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1.
《Proceedings of the Geologists' Association. Geologists' Association》2021,132(5):605-619
Using outlines of ten geodiversity-related topics plus some related studies, this paper argues that geodiversity has contributed to many new insights, new avenues of research and new results. The ten topics are: Celebrating, Assessment and Measurement, Geosystem Services, Biodiversity, Geomaterials, Geotourism and Leisure, Geoheritage, National Geoconservation, World Heritage Sites and Global Geoparks, and Sustainability. It is concluded that geodiversity is a) a global, as well as regional/local concept, b) more than just related to biodiversity, important though that is, c) absolutely central to any relationship between the geology-related topics (‘Gs’). It is therefore argued that geodiversity is not a ‘redundant term’ as recently suggested but instead is a significant, multi-faceted and evolving, geoscientific paradigm. 相似文献
2.
《地学前缘(英文版)》2022,13(6):101436
Zircon is a widely-used heavy mineral in geochronological and geochemical research because it can extract important information to understand the history and genesis of rocks. Zircon has various types, and an accurate examination of zircon type is a prerequisite procedure before further analysis. Cathodoluminescence (CL) imaging is one of the most reliable ways to classify zircons. However, current CL image examination is conducted by manual work, which is time-consuming, bias-prone, and requires expertise. An automated and bias-free method for zircon classification is absent but necessary. To this end, deep convolutional neural networks (DCNNs) and transfer learning are applied in this study to classify the common types of zircons, i.e., igneous, metamorphic, and hydrothermal zircons. An atlas with over 4000 CL images of these three types of zircons is created, and three DCNNs are trained using these images. The results of this study indicate that the DCNNs can distinguish hydrothermal zircons from other zircons, as indicated by the highest accuracy of 100%. Although similar textures in igneous and metamorphic zircons pose great challenges for zircon classification, the DCNNs successfully classify 95% igneous and 92% metamorphic zircons. This study demonstrates the high accuracy of DCNNs in zircon classification and presents the great potentiality of deep learning techniques in numerous geoscientific disciplines. 相似文献
3.
Complex interplay between depositional and petrophysical environments in Holocene tidal carbonates (Al Ruwais,Qatar) 
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下载免费PDF全文 Sam Purkis John Rivers Christian J. Strohmenger Christopher Warren Ruqaiya Yousif Luis Ramirez Bernhard Riegl 《Sedimentology》2017,64(6):1646-1675
Carbonate rocks can be classified in terms of those properties relating to the pore system of lithified sediments, so‐called ‘petrophysical rock types’, or ‘depositional rock types’ which are categorized based on characteristics directly reflecting their original depositional environment. Whereas petrophysical rock types are typically used to identify and distribute rock bodies within a reservoir with similar flow characteristics, depositional rock types ignore pore types and capture sedimentary structures, lithology and fossils. Both classification systems are extensively used to describe reservoir rocks, but the degree of plurality between them remains poorly understood and is the motivation for this study. To examine the degree of congruency between the two classification schemes, a field assessment was conducted for a 175 km2 area situated offshore Al Ruwais, northern Qatar, encompassing depositional environments spanning supratidal, intertidal, shallow subtidal and open marine conditions. A total of 350 surficial sediment samples were collected along 24 shore‐normal transects. Each sample was assigned a ‘petrophysical rock type’ class based on analysis of sedimentary texture (grain size and sorting). ‘Depositional rock type’ classes, by contrast, were defined with reference to faunal content and, in turn, classes of mineralogy were delimited by weighting this content against the mineralogy of each faunal category. Of course, the samples studied correspond to unconsolidated sediments and not to indurated rocks. However, considering only primary porosity and permeability preservation, it is reasonable to assume that the classified sediments would become petrophysical rock types and depositional rock types when consolidated, following their primary grain size, sorting and grain type distribution. Therefore, the term ‘rock type’ is retained here for ease of terminology but, for clarity, these are sediment samples. The discrete samples were interpolated into continuous surfaces describing the distribution of depositional rock types, petrophysical rock types and mineralogy, and spatial correspondence between those surfaces was statistically evaluated. In order to link these parameters with environment of deposition, their correlation with water depth (as audited from airborne light detection and ranging) and ecological habitat (mapped from DigitalGlobe satellite imagery) was also assessed. The data reveal that spatial distributions of sedimentary faunal, petrographic and mineralogical properties do not show exactly congruent patterns. Other meaningful trends do exist, however. For example, the occurrence of certain depositional rock types is indicative of particular petrophysical rock types, and vice versa. Further, connections between petrophysical rock types and mineralogy are emphasized and offer insight as to how the evolution of matrix porosity might be predicted via diagenetic models tuned to specific sediment textures. Useful relationships are also identified between the occurrence of petrophysical rock types and depositional rock types, and both ecological habitat and water depth. The potential of such dualities is two‐fold. Firstly, they can be applied to more realistically distribute petrophysical rock types and depositional rock types by environment of deposition in reservoir models and, secondly, the use of modern carbonate systems as subsurface analogues might be enhanced. 相似文献
4.
沉积物粒度分布特征可揭示沉积动力环境。基于广西南流江河口水下三角洲的粒度分析数据,采用Folk分类法进行分类,应用端元分析对其粒度数据进行分解,探讨了南流江河口水下三角洲的物源和现代沉积动力环境。结果表明,研究区表层沉积物可划分为9类,其中含砾沉积物5类,不含砾沉积物4类,沉积物类型与河口环境动力特征相吻合。端元分析结果显示,研究区有5个不同类型的端元,分别代表着5种类型的沉积物动力环境:端元1反映了风浪和潮流对表层沉积物的动力作用;端元2指示了外海涌浪对表层沉积物的作用过程;端元3代表了南流江冲淡水引起的表层沉积物的输运;端元4代表了大陆架残留沉积物;端元5为干扰端元,可能是由于工程建设等人类活动所引起的。利用端元分析探讨复杂环境(如小型山溪性河口)下的沉积动力环境时,一方面需要综合考虑研究区域的物源与环境动力特征;另一方面可以结合参数拟合、粒径趋势分析等研究手段。 相似文献
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6.
Quantification of geodiversity and its loss 总被引：1，自引：0，他引：1
Dmitry A. Ruban 《Proceedings of the Geologists' Association. Geologists' Association》2010,121(3):326-333
Geodiversity, i.e., a diversity of geological heritage sites, can be quantified with an account of geosite types, type counterparts, and their ranks. Higher numbers of geosite types represented within a given territory and their higher ranks indicate a higher geodiversity. Two additional characteristics, namely geoabundance and georichness, allow measure of the quantity of geosites and the diversity-quantity relationship respectively. Geodiversity loss can be evaluated with an accounting of decreases in geosite type ranks linked to the damage of geosites. A calculation of relative and multi-dimensional geodiversity helps in quantitative assessment of the regional geological heritage. 相似文献
7.
GIS-based 2D prospectivity modelling of three greenfield geological regions of Western Australia, namely, the West Arunta Orogen, West Musgrave Orogen and Gascoyne Province, was implemented for a range of deposit types including orogenic and intrusion-related gold, volcanic sediment-hosted base-metal sulfides, magmatic nickel–copper and magmatic platinum group element sulfides, iron-oxide copper gold, tin–tungsten, igneous and metamorphic related rare earth elements, surficial uranium and unconformity-related uranium.Conceptual mineral systems models were generated to identify the targeting criteria. The inputs to the models were the spatial proxies derived from 1:100,000 to 1:500,000 scale public domain data. The results showed similar prospectivity patterns for all of the targeted deposit types except sediment-hosted uranium and surficial uranium deposit types. Once a favourable geodynamic architecture is established, it can sustain different mineral systems and produce diverse deposit types depending on the nature of ligands in the source regions and physical–chemical environment in the trap regions through repeated reactivation in the subsequent geological history. A model is proposed to explain the formation of different deposit types at different stages of tectonic evolution of a province. The implication for GIS-based 2D prospectivity modelling at the scale of geological region is that the prospectivity model may not be deposit type specific. Further, prospectivity modelling should be carried out sequentially at progressively finer scales (regional- to district- to camp-scale), using only the targeting criteria that are relevant at the specific scale to delineate targets for specific deposit types. 相似文献
8.
主要由副长石、长石組成的(碱性) 火成岩的四面体空間投影分类图解含副长石及长石和仅含副长石的火成岩称为碱性岩。碱性岩的产出虽少,其分布面积不超过全部火成岩的1％;但由于矿物组分复杂,岩性变化较大,特定的岩石名称竟占全部岩石名词的35％左右。因此,碱性岩的分类及命名问题,从来就是一个麻烦的事情。 相似文献
9.
A. Cendrero J. S nchez C. Antolin S. Arnal J.R. Diaz de Ter n E. Franc s V. Martí nez M. MoiunÜ o M. Nieto I. Nogales E. P rez C. Rios F. Robles A. Romero C. Sua rez 《Engineering Geology》1990,29(4):291-319
Two case studies of the application of geoscientific maps for planning in semi-arid regions are presented, one for the Mediterranean province of Valencia and another for the island of Gran Canaria (Canaries). Both regions are very dynamic from the point of view of population growth and urban-touristic-industrial development, and they suffer from a serious degree of environmental degradation. The provincial/ island governments have undertaken programmes of geoscientific mapping and assessment to serve as a basis for the establishment of guidelines for future planning.
Two map sets have been made (1:200,000 in Valencia and 1:50,000 in Gran Canaria), based on initial maps of homogeneous integrated units. These represent a series of hierarchical land subdivisions, progressively smaller and more detailed (morphodynamic environments, systems, units, elements), defined on the basis of morphostructure, climate, lithology, surficial deposits, landforms, topography, active processes, soils, vegetation and human influence.
Each individual map unit is described by means of a form which includes 114 items, summarising its environmental features.
Morphodynamic units have been evaluated in terms of qualities significant for planning, and a series of derivative maps has been developed (geologic hazards, soil capability, present degree of erosion, potential erodibility, quality for conservation).
A final map shows the most advisable types of uses and the main limitations for human activities, mainly due to engineering geological factors. This is a synthesis document which can be used directly by planners. 相似文献
10.
Dmitry A. Ruban 《Proceedings of the Geologists' Association. Geologists' Association》2011,122(3):347-352
This is a response to the Correspondence by Knight (Proceedings of the Geologists’ Association, 2011) entitled ‘Evaluating geological heritage’. In this response I suggest that geodiversity can be evaluated (1) conceptually as a natural treasure within landscape, cultural, and historical contexts and (2) numerically as a number of geosite types (not as a number of geosites). These points of view are not conflicting, but mutually profitable. Moreover, broad context and perception of geodiversity can be involved in its quantification. Geodiversity is viewed as a dynamic idea, which modifications will be reflected in every study of the regional geological heritage. 相似文献
11.
《Comptes Rendus Geoscience》2018,350(6):255-266
The Oued Togba and Sebkha Gezmayet units of the Adrar Souttouf Massif in the southern Moroccan Sahara are thought to represent tectonic fragments that may have an affinity to the Avalonian and Meguma terranes of eastern North America. Here we study siliciclastic rocks of the Sebkha Gezmayet unit with respect to their detrital zircon spectra. Beside the commonly used U–Th–Pb ages, several aspects of zircon morphology (length, width, roundness, surficial indicators of sedimentary transport, morphotype) are described. The detrital zircon age spectrum of the Sebkha Gezmayet unit resembles that of the already dated underlying igneous rocks. Occurrences of Early Devonian zircon ages are at odds with the magmatic history of the West African Craton but are common in the Avalonian and Meguma terranes, which were affected by the Appalachian orogenies. The scarcity of Mesoproterozoic detrital zircon grains corroborates the previously suggested Meguma terrane affinity of this part of the Adrar Souttouf Massif. Combining zircon morphology and isotopic data, we propose first assumptions on the sedimentary environments of the Sebkha Gezmayet unit during different periods of the Palaeozoic. 相似文献
12.
Lake sediment and water geochemical data from a complex area of the Canadian shield in Labrador, Canada, display spatial variation patterns that can be linked to bedrock geology. Composite variables derived by R-mode factor analysis are effective in discriminating large-scale lithotectonic divisions, but single-element raw or residual data (corrected for effects of lake depth, Fe, Mn and LOI) provide better resolution of smaller-scale features and major tectonic boundaries.Archean high-grade gneiss regions are typified by high pH and Ni, coupled with depletion of U and F. This signature is developed most strongly over mafic igneous rocks, but is present also over Archean granitoid orthogneisses. Archean crust affected by Proterozoic structural and thermal reworking retains a high Ni signature, but is not depleted in U and F. An Early Proterozoic belt of felsic intrusive and extrusive rocks is defined by enrichment in F, U, Mo, Pb and Zn. Single-element variations suggest large-scale zonation of the belt, with the strongest enrichment over blocks interpreted to represent high crustal levels. Prominent geochemical boundaries coincide with major faults within this belt. High-grade metamorphic terranes comprising Early to Middle Proterozoic crust affected by the 1.0-Ga Grenville Orogeny show low geochemical relief, and are characterized by strong depletion in incompatible elements.In addition to reflecting the dominant rock types in each domain, some of these patterns may be related to the age, erosion level and orogenic history of the crust. For example, the Archean signature may reflect fundamental contrasts in the compositions of Archean and Proterozoic crust, suggested also by lithogeochemical and petrogenetic studies. Geochemical zonation over Early Proterozoic igneous rocks may be a function of crustal level, with the most differentiated granites, volcanic rocks and hydrothermal mineralization present in the uppermost levels of the belt. Depletion of incompatible elements over both Archean and Proterozoic high-grade metamorphic rocks may reflect expulsion of these elements by dehydration and anatexis. 相似文献
13.
Mathematical Geosciences - Three-dimensional geological structure analysis is fundamental to geoscientific research. With the application of artificial intelligence in geological structure... 相似文献
14.
Neoproterozoic Mafic Dykes and Basalts in the Southern Margin of Tarim, Northwest China: Age, Geochemistry and Geodynamic Implications 总被引：4，自引：0，他引：4
<正>Neoproterozoic rifting-related mafic igneous rocks are widely distributed both in the northern and southern margins of the Tarim Block,NW China.Here we report the geochronology and systematic whole-rock geochemistry of the Neoproterozoic mafic dykes and basalts along the southern margin of Tarim.Our zircon U-Pb age,in combination with stratigraphic constraint on their emplacement ages,indicates that the mafic dykes were crystallized at ca.802 Ma,and the basalt, possibly coeval with the ca.740 Ma volcanic rocks in Quruqtagh in the northern margin of Tarim. Elemental and Nd isotope geochemistry of the mafic dykes and basalts suggest that their primitive magma was derived from asthenospheric mantle(OIB-like) and lithospheric mantle respectively,with variable assimilation of crustal materials.Integrating the data supplied in the present study and that reported previously in the northern margin of Tarim,we recognize two types of mantle sources of the Neoproterozoic mafic igneous rocks in Tarim,namely the matasomatized subcontinental lithospheric mantle(SCLM) in the northern margin and the long-term enriched lithospheric mantle and asthenospheric mantle in the southern margin.A comprehensive synthesis of the Neoproterozoic igneous rocks throughout the Tarim Block led to the recognition of two major episodes of Neoproterozoic igneous activities at ca.820-800 Ma and ca.780-740 Ma,respectively.These two episodes of igneous activities were concurrent with those in many other Rodinian continents and were most likely related to mantle plume activities during the break-up of the Rodinia. 相似文献
15.
花岗岩目前的ISMA分类不是一个系统的分类,花岗岩分类可能需要从花岗岩的起源来考虑。花岗岩源自变质岩,可能是来自地幔或玄武质岩浆底侵带来的热导致的下地壳底部发生部分熔融的熔体形成的。因此,花岗岩与变质岩源岩有成因联系和因果关系,变质岩为母,花岗岩为子。根据埃达克岩与残留相平衡的理论,埃达克岩形成于斜长石消失线之上。那么,出现在石榴石出现线之上的是什么花岗岩呢?出现在石榴石出现线之下的又是什么花岗岩呢?本文即尝试从这个思路来探讨花岗岩的分类,并采用大数据方法予以佐证,得到的初步结果可以将花岗岩分为3类:(1)位于斜长石消失线之上的为高Sr低Y型花岗岩(高压,代表加厚的地壳);(2)位于斜长石消失线与石榴石出现线之间的为低Sr低Y类型花岗岩(中压,代表正常厚度的地壳);(3)位于石榴石出现线之下的为高Y型花岗岩(低压,代表减薄的地壳)。大数据研究的结果支持上述分类,给出的地球化学标志大体是:Sr含量为400×10-6,Y含量为(20~35)×10-6。 相似文献
16.
T. A. Semeniuk 《Australian Journal of Earth Sciences》2019,66(6):793-802
The geology of New South Wales is diverse, spanning Paleoproterozoic to modern materials and their various associated landforms and soils. In recognition of the intrinsic geological value of the State, around 150 geological sites were nominated to the now defunct Register of the National Estate, with the objective of geoconservation. However, these sites did not encompass the full range of geology of New South Wales; neither did they offer registered sites any protection. Analysis shows that the types of sites nominated were biased towards sedimentary and igneous rocks, and fossils, with under representation of metamorphic rocks, site-restricted soils, geomorphology and hydrogeology. To test the utility of the Brocx and Semeniuk ‘Geoheritage Toolkit’, a subset of the Register listings was re-examined, focusing on the Sydney Basin. Within the Sydney Basin, 59 nominated sites were reassessed using various geoheritage categories and the hierarchical framework of scale of the Toolkit. Four sites within the Sydney Basin were found to have features of international to national significance, and to have national historical value. These sites will need to be renominated for State and National listing. Clearly, to ensure that University teaching sites, as well as stratigraphic and lithologic type sections and reference sites, reflecting the geodiversity of New South Wales are conserved for future generations, a greater number of sites need to be put forward for heritage listing. 相似文献
17.
文章利用海南岛SOTER数据库及自动土地评价模型ALES评价结果,对海南岛4种主要母岩上发育的土壤类型、土壤性质及香蕉种植适宜性与母质的关系进行了分析。海南岛不同母岩上土壤类型的发育呈现多样性,土壤类型的分布明显受到母岩类型、成土年龄、成土环境等因素的影响。酸性火成岩上主要发育有雏形土和富铁土,基性岩上则主要是发育良好的铁铝土,碎屑岩上主要是雏形土,而海相沉积物由于土壤形成时间的差异出现了多样的土壤类型。在海南岛湿热的气候条件下,原生母岩上发育的土壤,尽管成土母岩成分各不相同,但一些土壤性质已经没有明显差别,如交换性钙、镁、钠等,部分土壤化学性质如交换性钾的含量继承了母岩特性。各种母岩上发育的土壤,在自然条件下,适宜香蕉种植的比例都很低,但基性火成岩和海积物上发育的土壤,更容易受到人为管理措施的影响,如果满足一定的技术和经济投入,海南岛热带作物的种植潜力可以得到进一步的挖掘。 相似文献
18.
尝试用稀土分布的分形结构因子（FSF）值对我国碱性花岗岩的稀土组成进行了分类。可将我国碱性花岗岩的稀土分布分形结构因子划分为4种类型：（1）弱变异型（0．98－0．95）；（2）中变异型（0．95－0．92）；（3）强变异型（0．92－0．89）；（4）超强变异型（0．89－0．86）。其中前两种类型可很好地对应重稀土富集型和中稀土亏损型花岗岩，而后两种类型可对应轻稀土相对富集型和轻稀土特富型花岗岩。利用FSF值对新疆东准噶尔地区三带富碱花岗岩按稀土组成进行了归类。 相似文献
19.
准噶尔盆地石炭系中发现自生自储的大型火山岩油气藏,这不仅大大拓宽了油气勘探领域,而且从含油气盆地原型恢复角度为我们提出了一个新的命题。本文对准噶尔盆地东部的石炭纪盆地进行了剖析,在井间地层对比和锆石U-Pb同位素年代学测定基础上,确定了准噶尔盆地石炭系划分方案,建立了准东地区及邻区石炭系的5条联井对比骨干地质剖面,进而把准东地区石炭系盆地的充填过程划分为两个旋回、7个阶段,其中第一旋回为早石炭世,进一步分为4个阶段,第1至第3阶段以各种火山岩发育为特征,第4阶段为火山活动的间歇期,发育了暗色泥质岩。第二旋回为晚石炭世,进一步分为3个阶段,第5和第6两个阶段以发育中基性火山岩为特征,第7阶段以沉火山凝灰岩和与泥质岩、砂岩互层发育为特征。文中归纳了准东地区石炭纪盆地及其中火山岩油气藏烃源岩和储层的发育特点,建立了其盆地原型,指出准东地区石炭系在沉积时的构造古地理以多岛洋为特征,受准噶尔洋的持续向北东方向俯冲的影响,准东地区盆地基底向南西方向倾斜,造成了沉积中心的向南西迁移。考虑到盆地位于增生型造山带内,将其原型盆地称为增生楔盆地。文中特别指出,任何构造位置上形成的盆地都有形成大油气田的潜力,能否形成大油气田的关键在于有没有优质烃源岩、优质储层和有效圈闭。准东增生楔盆地中烃源岩与火山岩储层的空间关系十分密切,二者往往形成互层状或穿插状,这一特征决定了盆地中油气产出具有近源性,而圈闭的形成则因火山岩储层的成层性差而呈形态和类型的多样性。 相似文献