Hydrogeology of desert springs in the Panamint Range,California, USA: Geologic controls on the geochemical kinetics,flowpaths, and mean residence times of springs

Over 180 springs emerge in the Panamint Range near Death Valley National Park, CA, yet, these springs have received very little hydrogeological attention despite their cultural, historical, and ecological importance. Here, we address the following questions: (1) which rock units support groundwater flow to springs in the Panamint Range, (2) what are the geochemical kinetics of these aquifers, and (3) and what are the residence times of these springs? All springs are at least partly supported by recharge in and flow through dolomitic units, namely, the Noonday Dolomite, Kingston Peak Formation, and Johnnie Formation. Thus, the geochemical composition of springs can largely be explained by dedolomitization: the dissolution of dolomite and gypsum with concurrent precipitation of calcite. However, interactions with hydrothermal deposits have likely influenced the geochemical composition of Thorndike Spring, Uppermost Spring, Hanaupah Canyon springs, and Trail Canyon springs. Faults are important controls on spring emergence. Seventeen of twenty-one sampled springs emerge at faults (13 emerge at low-angle detachment faults). On the eastern side of the Panamint Range, springs emerge where low-angle faults intersect nearly vertical Late Proterozoic, Cambrian, and Ordovician sedimentary units. These geologic units are not present on the western side of the Panamint Range. Instead, springs on the west side emerge where low-angle faults intersect Cenozoic breccias and fanglomerates. Mean residence times of springs range from 33 (±30) to 1,829 (±613) years. A total of 11 springs have relatively short mean residence times less than 500 years, whereas seven springs have mean residence times greater than 1,000 years. We infer that the Panamint Range springs are extremely vulnerable to climate change due to their dependence on local recharge, disconnection from regional groundwater flow (Death Valley Regional Flow System - DVRFS), and relatively short mean residence times as compared with springs that are supported by the DVRFS (e.g., springs in Ash Meadows National Wildlife Refuge). In fact, four springs were not flowing during this campaign, yet they were flowing in the 1990s and 2000s.     

Petrology and geothermometry of retrograded Hercynian charnockites and host gneisses, Agly Massif, French Pyrenees

Abstract A Hercynian charnockite occurs within high-grade gneisses in the Agly Massif, French Pyrenees. Its thermal history has been evaluated using the Fe-Mg distribution coefticient ( K _D) between garnet and biotite. These minerals have different origins but similar compositions in the charnockites and host gneisses. In the charnockite, the Bi–Ga pairs are the retrograde products of Opx alteration. This Opx reaction with feldspar can be written. Opx + PI + Fluid 1(H₂O + Al + K + Fe + Ti) = Bi + Ga + Q + Fluid 2(H₂O + Na). The garnets are relatively Ca poor (4–2.5% grossular); they are automorphic and zoned in the gneisses and poikiloblastic in the charnockites. Both types show a retrograde rim (of few hundred microns'width) across which Fe and Mn increase as Mg decreases. The biotites show a good correlation between the octahedral cations (Ti⁴⁺+ Fe²⁺) and (Mg²⁺+ Al³⁺_VI); Ti and Fe both increase, whereas Mg and Al_VI decrease. There is an inverse linear correlation between Fe²⁺ and Mg²⁺ and the Fe/Mg ratio increases as Ti increases. The relation between Ti and K ^Ga-Bi_DFe-Mg is less clear: it seems that K _D slightly decreases as Ti increases. The equilibration temperatures of Ga–Bi pairs are discussed: the charnockite Ga-Bi pairs have equilibrated between 550°C and 600°C; whereas those of the gneisses have equilibrated between 550°C and 650°C. Two main thermal steps appear: one in the gneisses between 600-650°C and a second one in both the gneisses and the charnockites between 550°C and 600°C.     

吐哈盆地丘东次凹低熟气的生成与动力学研究

采用黄金管—高压釜封闭体系,对吐哈盆地艾试1井的泥岩和煤岩进行了低温热解实验。根据实验结果,分别求取了干气（C1）、湿气（C2～C5）生成过程的初始动力学参数,然后将单一活化能的动力学参数进一步优化为具有高斯分布的活化能,优化后的动力学参数能较好拟合实验数据。利用优化后的动力学模型模拟了吐哈盆地丘东凹陷八道湾组天然气早期生成过程,并将模拟结果与实际地质资料进行了对比。结果表明,经过优化后的低温恒温热解动力学,能有效评价早期生气过程;在丘东次陷发现的天然气,与八道湾组源岩关系密切。     

环境矿物界面反应动力学

环境矿物界面反应动力学主要探讨地表中各种有毒、有害离子或分子与矿物表面之间的反应速率与反应机制。矿物表面存在一组化学活性很强的表面功能基，当它们与环境中毒害物质发生作用时，会因其极性、荷电性和Lewis酸碱性不同而表现出不同的作用力和反应速率，进而控制有毒、有害物质在大气、水体和沉积物中的赋存形态，稳定性及迁移转化速率。本文简要介绍了环境矿物界面反应动力学理论，并给出几个应用实例。     

砂岩储层中原油微生物降解的模拟实验研究

模拟辽河冷东-雷家地区的砂砾岩储层条件，采用该地区的正常原油，在３０℃恒温和充氧下以及有营养元素的水溶液中，进行了原油喜氧微生物降解实验。实验表明，经微生物降解后，原油的化学组成发生了较大变化，饱和烃含量下降，沥青质、非烃含量上升；水溶液的ｐＨ值下降，并在其中检测出了有机酸，可见在微生物的代谢过程中，原油中的烃类分子被部分转化为水溶性含氧酸性产物。降解实验的油样与取自同一地区的两个重质原油饱和烃气相色谱图比较，两者在组成上极其相近，其结果说明辽河油田的重油成因，是原油遭受了喜氧微生物的降解。实验对微生物降解过程的动力学进行了初步研究。微生物对饱和烃馏分中不同化合物的降解序列为:短链正构烷烃、长链正构烷烃、异构烷烃、环状烷烃。但当各组分间的浓度发生较大变化时，降解序列会有所不同。     

玄武岩—水相互作用的溶解机理研究

在常温常压排除大气干扰的封闭体系条件下,将一定粒度的玄武岩样品浸泡在不同酸度的水溶液里,研究玄武岩－水相互作用过程中元素释放和溶液酸度的变化情况。结果发现：（１）经过一段时间后,溶液中主要元素的浓度趋向平衡;（２）溶液酸度发生明显变化,即不论反应初始溶液是碱性的还是酸性的,最终都将趋于中性,我们把此现象称为溶液的中性化效应。根据溶液中溶解组分的浓度和样品表面组成的ＸＰＳ测定结果,提出玄武岩在碱性和酸性溶液中不同的溶解机理。     

The dissolution kinetics of atacamite in the acid range and the stability of atacamite containing soils from Namaqualand,South Africa

The Cu hydroxy mineral, atacamite, is commonly associated with saline environments and is generally thought to dissolve rapidly in the presence of fresh water. A Cu contaminated soil from the arid Namaqualand region, South Africa, shows atacamite as the dominant Cu containing mineral. The stability of the Cu phase in this soil was determined through equilibrium and leaching studies using both deionised water (DI) and a concentrated (0.5 M) NaCl solution. Initially a high concentration of exchangeable Cu was released from the soils leached with NaCl. Continued leaching with NaCl resulted in a substantial decrease in Cu release as atacamite equilibria started to control dissolved Cu. This suggests that an initial spike of Cu laden water will leach from the soils at the onset of a large rainfall event. Further additions of water will result in a lower but sustained release of Cu from the soil. The Cu contaminated soils are exposed to acidic sulphate leachate thus the dissolution kinetics of synthetic atacamite in the acidic range (pH 5.5–4.0) was determined in both NaCl and DI solutions. The kinetic data showed that atacamite dissolution rates are significantly higher in DI than in NaCl but the rates converge at pH 4. In comparison to common acid soluble minerals, atacamite displays a moderate dissolution rate (10^−9.55–10^−7.14 mol m⁻² s⁻¹) within the acid range (pH 5.5–4.0). The atacamite dissolution reaction order with respect to pH is 1.3 and 1.6 in DI and NaCl solutions, respectively, suggesting that dissolution rates of atacamite are highly pH dependent in the acid range. The type of acid used to lower the pH had no effect on the reaction kinetics, with HNO₃ and H₂SO₄ resulting in comparable dissolution rates of atacamite at pH 4.5.     

Petroleum generation characteristics of heterogeneous source rock from Chia Gara formation in the Kurdistan region,northern Iraq as inferred by bulk and quantitative pyrolysis techniques

This study is the first attempt which provides information regarding the bulk and quantitative pyrolysis results of the Chia Gara Formation from the Kurdistan region, northern Iraq. Ten representative early-mature to mature samples from the Chia Gara Formation were investigated for TOC contents, Rock Eval pyrolysis, pyrolysis-GC and bulk kinetic parameters. These analyses were used to characterize the petroleum generated during thermal maturation of the Chia Gara source rock and to clarify the quantity of the organic matter and its effect on the timing of petroleum generation.Pyrolysis HI data identified two organic facies with different petroleum generation characteristics; Type II–III kerogen with HI values of >250 mg HC/g TOC, and Type III kerogen with HI values < 100 mg HC/g TOC. These types of kerogen can generate liquid HCs and gas. This is supported by the products of pyrolysis–gas chromatography (Py–GC) analysis of the extracted rock samples. Pyrolysis products show a dominance of a marine organic matter with variable contributions from terrestrial organic matter (Types II–III and III kerogen), and produces mainly paraffinic-naphthenic-aromatic low wax oils with condensate and gas.Bulk kinetic analysis of the Chia Gara source rock indicates a heterogeneous organic matter assemblage, typical of restricted marine environments in general. The activation energy distributions reveal relatively broad and high values, ranging from 40 to 64 kcal/mol with pre-exponential factors varying from 2.2835 E+12/sec to 4.0920 E+13/sec. The predicted petroleum formation temperature of onset (TR 10%) temperatures ranges from 110 to 135 °C, and peak generation temperatures (geological T_max) between 137 °C and 152 °C. The peak generation temperatures reach a transformation ratio in the range of 42–50% TR, thus the Chia Gara source rock could have generated and expelled significant quantities of petroleum hydrocarbons in the Kurdistan of Iraq.     

海绵铁对活性艳红K-2BP废水的脱色动力学研究

为了开发新型的脱色填料,进行海绵铁对活性艳红K-2BP的脱色动力学研究。试验结果表明,海绵铁对活性艳红K-2BP具有较高的脱色率,在10min,30min和60min脱色率分别为58.78%,85.2%和93.89%。在海绵铁表面衰减分析的基础上,建立了脱色动力学模型,并研究了pH值、温度、粒径和投加量对反应速度常数K和表面衰减系数Ka的影响。     

海洋浮游生物氮吸收动力学及其粒级特征

于１９９１年秋－１９９２年夏在中国科学院生态网络站之一的胶州湾进行了４个季节的现场实验，运用＾１５Ｎ同位素示踪方法研究胶州湾浮游生物群落对两种主要源铵态氮和硝态氮的吸收动力学及其粒级特征。研究初步阐明自然浮游生物落在不同季节，对不同氮源的吸收特性和受控机制，首次在群落水平上给出不同粒级浮游生物氮吸收特征的定量描述，从而为新生产力研究，生态系能流分配和生源要素生物地化循环研究提供重要参数。