HFSE‐REE Transfer Mechanisms During Metasomatism of a Late Miocene Peraluminous Granite Intruding a Carbonate Host (Campiglia Marittima, Tuscany)

The different generations of calc‐silicate assemblages formed during sequential metasomatic events make the Campiglia Marittima magmatic–hydrothermal system a prominent case study to investigate the mobility of rare earth element (REE) and other trace elements. These mineralogical assemblages also provide information about the nature and source of metasomatizing fluids. Petrographic and geochemical investigations of granite, endoskarn, and exoskarn bodies provide evidence for the contribution of metasomatizing fluids from an external source. The granitic pluton underwent intense metasomatism during post‐magmatic fluid–rock interaction processes. The system was initially affected by a metasomatic event characterized by circulation of K‐rich and Ca(‐Mg)‐rich fluids. A potassic metasomatic event led to the complete replacement of magmatic biotite, plagioclase, and ilmenite, promoting major element mobilization and crystallization of K‐feldspar, phlogopite, chlorite, titanite, and rutile. The process resulted in significant gain of K, Rb, Ba, and Sr, accompanied by loss of Fe and Na, with metals such as Cu, Zn, Sn, W, and Tl showing significant mobility. Concurrently, the increasing fluid acidity, due to interaction with Ca‐rich fluids, resulted in a diffuse Ca‐metasomatism. During this stage, a wide variety of calc‐silicates formed (diopside, titanite, vesuvianite, garnet, and allanite), throughout the granite body, along granite joints, and at the carbonate–granite contact. In the following stage, Ca‐F‐rich fluids triggered the acidic metasomatism of accessory minerals and the mobilization of high-field-strength elements (HFSE) and REE. This stage is characterized by the exchange of major elements (Ti, Ca, Fe, Al) with HFSE and REE in the forming metasomatic minerals (i.e., titanite, vesuvianite) and the crystallization of HFSE‐REE minerals. Moreover, the observed textural disequilibrium of newly formed minerals (pseudomorphs, patchy zoning, dissolution/reprecipitation textures) suggests the evolution of metasomatizing fluids towards more acidic conditions at lower temperatures. In summary, the selective mobilization of chemical components was related to a shift in fluid composition, pH, and temperature. This study emphasizes the importance of relating field studies and petrographic observations to detailed mineral compositions, leading to the construction of litho‐geochemical models for element mobilization in crustal magmatic‐hydrothermal settings.

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COMPUTER CODES OF GEOCHEMICAL MODELING USED TO WATER-ROCK INTERACTION SIMPLE AND COMPLEX SYSTEMS

Periódico Tchê Química ◽

10.52571/ptq.v16.n32.2019.137_periodico32_pgs_108_118.pdf ◽

2019 ◽

Vol 16 (32) ◽

pp. 108-118

Author(s):

Marcos Antônio KLUNK ◽

Sudipta DASGUPTA ◽

Mohuli DAS ◽

Paulo Roberto WANDER

Keyword(s):

Complex Systems ◽

Geochemical Modeling ◽

Chemical Properties ◽

Coupled Transport ◽

Burial History ◽

Batch Mode ◽

Data Set ◽

Rock Interaction ◽

Geochemical Reactions ◽

Geochemical Models

The numerical modeling of transport and reaction was used for the understanding of the evolution of the diagenetic processes and their importance in the characterization and prediction of oil reservoir quality. Geochemical models are represented by numerical equations based on the physical-chemical properties of minerals. There are many software’s available in the market to simulate systems and geochemical reactions. The codes are divided into three distinct categories: coupled transport of reaction, modeling speciation, and batch mode according to the numerical method. Simple systems have clear connections between inputs and outputs. Complex systems have multiple factors that provide a probability distribution of data inputs that interact in specific functions. The outputs produced as a result are therefore impossible to predict with complete accuracy. Several research groups tried to develop numerical codes for geochemical modeling. The critical factors for the use of these systems are (i) verification of the simulation results with empirical data set and (ii) sensitivity analysis of these results, for the construction of general models which provide a predictive character. This last factor is particularly important as it establishes the qualitative and quantitative impact of each parameter in the simulations. Thus, with a complete numerical model diagenetic, it is possible to perform various simulations modifying one or the other parameter to test the sensitivity in the construction of these different geological scenarios. This set includes mineral composition and texture, the composition of fluids, paragenetic sequence, and burial history. This work brings fundamental concepts related to this topic as well as an analysis of commercial software available.

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Quality Assessments of Shallow Groundwaters for Drinking and Irrigation Purposes: Insights from a Case Study (Jinta Basin, Heihe Drainage Area, Northwest China)

Water ◽

10.3390/w12102704 ◽

2020 ◽

Vol 12 (10) ◽

pp. 2704 ◽

Cited By ~ 1

Author(s):

Jianguo Feng ◽

Hao Sun ◽

Minghao He ◽

Zongjun Gao ◽

Jiutan Liu ◽

...

Keyword(s):

Drinking Water ◽

Shallow Groundwater ◽

Northwest China ◽

Chemical Components ◽

Agricultural Irrigation ◽

Weakly Alkaline ◽

Rock Interaction ◽

Evaporative Concentration ◽

Major Factors

This study aimed to determine the hydrochemical characteristics and hydrogeochemical processes of shallow groundwater in the Jinta Basin, northwest China, and to evaluate the suitability of groundwater quality for drinking water and agricultural irrigation. A systematic hydrogeological survey was conducted in the study area from May 2017 to October 2018, during which 123 representative samples of groundwater were selected for analysis of chemical parameters and determination of the water quality index. The results showed that the pH of groundwater in the study area was weakly alkaline and ranged between 7.21–8.93. Dominant cations were Mg2+ and Na+ and the dominant anion was SO42−. Along the groundwater flow from the southwest to northeast, the dominant groundwater chemistry type in the recharge area was Mg-HCO3·SO4. After the transition of the groundwater types in the runoff area to Mg-SO4·HCO3 and Mg·Na-SO4, the groundwater type in the discharge area evolved into Na·Mg-SO4·Cl. The major factors driving the evolution of groundwater chemical types in the Jinta Basin were found to be rock weathering, evaporation and precipitation. The chemical components of groundwater mainly originated from the dissolution of silicate rock and evaporative concentration of salt under water-rock interaction, whereas the dissolution of carbonate had little influence. The quality of drinking water was divided into five groups, and 39.84% of samples fell within the high and good quality groups. The quality of agricultural irrigation water was divided into different grades according to different methods.

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Time evolution of groundwater quality in Dehui City

E3S Web of Conferences ◽

10.1051/e3sconf/20199809031 ◽

2019 ◽

Vol 98 ◽

pp. 09031

Author(s):

Hongyang Wei ◽

Xiujuan Liang

Keyword(s):

Groundwater Quality ◽

Chemical Components ◽

Chemical Concentration ◽

Rock Interaction ◽

Songhua River ◽

Development And Utilization ◽

Hydrogeological Analysis ◽

Hydrogeological Data ◽

Water Rock Interaction

The unreasonable development and utilization of groundwater in Dehui City, China, has resulted in poor groundwater quality conditions. Based on the collection of a large amount of groundwater chemical data and hydrogeological data collected by Dehui City from 1992 to 2015, this paper uses hydrogeological analysis, graphic and other methods and ArcGIS toolbox to analyze the groundwater quality of this City. The study shows that the concentration of groundwater chemical components in the vicinity of the Songhua River is decreasing with time, and the concentration of groundwater chemical components in other regions is increasing with time. The increase of chemical concentrations are affected by human activities and water-rock interaction. The decrease of groundwater chemical concentration in Songhua River area is caused by the mixing between dilute river water and groundwater.

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Trace-element mobilization during Ca-metasomatism along a major fluid conduit: Eclogitization of blueschist as a consequence of fluid–rock interaction

Geochimica et Cosmochimica Acta ◽

10.1016/j.gca.2009.12.011 ◽

2010 ◽

Vol 74 (6) ◽

pp. 1892-1922 ◽

Cited By ~ 115

Author(s):

Andreas Beinlich ◽

Reiner Klemd ◽

Timm John ◽

Jun Gao

Keyword(s):

Trace Element ◽

Rock Interaction ◽

Element Mobilization

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Influences of natural and anthropogenic processes on the groundwater quality in the Dagujia River Basin in Yantai, China

Journal of Water Supply Research and Technology—AQUA ◽

10.2166/aqua.2019.113 ◽

2019 ◽

Vol 69 (2) ◽

pp. 184-196 ◽

Cited By ~ 1

Author(s):

Henghua Zhu ◽

Jianwei Zhou ◽

Tingting Song ◽

Haibo Feng ◽

Zhizheng Liu ◽

...

Keyword(s):

Groundwater Quality ◽

Seawater Intrusion ◽

Human Activities ◽

Industrial Development ◽

Anthropogenic Activities ◽

Total Hardness ◽

Chemical Components ◽

Chemical Compositions ◽

Rock Interaction ◽

Natural Processes

Abstract Groundwater plays an important role in water supply and economic development for Yantai city, China. However, the groundwater quality has degraded due to the increase and expansion of agricultural and industrial development. It is urgent to acquire groundwater characteristics and distinguish impacts of natural factors and anthropogenic activities on the groundwater quality. Forty-six groundwater samples collected from different wells showed a great variation of chemical components across the study area. Most wells with higher total dissolved solids, total hardness, K+, Na+, Ca2+, Mg2+, Cl− and SO42− concentrations were located relatively close to the coastal zone. The factor analysis (FA) and hierarchical cluster analysis results displayed that seawater intrusion was the primary mechanism controlling the groundwater quality in the coastal areas. A three-factor model was proposed based on the FA and explained over 85% of the total groundwater quality variation: Factor 1, the seawater intrusion; Factor 2, the water–rock interaction and Factor 3 (NO3−), the human activities. Furthermore, the geographical maps of the factor scores clearly described the spatial distributions of wells affected by natural processes or human activities. The study indicated that both natural processes and human activities are the major factors affecting the chemical compositions of groundwater.

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The Potential Water Quality Impacts of Shale Gas Exploitation

10.5194/egusphere-egu2020-16255 ◽

2020 ◽

Author(s):

Hsiao-Yuan Tammy Hsu ◽

Fred Worrall ◽

Andy Aplin

Keyword(s):

Chemical Composition ◽

Hydraulic Fracturing ◽

Shale Gas ◽

Fluid Composition ◽

Potential Contribution ◽

Sources Of Information ◽

Geothermal Waters ◽

Rock Interaction ◽

The Uk

&#160; &#160;&#160; The potential development of shale gas has brought with it several concerns about environmental impacts, these include: induced seismicity, air pollution, and groundwater contamination. During hydraulic fracturing for shale gas, large volumes of oxic and acidic water are injected into the gas-bearing formations. The injected fluids contain a range of additives and will mix and react with the in-situ groundwater and shale rock with the potential to drive water-rock interactions; release metal contaminants; alter the permeability of the bedrock; with each of these affecting the transport and recovery of water, hydrocarbons, and contamination. The purpose of this study is to understand the geochemical processes and inorganic metals release during hydraulic fracturing to assess the potential contribution of fluid-rock interaction for the composition of produced waters and alteration of shale mechanical properties. &#160; &#160; &#160;The study has:&#160; i) Statistically analysed the chemical composition of hydraulic fracturing in USGS dataset to create prior distributions for the prediction of the salinity and chemical composition of flowback fluids in the UK.&#160; ii) Statistically analysed the composition and controls on geothermal waters in the UK. Deep geothermal waters are an analogue for the in-situ groundwater composition with which injected fracking fluids will react and mix. iii) Both sources of information have assisted in the design of the high pressure, high temperature experiments that will simulate the fracking fluid processes iv) Undertaken sequential extraction of target shales to understand the data from existing batch experiments undertaker&#160; &#160;&#160; Future work will include isotope proxy and mineralogical texture studies to predict flowback fluid composition and the post-frack condition of the shale.

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Dolomitization of Paleozoic Successions, Huron Domain of Southern Ontario, Canada: Fluid Flow and Dolomite Evolution

Water ◽

10.3390/w13172449 ◽

2021 ◽

Vol 13 (17) ◽

pp. 2449

Author(s):

Ihsan S. Al-Aasm ◽

Richard Crowe ◽

Marco Tortola

Keyword(s):

Regional Scale ◽

Carbon Isotopic Composition ◽

Warm Water ◽

Geochemical Data ◽

Fluid Composition ◽

Rock Interaction ◽

Near Surface ◽

Southern Ontario ◽

Ce Anomaly ◽

Diagenetic Fluids

Integrated petrographic, isotopic, fluid inclusion microthermometry, and geochemical analyses of Paleozoic carbonate successions from multiple boreholes within the Huron Domain, southern Ontario were conducted to characterize the diagenetic history and fluid composition, on a regional scale, and evaluate the nature and origin of dolomitized beds. Multiple generations of non-stochiometric dolomite have been observed. These dolomites occur as both replacement (D1 and D2) and cement (saddle dolomite; SD) and formed either at near-surface to shallow burial zone (D1) or intermediate burial (D2 and SD). Petrographic and geochemical data of dolomite types and calcite cement suggest that these carbonates have experienced multiple fluid events that affected dolomite formation and other diagenetic processes. Cambrian and Ordovician strata have two possibly isolated diagenetic fluid systems; an earlier fluid system that is characterized by a pronounced negative shift in oxygen and carbon isotopic composition, more radiogenic Sr ratios, warm and saline signatures, higher average ∑REE compared to warm water marine brachiopods, negative La anomaly, and positive Ce anomaly; and a later Ordovician system, characterized by less negative shifts in oxygen and carbon isotopes, comparable Th, hypersaline, a less radiogenic, less negative La anomaly, and primarily positive Ce anomaly but also higher average ∑REE compared to warm water marine brachiopods. Ordovician, Silurian, and Devonian Sr isotopic ratios, however, show seawater composition of their respective age as the primary source of diagenetic fluids with minor rock/water interactions. In contrast, the isotopic data of the overlying Silurian and Devonian carbonates show overlaps between δ13C and δ18O values. However, δ18O values show evidence of dolomite recrystallization. D2 shows wide Th values and medium to high salinity values. Higher Th and salinity are observed in SD in the Silurian carbonates, which suggest the involvement of localized fluxes of hydrothermal fluids during its formation during Paleozoic orogenesis. Geochemical proxies suggest that in both age groups the diagenetic fluids were originally of coeval seawater composition, subsequently modified via water-rock interaction possibly related to brines, which were modified by the dissolution of Silurian evaporites from the Salina series. The integration of the obtained data in the present study demonstrates the linkage between fluid flux history, fluid compartmentalization, and related diagenesis during the regional tectonic evolution of the Michigan Basin.

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An Integrated Study of Water Weakening and Fluid Rock Interaction Processes in Porous Rocks: Linking Mechanical Behavior to Surface Properties

Applied Sciences ◽

10.3390/app112311437 ◽

2021 ◽

Vol 11 (23) ◽

pp. 11437

Author(s):

Davide Geremia ◽

Christian David ◽

Rachid Ismail ◽

Alae El Haitami

Keyword(s):

Surface Energy ◽

Mechanical Behavior ◽

Young’S Modulus ◽

Critical Pressure ◽

Young's Modulus ◽

Fluid Composition ◽

Porous Rocks ◽

Rock Interaction ◽

Repulsive Forces ◽

The Impact

We investigated the impact of water weakening on the mechanical behavior of Obourg Chalk and Ciply Chalk (Mons Basin, Belgium). Different mechanical tests were conducted to estimate the unconfined compressive strength (UCS), tensile strength, Young’s modulus, mechanical strength under triaxial loading, critical pressure, fracture toughness, cohesion, and internal friction coefficient on samples either dry or saturated with water or brine. This extensive dataset allowed us to calculate wet-to-dry ratios (WDR), i.e., the ratio between any property for a dry sample to that for the water-saturated sample. For both chalks, we found that water has a strong weakening effect with WDR ranging from 0.4 to 0.75. Ciply Chalk exhibits more water weakening than Obourg Chalk. The highest water weakening effect was obtained for UCS, critical pressure, and Young’s modulus. Weakening effects are still present in brine-saturated samples but their magnitude depends on the fluid composition. The mechanical data were correlated to variations in surface energy derived from three different methods: fracture mechanics, contact angle goniometry, and atomic force microscopy. Water weakening in the tested chalks can be explained by a clear reduction in surface energy and by the existence of repulsive forces which lower the cohesion.

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Conversion of lacZ Enhancer Trap Lines to GAL4 Lines Using Targeted Transposition in Drosophila melanogaster

Genetics ◽

10.1093/genetics/151.3.1093 ◽

1999 ◽

Vol 151 (3) ◽

pp. 1093-1101 ◽

Cited By ~ 1

Author(s):

Katharine J Sepp ◽

Vanessa J Auld

Keyword(s):

Expression System ◽

Enhancer Trap ◽

P Element ◽

Specific Expression ◽

Complete Replacement ◽

New Genes ◽

Biological Studies ◽

Gal4 Expression ◽

Element Mobilization ◽

Low Efficiency

Abstract Since the development of the enhancer trap technique, many large libraries of nuclear localized lacZ P-element stocks have been generated. These lines can lend themselves to the molecular and biological characterization of new genes. However they are not as useful for the study of development of cellular morphologies. With the advent of the GAL4 expression system, enhancer traps have a far greater potential for utility in biological studies. Yet generation of GAL4 lines by standard random mobilization has been reported to have a low efficiency. To avoid this problem we have employed targeted transposition to generate glial-specific GAL4 lines for the study of glial cellular development. Targeted transposition is the precise exchange of one P element for another. We report the successful and complete replacement of two glial enhancer trap P[lacZ, ry+] elements with the P[GAL4, w+] element. The frequencies of transposition to the target loci were 1.3% and 0.4%. We have thus found it more efficient to generate GAL4 lines from preexisting P-element lines than to obtain tissue-specific expression of GAL4 by random P-element mobilization. It is likely that similar screens can be performed to convert many other P-element lines to the GAL4 system.

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