Signatures of Divergence and Self-Organization in Soils and Weathering Profiles

Complex system behaviors such as self-organization are difficult to address in geology. System evolution often cannot be directly observed and, in geology models and theory, must be reconciled with field evidence. However, self-organization can be addressed within the historical-interpretive paradigm by applying a measure of the degree of self-organization of geologic features, using standard interpretive methods to determine the nature of changes, and determining whether those changes result in an increase or decrease in organization. In this way, stable non-self-organizing convergent development can be distinguished from unstable chaotic self-organizing divergent development. Kolmogorov entropy (K-entropy) was used as a measure of the self-organization of soil profiles in eastern North Carolina. In general, the profiles are low in K-entropy, indicating a generally high level of predictability and information in the vertical arrangement of pedogenetic horizons. As a broad generality, the study profiles appear to be decreasing in entropy if or when surface erosion is minimal and increasing in entropy otherwise. However, results show that whether the profiles demonstrate evidence of convergent or divergent behavior is determined by the relative rates or magnitudes of three main processes: (1) horizon differentiation in surficial horizons by the formation of transitional AE or A&E horizons due to secondary podzolization, (2) thickening of the solum at the weathering front, and (3) surface erosion. There is no direct relationship between the degree of pedogenic development and self-organization. The results suggest that complex system behaviors are controlled by, and can be linked to, specific pedologic and geomorphic processes and that soils and regoliths may be characterized by both convergent and divergent developmental pathways.     

Curved branching crystals and differentiation in comb-layered rocks

Layering in which one or more of the component minerals has grown perpendicular to layer boundaries occurs, under a variety of names, in volcanic, hypabyssal nad plutonic igneous rocks. The most recent and best name is comb layering. The oriented minerals are elongate, are commonly branching and may be curved. Experimental crystallization of plagioclase and ternary feldspar melts confirms that a substantial degree of supercooling 01 a significant cooling rate is necessary to produce the curved or branching crystal morphologies typical of comb layering. The more viscous the melt, the less the supercooling required. Changes in the water content or confining pressure are mechanisms for inducing supersaturation in deep-seated magmas, that are consistent with field and experimental evidence. The change from modal dominance by a single elongate crystal phase in one comb layer to dominance by another phase in a contiguous comb layer is explained by the presence of constitutional supercooling ahead of the growing crystals of a given layer.     

A time-space model for the distribution of shoreline archaeological sites in the lake superior basin

Archaeological site interpretation can be enhanced by consideration of related geological and geomorphological processes. Lake Superior has a history of glaciation, isostatic recovery, and water-level change. Two examples are given of shoreline sites at which interpretation is enhanced by an understanding of local geologic factors. The archaeologic history of the Lake Superior basin is reviewed, and three cultural traditions are recognized; (1) Paleoindian, (2) Archaic, and (3) Woodland. Three significant factors of geologic history are then discussed: (1) ice margin oscillation, (2) differential isostatic uplift, and (3) lake-level fluctuations. The factors reducing or improving shoreline archaeological site preservation are examined, and a summary model of shoreline site distribution for the Lake Superior basin is offered. It is concluded that the north shore provides the best potential for a complete archaeological record. © 1993 John Wiley & Sons, Inc.     

Manual hierarchical clustering of regional geochemical data using a Bayesian finite mixture model

Interpretation of regional scale, multivariate geochemical data is aided by a statistical technique called “clustering.” We investigate a particular clustering procedure by applying it to geochemical data collected in the State of Colorado, United States of America. The clustering procedure partitions the field samples for the entire survey area into two clusters. The field samples in each cluster are partitioned again to create two subclusters, and so on. This manual procedure generates a hierarchy of clusters, and the different levels of the hierarchy show geochemical and geological processes occurring at different spatial scales. Although there are many different clustering methods, we use Bayesian finite mixture modeling with two probability distributions, which yields two clusters. The model parameters are estimated with Hamiltonian Monte Carlo sampling of the posterior probability density function, which usually has multiple modes. Each mode has its own set of model parameters; each set is checked to ensure that it is consistent both with the data and with independent geologic knowledge. The set of model parameters that is most consistent with the independent geologic knowledge is selected for detailed interpretation and partitioning of the field samples.     

地面核磁共振-垂向电测深组合找水模式

地面核磁共振方法具有直接找水、提供水文地质参数、受地形影响小、垂向分辨率高、经济快速等优点,但它同时也具有易受电磁噪声干扰、横向分辨精度低、勘探深度小等缺点.垂向电测深方法具有技术成熟、不易受电磁噪声干扰、勘探深度大、横向分辨率高等优点,但它同时也具有反演解释存在多解性、定量解释不足、垂向分辨率低等缺点.通过比较地面核磁共振方法与垂向电测深方法的优缺点得知,2种找水方法具有优势互补的特点,合理配合使用上述2种找水方法,可形成地面核磁共振-垂向电测深组合找水模式.该组合找水模式在找水实践工作中的有效性已得到充分验证.     

On the Layering Artifacts in Seismic Imageries

A common feature in seismic imageries of the crust and mantle is a layering pattern.Layering structures do exist in multiple scales,such as layered strata and unconformities in local and regional scales,and undulating seismic discontinuities in the crust and mantle.However,layering arti-fact also exists due to limitations in seismic processing and data coverage.There is a tendency for seis-mic stacking methods to over-map reflectors and scatters into along-isochron layers.In contrast,seis-mic tomography met...     

Influence of geologic layering on heat transport and storage in an aquifer thermal energy storage system

A modeling study was carried out to evaluate the influence of aquifer heterogeneity, as represented by geologic layering, on heat transport and storage in an aquifer thermal energy storage (ATES) system in Agassiz, British Columbia, Canada. Two 3D heat transport models were developed and calibrated using the flow and heat transport code FEFLOW including: a “non-layered” model domain with homogeneous hydraulic and thermal properties; and, a “layered” model domain with variable hydraulic and thermal properties assigned to discrete geological units to represent aquifer heterogeneity. The base model (non-layered) shows limited sensitivity for the ranges of all thermal and hydraulic properties expected at the site; the model is most sensitive to vertical anisotropy and hydraulic gradient. Simulated and observed temperatures within the wells reflect a combination of screen placement and layering, with inconsistencies largely explained by the lateral continuity of high permeability layers represented in the model. Simulation of heat injection, storage and recovery show preferential transport along high permeability layers, resulting in longitudinal plume distortion, and overall higher short-term storage efficiencies.     

Review of interactions between phosphorus and arsenic in soils from four case studies

Arsenic is a non-essential element that poses risks in many environments, including soil, groundwater, and surface water. Insights into the environmental biogeochemistry of As can be gained by comparing As and P reaction processes. Arsenic and P are chemical analogues, and it is proposed that they have similar chemical behaviors in environmental systems. However some chemical properties of As and P are distinct, such as redox reactions, causing the biogeochemical behavior of the two elements to differ. In the environment, As occurs as either As(V) or As(III) oxyanions (e.g., AsO₄^3? or AsO₃^3?). In contrast, P occurs predominantly as oxidation state five plus; most commonly as the orthophosphate ion (PO₄^3?). In this paper, data from four published case studies are presented with a focus on P and As distribution and speciation in soil. The goal is show how analyzing P chemistry in soils can provide greater insights into As reaction processes in soils. The case studies discussed include: (1) soil developed from shale parent material, (2) mine-waste impacted wetland soils, (3) phosphate-amended contaminated soil, and (4) plants grown in biochar-amended, mine-contaminated soil. Data show that while P and As have competitive reactions in soils, in most natural systems they have distinct biogeochemical processes that create differing mobility and bioavailability. These processes include redox reactions and rhizosphere processes that affect As bioavailability. Results from these case studies are used as examples to illustrate how studying P and As together allows for enhanced interpretation of As biogeochemical processes in soils.     

Vertical harmonic vibration of piled raft foundations in layered soils

This paper develops a method to analyze the piled raft foundation under vertical harmonic load. This method takes into account the interactions among the piles, soil, and raft. The responses of the piles and raft are formulated as a series of equations in a suitable way and that of layered soils is simulated with the use of the analytical layer‐element method. Then, according to the equilibrium and continuity conditions at the piles–soil–raft interface, solutions for the piled raft systems are obtained and further demonstrated to be correct through comparing with the existing results. Finally, some examples are given to investigate the influence of the raft, pile length‐diameter ratio, and layering on the response of the piled raft foundations. Copyright © 2017 John Wiley & Sons, Ltd.     

Characterization of the Cretaceous aquifer structure of the Meskala region of the Essaouira Basin,Morocco

The aquifer of early Cretaceous age in the Meskala region of the Essaouira Basin is defined by interpretation of geological drilling data of oil and hydrogeological wells, field measurement and analysis of in situ fracture orientations, and the application of a morphostructural method to identify lineaments. These analyzes are used to develop a stratigraphic–structural model of the aquifer delimited by fault zones of two principal orientations: NNE and WNW. These fault zones define fault blocks that range in area from 4 to 150 km². These blocks correspond either to elevated zones (horsts) or depressed zones (grabens). This structural setting with faults blocks of Meskala region is in accordance with the structure of the whole Essaouira Basin. Fault zones disrupt the continuity of the aquifer throughout the study area, create recharge and discharge zones, and create dip to the units from approximately 10° to near vertical in various orientations. Fracture measurements and morphometric-lineament analyzes help to identify unmapped faults, and represent features important to groundwater hydraulics and water quality within fault blocks. The above geologic features will enable a better understanding of the behaviour and hydro-geo-chemical and hydrodynamics of groundwater in the Meskala aquifer.     

某水电站引水硐进水口边坡稳定性分析

介绍了某水电站引水硐进水口边坡的基本地质条件，从地形地貌特征、岩土工程地质特征、岸坡地质结构特征和地质构造条件几个因素系统的研究其对边坡变形破坏的影响，提出了边坡的变形破坏模式。根据平洞揭露裂隙特征，对可能的滑面组合采用毕肖普、一般条分法和摩根斯坦普顿斯法等方法对进水口边坡进行稳定性分析和计算，最后对边坡的安全性进行了评价。     

Consolidation around a heat source buried deep in a porous thermoelastic medium with anisotropic flow properties

A solution is derived for the heat flow and consolidation which occur when a heat source is buried deep in a porous thermoelastic soil having anisotropic flow properties. This solution is used to examine the pore pressure generation and dissipation near both point and cylindrical heat sources. An increase in temperature will tend to generate an increase in excess pore pressure. However, the pore water will tend to flow from regions of high excess pore pressure to regions of low excess pore pressure, and so consolidation will occur, and temperature-generated excess pore pressures will tend to dissipate. Many natural soils exhibit horizontal layering and so have a higher horizontal than vertical permeability. It is shown that in soils the excess pore pressure generated by a heat source is significantly less than that in an isotropic soil having an equal vertical permeability.     

Detection of free vertical convection and double-diffusion in groundwater monitoring wells with geophysical borehole measurements

Two algorithms for in-situ detection and identification of vertical free convective and double-diffusive flows in groundwater monitoring wells or boreholes are proposed. With one algorithm the causes (driving forces) and with the other one the effects (convection or double-diffusion) of vertical transport processes can be detected based on geophysical borehole measurements in the water column. Five density-driven flow processes are identified: thermal, solutal, and thermosolutal convection leading to an equalization, as well as saltfingers and diffusive layering leading to an intensification of a vertical density gradient. The occurrence of density-driven transport processes could be proven in many groundwater monitoring wells and boreholes; especially shallow sections of boreholes or groundwater monitoring wells are affected dramatically by such vertical flows. Deep sections are also impaired as the critical threshold for the onset of a density-driven flow is considerably low. In monitoring wells or boreholes, several sections with different types of density-driven vertical flows may exist at the same time. Results from experimental investigations in a medium-scale testing facility with high aspect ratio (height/radius = 19) and from numerical modeling of a water column agree well with paramters of in-situ detected convection cells.     

Interpretation of cone penetration results in multilayered soils

A simple approximate analysis is presented for interpretation of cone penetration results when the cone resistance is affected by layering of soils with different stiffnesses. It is argued that the cone resistance senses the presence of a nearby layer elastically, and an approximate elastic analysis is developed to quantify the effect. Good comparisons with calibration chamber experimental results are found.     

Advanced techniques in site characterization and mining hazard detection for the underground coal industry

Today's highly productive coal mining systems represent large capital investments. Careful geotechnical planning and design are essential to protect these systems and to help ensure their overall success. Too often, however, the ability of the mine operator to adequately characterize the geotechnical environment and keep up with changing geologic conditions lags the advance rate of the mining equipment. Seismic tomographic imaging, based on the same principles as medical Computer-Aided-Tomography (CAT) Scans, offers the ability to identify changing geologic conditions, loading patterns, and the location of nearby abandoned mine workings. Although seismic tomography has been used for many years in the oil industry, until recently its practicality in the mining industry has been limited because the processes involved interfered with mining productivity and were labor-intensive in terms of data collection and interpretation. New advancements in signal processing have greatly enhanced the speed, resolution, and range of applications of tomographic imaging in underground coal mine settings.Many tomography applications in the mining industry use seismic velocity and/or attenuation tomography within a volume enclosed by the seismic source and receiver array. Although results obtained using this geometry work well in many situations, recent developments in reflection tomography show promise in eliminating the requirement that the target volume be surrounded by sources/receivers. For example, in-seam seismic reflection tomography may now be used to image structures and/or old workings from one general location in the mine (e.g., face areas of mains and panel developments) well ahead of planned developments—largely eliminating the need to probe-hole drill on regular intervals. These new developments have greatly expanded the ability of the mine operator to cost-effectively characterize previously inaccessible areas of the property.This paper gives an overview of the theories and processes involved in seismic tomography applicable to coal mine settings. Recent examples are presented of tomographic imaging applied to a variety of coal mine ground control problems and old works detection in the United States and Europe. The applicability of both seismic refraction and seismic reflection tomography is discussed.     

瑞利波探测在石炭井三矿的应用

针对石炭井三矿的具体地质、地球物理条件介绍了矿井瑞利波系统在井下的施工、数据采集、资料处理、解释推断等诸方面的方法技术。举例指出该探测系统在剩余煤层厚度探测、掘进巷道超前探测地质构造、石门揭煤判断煤层位置几个方面的地质效果。      

Mineral growth in melt conduits as a mechanism for igneous layering in shallow arc plutons: mineral chemistry of Fisher Lake orbicules and comb layers (Sierra Nevada,USA)

Different processes have been proposed to explain the variety of igneous layering in plutonic rocks. To constrain the mechanisms of emplacement and crystallization of ascending magma batches in shallow plutons, we have studied comb layers and orbicules from the Fisher Lake Pluton, Northern Sierra Nevada. Through a detailed study of the mineralogy and bulk chemistry of 70 individual layers, we show that comb layers and orbicule rims show no evidence of forming through a self-organizing, oscillatory crystallization process, but represent crystallization fronts resulting from in situ crystallization and extraction of evolved melt fractions during decompression-driven crystallization, forming a plagioclase-dominated cres-cumulate at the mm- to m-scale. We propose that the crystal content of the melt and the dynamics of the magmatic system control the mechanisms responsible for vertical igneous layering in shallow reservoirs. As comb layers crystallize on wall rocks, the higher thermal gradients will increase the diversity of comb layering, expressed by inefficient melt extraction, thereby forming amphibole comb layers and trapped apatite + quartz saturated evolved melt fractions. High-An plagioclase (An₉₀–An_97.5) is a widespread phase in Fisher lake comb layers and orbicule rims. We show that a combination of cooling rate, latent heat of crystallization and pressure variations may account for high-An plagioclase in shallow melt extraction zones.     

The petrology of a melilitolite,melteigite, carbonatite and syenite ring dike system,in the Gardiner complex,East Greenland

The Tertiary Gardiner complex in East Greenland comprises ultramafic cumulates cut by dikes, ring dikes and cone sheets. One major ring dike is of melilite-rick rocks (melilitolites), and shows phase layering and cryptic layering with respect to melilite, perovskite and phologopite. The vertical variation in the assemblages through the ring dike is consistent with established fractionation trends in undersaturated melilite-bearing experimental systems. Related veins and dikes are: a) undersaturated rocks of the melteigite-ijolite-urtite/nepheline syenite suite, b) melanite-calcite veins and søvite dikes and sheets and c) coarse-grained magnetite-phlogopite-diopside-calcite pegmatites and dolomite rocks. It is proposed that a CO₂-bearing Ln-normative nephelinite liquid is parential to both melilitolites and related veins through a combination of fractional crystallization, liquid immiscibility and CO₂-metasomatism of dunite country rocks. Unlike other localities where melilitolites are attributed to metasomatic processes, the Gardiner melilitolites are magmatic.     

Prior model identification during subsurface flow data integration with adaptive sparse representation techniques

Construction of predictive reservoir models invariably involves interpretation and interpolation between limited available data and adoption of imperfect modeling assumptions that introduce significant subjectivity and uncertainty into the modeling process. In particular, uncertainty in the geologic continuity model can significantly degrade the quality of fluid displacement patterns and predictive modeling outcomes. Here, we address a standing challenge in flow model calibration under uncertainty in geologic continuity by developing an adaptive sparse representation formulation for prior model identification (PMI) during model calibration. We develop a flow-data-driven sparsity-promoting inversion to discriminate against distinct prior geologic continuity models (e.g., variograms). Realizations of reservoir properties from each geologic continuity model are used to generate sparse geologic dictionaries that compactly represent models from each respective prior. For inversion initially the same number of elements from each prior dictionary is used to construct a diverse geologic dictionary that reflects a wide range of variability and uncertainty in the prior continuity. The inversion is formulated as a sparse reconstruction problem that inverts the flow data to identify and linearly combine the relevant elements from the large and diverse set of geologic dictionary elements to reconstruct the solution. We develop an adaptive sparse reconstruction algorithm in which, at every iteration, the contribution of each dictionary to the solution is monitored to replace irrelevant (insignificant) elements with more geologically relevant (significant) elements to improve the solution quality. Several numerical examples are used to illustrate the effectiveness of the proposed approach for identification of geologic continuity in practical model calibration problems where the uncertainty in the prior geologic continuity model can lead to biased inversion results and prediction.