The Hiendelaencina mining district (Guadalajara,Spain)

The Hiendelaencina mining district (Guadalajara, Spain), includes the ore deposits of the Hiendelaencina, La Bodera and Congostrina areas. In this paper a general overview of this district is given, with special emphasis on the parageneses, mineralizing stages and chemical characteristics of the sulphides and sulphosalts. These deposits contain silver in Sb-rich sulphosalts such as freibergite, pyrargyrite, polybasite, stephanite, freieslebenite and the Bi-rich sulphosalt, aramayoite. Three mineralizing stages have been detected in Hiendelaencina and Congostrina: (1) As-Fe; (2) Cu-Zn-Fe-Sb-Ag; and (3) Pb-Sb-Ag (±Bi) but only two in La Bodera (stages 2 and 3). The average sulphosalt formulas are: freibergite (Cu_0.5 Ag_5.9) (Fe_1.42 Zn_0.66) (Sb_4.49 As_0.02) S₁₃; pyrargyrite Ag_3.38 Sb_1.0 S₃; polybasite (Ag_16.3Cu_0.15) (Sb_2.8 As_0.15) S₁₁; stephanite Ag_6.7 Sb_1.38 S₄; freieslebenite Ag_1.1 Sb_0.83 Pb_1.05 S₃ and aramayoite Ag_1.06 Bi_{0. 35} Sb_0.7 Pb_0.03 S₂. The compositional patterns of these sulphosalts (mainly based on the Sb/(Sb + Ag), Ag/ (Ag + Cu), Sb(Ag + As) and Ag/(Ag + Cu) ratios) are outlined, pointing broadly to similar tendencies in their chemistry and genetic conditions.     

The Hiendelaencina epithermal silver-base metal district,Central Spain: Tectonic and mineralizing processes

The northeastern sector of the Spanish Central System hosts important Stephanian-Permian silver-base metal epithermal mineralizations defining the so-called Hiendelaencina District. The overall geotectonic evolution of this region indicates a major late Variscan extensional period involving the unroofing of dome-shaped metamorphic core complexes, which ultimately led to the radial brittle disruption of these bodies allowing the ascent of andesitic magmas and high-level hydrothermal activity. The deposits are hosted by high-grade metaphorphic rocks belonging to these complexes. Mineralogical and fluid inclusion studies reveal that the mineralizations were formed during two to four hydrothermal stages. These are the result of complex interactions between fluids of contrasted temperatures and salinities. Data on sulphur isotopes suggest that two sources of sulphur existed: magmatic (andesitic derived, with ³⁴S + 6) and metasediment-derived (with initial ³⁴S probably + 25).     

Trondhjemites in the Badajoz-Cordoba belt,Sw Spain. Geochemical interpretations and geological implications

Several banded bodies of the Valencia de las Torres Formation in the Azuaga Group (Badajoz-Cordoba axis) are defined as trondhjemites. Principal component analysis of major elements shows that the chemical variability of the samples is compatible with a single differentiation process. Systematic study of their petrography and chemistry points to trondhjemite-tonalite series belonging to high grade metamorphic belts and their generation is postulated as being due to partial melting of a tholeite in a subduction zone, for which a hercynian age is suggested.

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Zusammenfassung Mehrere gebänderte Gesteinskörper innerhalb der Valencia de las Torres-Formation der Azuaga Gruppe (Badajoz-Cordoba-Achse) werden als Trondheimite interpretiert. Eine chemische Analyse der wichtigsten Elemente der Proben bestätigt, daß die Variabilität im Chemismus mit einem einzigen Differentiationsvorgang erklärbar ist. Die systematische petrographische und chemische Analyse deutet auf eine Trondheimite-Tonalität Abfolge, die hochmetamorphen Gürteln zugeordnet wird. Ihre Entstehung wird auf teilweises Schmelzen eines Tholeites in einer Subduktionszone herzynischen Alters zurückgeführt.

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Résumén Diversos cuerpos bandeados de la Formación Valencia de las Torres en el Grupo de Azuaga (Eje Badajoz-Córdoba) se definen como trondhjemitas. Del Anâlisis de Componentes Principales sobre elementos mayores se desprende que la variabilidad química de las muestras es compatible con un sólo proceso de diferenciación. El estudio sistemâtico de sus caracteres petrográficos y químicos pone de manifiesto su relación con series trondhjemítico-tonalíticas propias de cinturones metamórficos de alto grado y, coherentemente, se postula su generación por fusión parcial de una tholeta en una zona de subducción, para la cual, de acuerdo con los datos geocronológicos disponibles se sugiere una edad hercínica.

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Valencia de la Torres Azuaga ( Badajoz-Cordoba) , . , . , , , - . .

     

江西省船坑铜矿成矿岩体地球化学特征、锆石U-Pb定年及地质意义

分析了船坑铜矿成矿岩体石英闪长玢岩主微量、稀土元素特征及锆石U-Pb测年数据,表明岩石具高钾偏铝质I型花岗岩特征,及岛弧成因岩浆特点;锆石稀土元素表明有地壳物质的加入,属壳幔混源。锆石U-Pb年龄162.9±3.6Ma,大致代表含矿岩体成岩年龄。该矿床形成于钦杭成矿带铜矿主成矿期,处于岩石圈拆沉或伸展-减薄的构造环境,受太平洋板块往欧亚大陆的俯冲的影响。     

Hydrogeology and hydrogeochemistry at a site of strategic importance: the Pareja Limno-reservoir drainage basin (Guadalajara,central Spain)

A small calcareous basin in central Spain was studied to establish the role of groundwater in the Pareja Limno-reservoir. Limno-reservoirs aim to preserve a constant water level in the riverine zone of large reservoirs to mitigate the impacts arising from their construction. Groundwater flow contribution (mean 60 %) was derived by recharge estimation. In situ measurements (spring discharge, electrical conductivity and sulfate) were undertaken and spring discharge was compared with a drought index. Twenty-eight springs were monitored and three hydrogeological units (HGUs) were defined: a carbonate plateau (HGU1), the underlying aquitard (HGU2), and the gypsum-enriched HGU3. HGU1 is the main aquifer and may play a role in the preservation of the limno-reservoir water level. Hydrogeochemical sampling was conducted and the code PHREEQC used to describe the main geochemical processes. Weathering and dissolution of calcite and gypsum seem to control the hydrogeochemical processes in the basin. Water progresses from Ca²⁺–HCO₃ ^– in the upper basin to Ca²⁺–SO₄ ^2– in the lower basin, where HGU3 outcrops. A clear temporal pattern was observed in the limno-reservoir, with salinity decreasing in winter and increasing in summer. This variation was wider at the river outlet, but the mixing of the river discharge with limno-reservoir water buffered it.     

Geology and rural landscapes in central Spain (Guadalajara, Castilla—La Mancha)

Methods commonly used in regional geological analysis were employed to study the visual landscapes of the Sigüenza–Molina de Aragón area (Spain). Landscape data were compiled to produce a landscape map and a photograph catalogue. Lithological composition, tectonic structure and recent erosive processes are the main factors controlling the visual landscapes. Territorial properties, such as colours and agricultural capacities, are controlled by these geological characteristics. The landscape map and the photographic catalogue is the main contribution of this paper. The first level of landscape classification distinguishes zones with dominance of either flat, concave or convex areas. Other parts of the territory are, however, composed of concave and convex combinations that originate hybrid orographic structures. In a second level of classification, several subdivisions for each of these types are established.     

Geochemical and mineralogical evidence for Sahara and Sahel dust additions to Quaternary soils on Lanzarote,eastern Canary Islands,Spain

Africa is the most important source of dust in the world today, and dust storms are frequent on the nearby Canary Islands. Previous workers have inferred that the Sahara is the most important source of dust to Canary Islands soils, with little contribution from the Sahel region. Soils overlying a late Quaternary basalt flow on Lanzarote, Canary Islands, contain, in addition to volcanic minerals, quartz and mica, exotic to the island’s bedrock. Kaolinite in the soils also likely has an exotic origin. Trace‐element geochemistry shows that the soils are derived from varying proportions of locally derived basalt and African dust. Major‐element geochemistry, clay mineralogy and interpretation of satellite imagery suggest that dust additions to the Canary Islands come not only from the Sahara Desert, but also from the Sahel region.     

河南桐柏围山城金银成矿带矿床地球化学特征

根据对围山城金银成矿带的成矿元素、黄铁矿微量元素标型特征、成矿流体地球化学特征、稀土元素、硫铅同位素和氢氧同位素特征的研究,提出矿带中的初始成矿物质主要来源下地壳和上地幔,由海底火山喷流作用形成.各工业矿体的形成与后期叠加构造和热流体的改造作用密切相关.     

New discoveries of vertebrate remains from the Triassic of Riba de Santiuste,Guadalajara (Spain)

The palaeontological sites of Riba de Santiuste and Sienes (Riba de Santiuste area) are located in the province of Guadalajara, Spain. They include a stratigraphic interval in Muschelkalk facies belonging to the “Cuesta del Castillo Sandstones” Formation and “Royuela Dolostones, Marls and Mudstones” Formation. These sites include numerous fossil plants, direct vertebrate remains, and vertebrate swim traces. The vertebrate remains correspond to a multitude of anatomical elements of Sauropterygia (Nothosauroidea, Placodontia) and possible Archosauria (Rauisuchia) remains. The fossil material attributed to nothosaurs includes teeth, coracoids, a thoracic vertebra, some isolated vertebral centra, humerus, rib fragments, and some dorsal and caudal vertebrae. The remains attributed to placodonts correspond to fragments of skull, quadrate, teeth and osteoderms. Other undetermined sauropterygian remains, such as ulnas, fragments of long bones, fragments of ribs, and articular facets of ribs have been also recovered. Additionally, a fragment of mandible and an intervertebral disk of indeterminate reptiles whose size could be compatible with archosaurs are also described. These bones are exceptionally well-preserved because the fossilization processes have preserved the microstructure of the tissues. The sites also show vertebrate traces, with parallel scratch impressions interpreted as swim traces. The relative stratigraphic position and the palaeontological content of these sites suggest a Ladinian age (Middle Triassic). The interpretation of the sedimentary facies here described also suggests that the sites could correspond to detrital-carbonate mixed deposits of coastal intertidal to supratidal environments.     

Sedimentology of Quaternary perched springline and paludal tufas: criteria for recognition, with examples from Guadalajara Province, Spain

Outcrop‐scale geometries and bed relationships of ambient temperature freshwater carbonates are poorly understood because many described tufas have been dismantled by erosion and present only part of a particular depositional model. At the field scale, four end‐member models encompass the tufa continuum: (1) perched springline; (2) paludal; (3) fluvial; and (4) lacustrine tufas. Individual bed types can occur with variable dominance within several of these models, but one or more beds are characteristically dominant only within a single tufa model, so it can be differentiated from relatively isolated outcrop fragments. Two models (perched springline tufas and paludal tufas) are known in outline only in the literature despite being present within the Quaternary deposits of most karstic regions. Perched springline tufas generally form lobate, fan‐shaped mound morphologies on hillslopes and develop from single or multiple spring resurgences. Mature deposits show a subhorizontal top and a steep face on the downflow side. The steep outer zones of tufa mounds may be developed into cascades with moss curtains or can be dominated by shallow rimstone pools according to face angle. Tufa deposits lying downslope of the mounds are usually detrital in nature, especially if some dismantling of the mound has occurred. The relatively thin subhorizontal lobe‐top deposits commonly contain organic‐rich deposits. Paludal tufas develop predominantly in waterlogged valley bottom situations, where line‐sourced waters emerge from valley side and bottom aquifers. Lime mud precipitation predominates in these sites. Mud is deposited as subhorizontal laminites that thin towards the valley axis and downstream of resurgences. Tufa spring‐mounds may form where lesser volumes of water are involved. Individual tussocks (phytoherm cushions) of grasses and rushes are the most diagnostic feature of the model, but sapropels and peats may be intercalated. Diagenesis in both models is rapid. Lithification of individual beds is virtually instantaneous and always occurs before the decay of the associated living vegetation. The resulting highly porous and permeable fabrics remain fresh in Holocene tufas, but aggrading neomorphism and partial spar infill of vegetation moulds is common in older deposits. Dissolution in many perched springline tufas is small scale. Many large cavities are primary, but with later coatings of speleothems. Early removal of organics from paludal tufas is responsible for autobrecciation and differential compaction.     

大乌苏地区水系沉积物测量地球化学特征及成矿预测

文章在1∶50 000水系沉积物测量的基础上,分析了大乌苏地区的地球化学特征。通过对成矿元素的分布特征及相关性分析、因子分析,认为寻找铁、钒、钛、金矿床或矿化体潜力较大;根据异常特征及成矿地质条件,认为该区的成矿类型是与花岗岩有关的金矿和与玛尼吐组火山岩有关的铁、钒、钛多金属矿,进而划分出4个成矿远景区,即乌鲁喀马河、希里尼河金成矿远景区和碧洲镇、库依希罕河铁、钒、钛多金属成矿远景区。     

Geochemical patterns in soils of the karst region,Croatia

Soil samples were collected at 420 locations in a 5-km grid pattern in the Istria and Gorski Kotar areas of Croatia, and on the Croatian islands of Cres, Rab and Krk, in order to relate geochemical variation in the soils to underlying differences in geology, bedrock lithology, soil type, environment and natural versus anthropogenic influences. Specific objectives included assessment of possible agricultural and industrial sources of contamination, especially from airborne effluent emitted by a local power plant. The study also tested the adequacy of a fixed-depth soil sampling procedure developed for meager karstic soils. Although 40 geochemical variables were analyzed, only 15 elements and 5 radionuclides are common to all the sample locations. These elements can be divided into three groups: (1) those of mostly anthropogenic origin — Pb, V, Cu and Cr; (2) those of mixed origin — radionuclides and Zn; and (3) those of mostly geogene origin — Ba, Sr, Ti, Al, Na, Ca, Mg, Fe, Mn, Ni and Co. Variation in Pb shows a strong correlation with the pattern of road traffic in Istria. The distributions of Ca, Na and Mg in the flysch basins of southern Istria and Slovenia are clearly distinguishable from the distributions of these elements in the surrounding carbonate terrains, a consequence of differences in bedrock permeability, type of drainage and pH. The spatial pattern of ¹³⁷Cs from the Chernobyl nuclear power plant accident reflects almost exclusively the precipitation in Istria during the days immediately after the explosion.     

二连盆地川井坳陷铀成矿环境及成矿有利地段研究

本在简述二连盆地川井坳陷区域地质，区域水地质特征的基础上，重点阐述了白晋系岩性岩相特点，岩石后生蚀变和铀矿化特征，并得出坳陷在纵横两方向上存在着较大的分割性和不均匀性，白音查干凹陷砂体属三角洲相叠加了河流相的新认识，进而提出了下白垩统为湖相→三角洲相→河流相的连续演化系列。从宏观，微观两方面论述了白音查干凹陷潜水和层间氧化带砂岩型铀矿成矿前景，同时，分片对整个川井坳陷成矿有利及不利因素作了评价，在对古河道发育情况，基底，构造，水地质和后生蚀变，有机质等成矿条件分析的基础上，得出川井坳陷东部桑根达来凹陷西南缘为古河道砂岩型铀矿成矿有利地段的结论。     

Local people unprotected by protected (depopulated) natural areas: the case of Sierra Norte Guadalajara,Spain

The aim of this study is to place the current geographical debate on nature in the context of protected natural areas severely affected by depopulation processes, in which the daily lives of the inhabitants have been altered by changes in the traditional balance between human and non-human populations. A significantly humanized area within the Sierra Norte de Guadalajara National Park in central Spain is considered as an example. The qualitative methodology followed is based on documentary analysis and interviews with key inhabitants in the area, revealing narratives with a productive or consumer view of the nature. The national park appears as a container of a cultural nature, initially created by the traditional inhabitants, which generates an artificial, excessive nature and accelerates regressive sociodemographic dynamics.     

A Geochemical study of the groundwater in the Misli basin and environmental implications

The aim of this study was to determine geochemical properties of groundwater and thermal water in the Misli Basin and to assess thermal water intrusion into shallow groundwater due to over-extraction. According to isotope and hydrochemical analyses results, sampled waters can be divided into three groups: cold, thermal, and mixed waters. Only a few waters reach water–rock chemical equilibrium. Thermal waters in the area are characterized by Na⁺–Cl⁻–HCO₃⁻, while the cold waters by CaHCO₃ facies. On the basis of isotope results, thermal waters in the Misli basin are meteoric origin. In particular, δ¹⁸O and δ²H values of shallow groundwater vary from −10.2 to −12.2‰ and −71.2 to −82‰, while those of thermal waters range from −7.8 to −10.1‰ and from −67 to −74‰, respectively. The tritium values of shallow groundwater having short circulation as young waters coming from wells that range from 30 to 70 m in depth vary from 10 to 14 TU. The average tritium activity of groundwater in depths more than 100 m is 1.59 ± 1.16, which indicates long circulation. The rapid infiltration of the precipitation, the recycling of the evaporated irrigation water, the influence of thermal fluids and the heterogeneity of the aquifer make it difficult to determine groundwater quality changes in the Misli Basin. Obtained results show that further lowering of the groundwater table by over-consumption will cause further intrusion of thermal water which resulted in high mineral content into the fresh groundwater aquifer. Because of this phenomenon, the concentrations of some chemical components which impairs water quality in terms of irrigation purposes in shallow groundwaters, such as Na⁺, B, and Cl⁻, are highy probably expected to increase in time.     

安徽黟县富硒土壤地球化学特征研究

通过开展黟县土地质量地球化学调查与富硒资源评价,查明黟县表层土壤硒元素平均值为0.523mg/kg,高于富硒土壤标准,相对于全国及安徽省江淮流域硒含量表现为富集特征;参照《天然富硒土地划定与标识》（试行）（DD 2019—10）圈定富硒土壤168.61km2,占调查区总面积的20.94%。通过分析硒元素在不同土壤类型及成土母质的分布特征,认为区内富硒土壤成因可分为两大类：(1)硒高背景岩石风化形成的富硒土壤;(2)土壤黏土矿物及有机质表层次生富集作用形成的富硒土壤。     

新疆阿尔泰东部新生代玄武岩的地球化学特征与地质意义

新疆阿尔泰东部哈拉乔拉出露有新生代玄武岩,K—Ar法测得玄武岩的年龄在10～20Ma,地球化学分析结果表明哈拉乔拉玄武岩具有高TiO2含量、高钾富碱的特点,属于典型的橄榄玄粗岩系列;强烈富集不相容元素和轻稀土元素,显示出源区富集的特点。（^87Sr/^86Sr）．为0．704432～0．704538,（^143Nd／^144Nd）i为0．512641～0．512779,εNd（t）为0．29～1．03,其Sr-Nd同住素特征和地球化学特征都与洋岛玄武岩（OIB）相似。La／Nb（0．765～0．823）、Nb／U（35．02～52．01）等不相容元素的比值指示了源区中可能存在少量循环地壳物质。综合对比南天山托云等地区新生代玄武岩,中亚地区的地球化学性质相似的新生代火山岩分布零星,空间上与大型断裂相对应,不应是前人地幔柱成因的观点。本文结合中亚地区古生代地壳的演化特点,提出中亚地区的新生代类OIB型玄武岩来源于中亚地区已被改造的富集地幔。     

山东蒙阴科马提岩地球化学特征及其意义

山东蒙阴科马提岩具有典型的鬣刺结构，高镁低钛，铝不亏损，具有正的Rb、Ba、Sr、U异常，轻稀土元素亏损，重稀土元素平坦，稀土元素总量很低，高场强元素与稀土元素发生分异，Nb/Nb^＊〉1，与加拿大蒙罗镇科马提岩地球化学特征和同位素特征相似。研究表明，蒙阴科马提岩可能起源于长期亏损的地幔源区，岩浆不可能来源于以橄榄石、辉石和石榴石（或者majorite）为主要矿物相的地幔源区。最新Sm-Nd同位素研究显示，蒙阴科马提岩样品的εNd值为-0．4～＋3．6，新鲜样品一般为＋3．3，也证实了科马提岩来自长期亏损的地幔源区，并且地幔柱在上升过程中受到地壳混染程度很小，推测研究区科马提岩的喷出可能是新太古代大陆增生事件的重要组成部分。