变量与流域面积的关系散点图和相关方程都反映了这3者与流域面积不存在明显的相关关系,相悖于前人反比关系的结论。文章还阐述了流域面积的内涵及输沙量、侵蚀量和输移比的影响因素与流域面积的关系,发现3个变量的影响因素与流域面积不存在尺度效应。由此推断在赣江流域输沙量、侵蚀量和泥沙输移比实现尺度转换存在的可能性不大。这一研究结论是否成立或是否具有普遍性意义还有待于更多流域的研究成果来进一步证实。     

Applicability evaluation of the SWIM at river basins of the black soil region in Northeast China: A case study of the upper and middle Wuyuer River basin

In this paper, we selected the middle and upper reaches of the Wuyuer River basin in the black soil region of Northeast China as the study area. We adopted the soil and water integrated model (SWIM) and evaluated the parameter sensitivity using partial correlation coefficient. We calibrated and validated our simulation results based on the daily runoff data from Yi’an hydrological station at the outlet of the river basin and the evaporation data recorded by various weather stations from 1961 to 1997. Following evaluation of the modeling data against the observed data, we present the applicability of SWIM in the river basin of the black soil region, and discuss the resulting errors and their probable causes. Results show that in the periods of calibration and validation, the Nash-Sutcliffe efficiency (NSE) coefficients of the monthly and daily runoffs were not less than 0.71 and 0.55, and the relative errors were less than 6.0%. Compared to daily runoffs, the simulation result of monthly runoffs was better. Additionally, the NSE coefficients of the potential monthly evaporation were not less than 0.81. Together, the results suggest that the calibrated SWIM can be utilized in various simulation analyses of runoffs on a monthly scale in the black soil region of Northeast China. On the contrary, the model had some limitations in simulating runoffs from snowmelt and frozen soil. Meanwhile, the stimulation data deviated from the measured data largely when applied to the years with spring and summer floods. The simulated annual runoffs were considerably higher than the measured data in the years with abrupt increases in annual precipitation. However, the model is capable of reproducing the changes in runoffs during flood seasons. In summary, this model can provide fundamental hydrological information for comprehensive management of the Wuyuer River basin water environment, and its application can be potentially extended to other river basins in the black soil region.     

废黄河沉积记录中来自不同河流物质的信息——基于重矿物与地球化学元素分析

在全新世时间尺度内,沉积记录主要受控于沉积物供给、输运和堆积过程等因素。对废黄河沉积记录的深入分析可以反演黄河南流夺淮过程中沉积物的“源”-“汇”关系。基于废黄河故道沉积记录中重矿物和地球化学元素特征,并结合与现代黄河沉积物的对比,揭示废黄河沉积记录中物质来源的信息。结果表明,废黄河故道沉积物中重矿物平均含量为0.19%,种类多达15余种,以稳定矿物为主,不同矿物的时空变化差异较大。废黄河故道泥质和砂质沉积物中,地球化学元素表现出明显的时空变化规律,随深度递增元素含量可分为降低、稳定和增加趋势。对比现代黄河沉积物,发现废黄河故道沉积物中稳定和极稳定矿物相对含量较高,泥质沉积物中更多地富集Zn,Ni,Al,Ba,Cu,Li,K等元素。这一差异性反映出其它不同河流物质补给而产生的影响,淮河沉积物中重矿物和地球化学元素的研究为该论断提供了佐证。