A Critical Appraisal of Field Evidence From A Regional Survey for Acid Deposition Effects On Scottish Moorland Podzols

Samples have been collected from major horizons of 34 podzol profiles distributed throughout Scotland, all developed from granite or granitic tills and under Calluna moorland. the pH in water and calcium chloride pastes, exchangeable cations and cation exchange capacity, and extractable aluminium of the soils collected have been measured, and the results studied in relation to reported atmospheric deposition of H⁺, non-marine sulphur and nitrate. for all horizons, significant positive correlations were found between soil pH and rainfall mean pH, as might be expected when the critical load of H⁺ deposition is exceeded. Acidifying pollutant deposition also apparently increased soil extractable aluminium concentrations in the B and C horizons. However, exchangeable base cation concentrations tended to increase, rather than decrease, with increasing precipitation acidity. This effect was attributed to increases in biogeochemical cycling of base cations, increases in leaching inputs of base cations from overlying A/E horizon soils, and increases in the inputs of base cations leached from upslope. the results suggest that the simple steady state mass approach to the quantification of critical loads, as often applied, may be an oversimplification.     

湖南郴县千里山花岗岩的岩石学特征

千里山花岗岩是一个与W、Sn、Mo、Bi多金属矿床有关的多期多阶段岩浆侵入体。燕山晚期的花岗斑岩,其矿物学、岩石学及地球化学等各项特征均与燕山早期花岗岩及其衍生岩脉的特征不相同,W、Sn、Mo、Bi矿化与早期花岗岩体有关而与晚期花岗斑岩无成因联系,主体期花岗岩应属改造型,其成岩温度约在700℃±,压力约为1千巴,fo_2=10~(-15.5)～10~(-17.0),fH_2o=135～815巴,有利于矽卡岩的形成。     

Activity concentrations and dose rates from decorative granite countertops

The gamma radiation emitted from a variety of commercial decorative granites available for use in U.S. homes has been measured with portable survey meters as well as an NaI(Th) gamma spectrometer. The ⁴⁰K, U-nat, and ²³²Th activity concentrations were determined using a full-spectrum analysis. The dose rates that would result from two different arrangements of decorative granite slabs as countertops were explored in simulations involving an adult anthropomorphic phantom.     

坡位对马尾松林下土壤理化性质、酶活性及微生物特性影响

以我国南方花岗岩区退化马尾松林地土壤为研究对象,通过典型样地调查方法研究不同坡位（坡上、坡中,坡底）马尾松对土壤理化性质、酶活性和微生物学性质的影响。结果表明,0～20和20～40 cm土层土壤w（有机质）、w（全氮）、w（碱解氮）和w（速效钾）坡位间差异均显著（p〈0.05）,其中w（有机质）和w（全氮）均表现为坡底〉坡中〉坡上;而w（全磷）和w（全钾）位间差异不显著;3坡位中坡底土壤w（粘粒）较高容重较小。土壤酶活性坡位间差异不显著,可能受林分密度影响较大。两土层微生物生物量碳氮与土壤呼吸强度均为坡底最大,且与有机质和全氮相关性分别达显著（p〈0.05）和极显著（p〈0.01）正相关,但在微生物对碳利用效率、有机碳氮累积程度等方面坡位间差异不显著。所以,对养分瘠薄且易受侵蚀的花岗岩红壤区域,马尾松作为恢复植被须谨慎选择。     

低压水射流辅助PDC刀具切削花岗岩

采用低压水射流辅助聚晶金刚石刀具车削花岗岩，采集不同切削条件下切削力的数据，分析了在水射流辅助下刀具进给量、切削深度、切削速度、水射流压力、喷射距离对切削力的影响。结果表明，在实验压力范围内，切削过程中，水射流使岩石受到冲蚀，并使微裂纹扩展，有利于岩石的切削。切削力随着水射流压力的增大而减少。     

Laboratory migration experiments with radionuclides and natural colloids in a granite fracture

Natural colloids in groundwater could facilitate radionuclide transport, provided the colloids are mobile, are present in sufficient concentrations and can adsorb radionuclides. This paper describes the results of a laboratory migration study carried out with combinations of radionuclides and natural colloids within a fracture in a large granite block to experimentally determine the impact of colloids on radionuclide transport. The 85Sr used in this study is an example of a moderately sorbing radionuclide, while the 241Am is typical of a strongly sorbed radionuclide with very low solubility. The natural colloids used in this study were isolated from granite groundwater from Atomic Energy of Canada (AECL) Underground Research Laboratory (URL), and consisted of mostly 1-10 nm organic colloids, along with lesser amounts of 10-450 nm colloids (organics and aluminosilicates). The measured coefficients for radionuclide sorption onto these colloids were between 3 x 10(2) and 1 x 10(3) ml/g for 85Sr, and between 7 x 10(4) and 7 x 10(5) mg/l for 241Am. The 85Sr sorption on the natural colloids appeared to be reversible. Migration experiments in the granite block were carried out by establishing a flow field between two boreholes (out of a total of nine) intersecting a main horizontal fracture. These experiments showed that dissolved 85Sr behaved as a moderately sorbing tracer, while dissolved 241Am was completely adsorbed by the fracture surfaces and showed no evidence of transport. However, when natural colloids were injected together with dissolved 241Am, a small amount of 241Am transport was observed, demonstrating the ability of natural colloids to facilitate the transport of radionuclides with low solubility. Natural colloids had only a minor effect on the transport of 85Sr. In a separate experiment to test the effect of higher colloid concentrations on 85Sr migration, synthetic colloids were produced from Avonlea bentonite. The introduction of a relatively high concentration of bentonite colloids actually reduced 85Sr transport because, compared to natural colloids, the bentonite colloids were less mobile and they sorbed 85Sr more strongly.     

The influence of colloid formation in a granite groundwater bentonite porewater mixing zone on radionuclide speciation

In the context of deep geological storage of high level nuclear waste the repository will be designed as multiple barrier system including bentonite as buffer/backfill material and the host rock formation as geological barrier. The engineered barrier (bentonite) will be in contact with the host rock formation and consequently it can be expected that bentonite porewater will mix with formation groundwater. We simulate in this study the mixing of Grimsel groundwater (glacial melt water) with synthetic Febex porewater (assuming already saturated state) in a batch-type study and investigate the formation of colloids by laser-induced breakdown detection (LIBD) and SEM-EDX as well as the changes in radionuclide (U, Th, Eu) speciation via ultrafiltration or via time-resolved laser fluorescence spectroscopy (TRLFS) analysis in the case of Cm(III). Based on PHREEQC saturation index (SI) calculations a precipitation of calcite might be expected at low Febex porewater (FPW) content (< 20%), fluorite precipitation at FPW contents < 60% and gibbsite precipitation at FPW contents above 10%. The colloids generated in the mixing zone aggregate when the synthetic FPW content exceeds 10%. LIBD analysis of the time-dependent colloid generation/aggregation revealed a low concentration of colloids to be stable with an estimated plateau value around 100–200 ppt and an average colloid diameter around 30 nm after 140 days reaction time at FPW admixture > 10%. SEM/EDX mostly identifies Al/Si containing colloidal phases and some sulfates could be found under certain admixture ratios. TRLFS studies show that the Cm speciation is strongly influenced by colloid formation in all solutions. In the Febex pore water/GGW mixing zone with high groundwater contents (> 80%) colloids are newly formed and Cm is almost quantitatively associated with most likely polysilicilic acid colloids.     

粤东花岗岩流域覆盖型风化壳风化特征比较

为了对比在同种基岩与气候背景下,相邻花岗岩流域风化壳的风化程度,借助粒度组成、pH值和磁化率等实验方法,测定了粤东榕江和漯河流域阶地上发育的冲积物覆盖型风化壳.数据结果说明,螺河流域发育的该类型风化壳的风化程度强于榕江流域阶地上发育的该类型风化壳.粒度组成还表明,两流域该类型风化壳具有在<2μm粒级含量上冲积层大于基座风化壳的特征.两个流域风化壳粒度组成差别的原因是两个流域不同的剥蚀速率,榕江流域剥蚀速率较快.pH值在冲积物覆盖型风化壳剖面上呈现三低两高间隔出现的规律.螺河流域风化壳磁化率低于榕江流域是由局部的地貌条件决定,磁化率在粤东地区该类型风化壳的指示意义不准确.     

浙东燕山晚期花岗岩的地球化学特征

浙东燕山晚期侵入岩分为I型和A型,本文研究了两个不同成因类型花岗岩的岩石化学、地球化学特征。A型花岗岩与I型花岗岩相比较,富硅、富碱、贫镁、贫钙、低铝,(Na+K)/Al(分子数)比值高,富Nb、Zr、Ga、F,而贫Sr、Ba、Cr、Ni、Co、V,Rb/Sr、Ga/Al比值高,LREE/HREE比值低,稀土元素球粒陨石标准化曲线为“V”型,δEu强烈亏损;是下地壳残留的麻粒岩相较低程度部分熔融或是早期部分熔融形成Ⅰ型岩浆之后残余的亏损物质部分熔融的产物。Ⅰ型花岗岩是由下地壳岩石部分熔融形成母岩浆,在岩浆上升过程中与中上陆壳物质发生混染和分离结晶而形成。