Deep Fractures Research Articles

Inverse modeling of ground surface uplift and pressure with iTOUGH-PEST and TOUGH-FLAC: The case of CO2 injection at In Salah, Algeria

Ground deformation, commonly observed in storage projects, carries useful information about processes occurring in the injection formation. The Krechba gas field at In Salah (Algeria) is one of the best-known sites for studying ground surface deformation during geological carbon storage. At this first industrial-scale on-shore CO2 demonstration project, satellite-based ground-deformation monitoring data of high quality are available and used to study the large-scale hydrological and geomechanical response of the system to injection. In this work, we carry out coupled fluid flow and geomechanical simulations to understand the uplift at three different CO2 injection wells (KB-501, KB-502, KB-503). Previous numerical studies focused on the KB-502 injection well, where a double-lobe uplift pattern has been observed in the ground-deformation data. The observed uplift patterns at KB-501 and KB-503 have single-lobe patterns, but they can also indicate a deep fracture zone mechanical response to the injection.The current study improves the previous modeling approach by introducing an injection reservoir and a fracture zone, both responding to a Mohr-Coulomb failure criterion. In addition, we model a stress-dependent permeability and bulk modulus, according to a dual continuum model. Mechanical and hydraulic properties are determined through inverse modeling by matching the simulated spatial and temporal evolution of uplift to InSAR observations as well as by matching simulated and measured pressures. The numerical simulations are in agreement with both spatial and temporal observations. The estimated values for the parameterized mechanical and hydraulic properties are in good agreement with previous numerical results. In addition, the formal joint inversion of hydrogeological and geomechanical data provides measures of the estimation uncertainty.

Architecture of the deep critical zone in the Río Icacos watershed (Luquillo Critical Zone Observatory, Puerto Rico) inferred from drilling and ground penetrating radar (GPR)

AbstractIn the critical zone, surficial bedrock interactions result in the formation of a mantle of chemically‐ and physically‐altered material defined here as regolith. In the watershed of the Río Icacos, an upland river draining the Luquillo Mountains in tropical Puerto Rico, we explored the influence of lithology (quartz diorite versus hornfels‐facies volcaniclastic rock) on weathering. Regolith profiles were studied by drilling boreholes and imaging the subsurface using ground penetrating radar (GPR). Overall, the regolith structure is not laterally continuous but rather is punctuated by zones of deep fractures that host in situ weathering, corestones, and colluvial material. GPR images of these vertical zones show reflectors at 15–20 m depth. Thus, the architecture of the critical zone in the upper Luquillo Mountains is highly dependent on lithology and its influence on fracture development. At the highest elevations where hornfels overlies quartz diorite, positive feedbacks occur when the water table drops so that oxidative weathering of biotite in the more felsic rock creates microfractures and allows deeper infiltration of meteoric waters. Such exposure results in some of the fastest weathering rocks in the world and may contribute to formation of the knickpoint in the Río Icacos watershed. This work represents the first study combining GPR and drilling to look at the structure of the deep critical zone and demonstrates: (1) the importance of combining direct methods (such as drilling) with indirect methods (such as GPR) to understand the architecture of the critical zone in tropical systems; (2) the interplay of the surficial stress regime, lithology and climate in dictating the architecture of weathering. Copyright © 2016 John Wiley & Sons, Ltd.

Specifics of Imaginative Approach in the US Documentary of 1960-2000s

The subject of this article is a survey of artistic techniques of the American documentary filmmaker F. Waisman. The object is the US documentary of the 1960-2000s. The author attempts to distinguish the specifics of the Waismans imaginative approach, exploring the directors work as a developed part of so-called observation method characteristic of the films by American documentary filmmakers R. Drew and R. Leacock (the founders of the direct cinema). The author shows that minimalism of expressive means, the frequent use of camera travellings, raw-like cutting in the movies Titicut Follies (1967), Hospital (1970), Near death (1989) greatly complicate the understanding of the Waismans concept. Ambiguity of imagery in these pictures inevitably leads to a richness of connotations and surplus symbolism. High school (1968) clearly demonstrates a deep fracture of the American society in the late 60's, fully reflected in the school system. Wiseman explores the nature of executive and judicial power of the US in Law and order (1969) and The juvenile court" (1973). He tries to show the crisis of classical art within mass culture in the films National gallery (2014) and Crazy Horse (2011). Waismans approach allows to avoid the commonplace discourse (and the decline in the artistic level of the film) in coverage of such phenomena as the executive and the judicial power, education, arts and entertainment industry. The director was able to combine the complex and polysemantic visual design with the unique composition of the stuff (through cutting and camera work). All this helped him to unite the imaginative merits of a documentary film with narrative symbolism and traditions of poetic cinema.

Analysis behaviour parametrs of intelligent metals and polymers under high speed loading

Almost investigated process parameters the behavior of materials under conditions of high load. It is found that the strength spheroplastic determined density and the geometrical parameters, the process of destruction and shows a direct relationship between the crack length and the amplitude of pulses at different loads. Experimentally proved that, depending on the rate of crack propagation in the materials group polymers may appear different fracture surfaces, "mirror" or "rough", and there is a parabolic or "The cup” kink. Established that at high speeds zones with different orientation. Proved that high performance load on intelligent materials leads to a deep fracture surfaces. The roughness increases with increasing speed of the crack. At speeds above 650 km / s is observed partial fragmentation pattern. Thus, the destruction of PMMA of interest in terms of the parameters of the spread of cracks and their rate of spread. According to the theoretical relationship between the critical pressure, causing the destruction of a spherical shell, and its parameters defined strength areas, mainly its geometrical characteristics, radius and wall thickness and elastic deformation of the glass. These data create the best design features durable, plastic and other properties because it has been proved that the basis of the effect of shape memory alloys are most of the so-called thermoelastic martensitic transformation. Almost proved that the surface destruction, creating rapid crack and consists of many "reflex" zones. These zones occur in areas of origin subsidiaries micro cracks in the vicinity of the crack tip. Location, number and character of these areas depend on the speed of the crack

A Model of Excitation of Deep Crustal Anomalies By a Magnetotelluric Field

We consider a new model of excitation of crustal anomalies that relies on the conjecture of the existence of a weakly conducting layer in the bottom part of the crust. In line with this conjecture, deep fractures may occur in arbitrary positions relative to the conducting anomaly. The model is investigated in the film approximation. We show that magnetotelluric sounding produce a lower biased value for the integral conductivity of the deep anomaly.

Is the Rise of Financial Digital Disruptors Knocking Traditional Banks Off the Track?

The long-term fallout from the 2008 global financial crisis created several deep fractures in traditional-banking models. Most of the sectoral attention today has focused on weak operating profits and balance-sheet performance, especially the risks arising from the negative-rates environment and the collapse in yields on traditional assets, such as highly rated sovereign and corporate debt. Second-tier concerns in boardrooms and amidst C-level executives relate to the continuously evolving regulatory and supervisory pressures and rising associated costs. Finally, the anemic dynamics of the global economic recovery are also seen as a key risk to traditional banks’ profitability. However, from the longer-term perspective, the real risks to the universal banks’ well-established business model come from an entirely distinct direction: the digital-disruption channels that simultaneously put pressure on big banks’ core earnings lines and create ample opportunities for undermining the banking sector’s key unique selling proposition — that is, security of customer funds, data and transactions, and by corollary, enhancing customer loyalty. These channels are FinTech innovations — including rising data intensity of products on offer and technological threats, such as rising risks to cybersecurity. This two-pronged challenge is not unique to the banking sector, but its disruptive potential is a challenge that today’s traditional banking institutions are neither equipped to address nor fully enabled to grasp.

New insights into the formation mechanism of high hydrogen sulfide–bearing gas condensates: Case study of Lower Ordovician dolomite reservoirs in the Tazhong uplift, Tarim Basin

Huge, high gas–oil ratio, hydrogen sulfide (H2S)-bearing gas condensate accumulations were recently discovered in the Ordovician carbonate reservoirs of the Tazhong uplift in the Tarim Basin, northwest China. Distinct differences exist between the eastern and western condensates in terms of chemical and isotopic compositions. Condensates from the western part of the uplift were characterized by high dibenzothiophenes (generally >500 μg/g), a high H2S concentration (∼7%, vol./vol.), and relatively depleted 13C methane (δ13C1 = −55.5‰ to −36‰). The H2S concentration in the Tazhong gas condensates shows a positive correlation to Mg2+ concentration in the formation water. Formation water in Lower Ordovician–Cambrian strata in the Tazhong uplift is rich in Mg2+, which facilitates the thermochemical sulfate reduction (TSR) of sulfate contact ion pairs (CIPs) to produce H2S and dibenzothiophenes. A detailed comparison of the chemical compositions of the formation waters in different strata indicates that a high H2S concentration in the Tazhong gas condensates originates from the TSR of sulfate CIPs in the Lower Ordovician–Cambrian strata, where a primary oil accumulation may have existed. The concentrations of 3- and 4-methyldiamantanes in the western condensates (80 to 150 μg/g) are relatively lower than those from the eastern part of the uplift. Also, the δ13C1 in the western H2S-bearing gas condensates was more negative, and the δ13C2 − δ13C1 value was larger than that from typical TSR-altered gases. These features indicate that the western Tazhong samples had just entered the initial stage of TSR. According to the pressure, volume, temperature (PVT) phase diagram, the lower Paleozoic section was quickly buried after the Tortonian. High-H2S hydrocarbon inclusions formed during the last 10 m.y. when paleotemperatures reached 140°C (284°F). Because the reaction rate of the sulfate CIPs oxidation was relatively slower than that of H2S autocatalysis during the entire TSR process, advanced TSR has not been accomplished yet. It is also inferred that the Tortonian was the key period for accumulation of secondary H2S-bearing gas condensates, resulting from abundant gas washing along deep fractures and charging in the early reservoirs. An increased aromaticity parameter (toluene/n-heptane) and an increased fractionation index from east to west indicate an intensified degree of gas washing. Different gas-washing intensities in the eastern and western gas condensates led to diverse PVT states as well. Deep strata in the Tazhong uplift were characterized by multiple charges and mixing, coupled with periodic TSR, leading to the occurrence of variable H2S-bearing gas condensates.

석회암 분포지에서 터널시공에 따른 지표침하 원인 분석

연구지역은 고생대 지층인 석회암류과 석회암층 사이에 셰일층이 협재하고 이 석회암 상부에 사암 및 탄질셰일층이 분포 한다. 이 퇴적암들의 층리는 서북서 방향의 주향에 북동방향으로 경사지고 있으며 절리들은 경사각이 75도 이상이고 주향은 여러 방향으로 발달한다. 이 지역에는 층리방향과 거의 평행한 파쇄대들은 대규모로 발달하며 이들 파쇄대는 지하 깊이까지 연장되고 있다. 급격한 지하수위의 변화는 5월에 일차 그리고 6월초와 6월 중순에 2차 약 1달 사이 총 3차례의 -4 m에서 시작하여 최대 -15 m까지 하강과 회복을 반복하였으며 이는 지표의 강수량과는 무관함이 확인되었다. 이에 따라 지표침하의 원인은 석회암 내 풍화대와 연결된 터널 심도까지 발달하는 파쇄대와 석회암과 셰일, 석회암과 사암 및 탄질셰일과의 경계부에 발달하는 파쇄대들에서 터널 시공 시 하루에 1000톤 이상의 지하수가 용출되며 지하수위의 급격한 강하와 이에 따라 지하수의 급격한 하강 시 지반에 흡입력을 증가하면서 지표에 침하가 일어난 것으로 해석된다. The aim of this study is the safety and an accident prevention in limestone terrain by the underground tunneling. The geology of the study area consists of a Paleozoic sedimentary sequence dominated by limestone, sandstone, shale, and carbonaceous shale. The sequence gently dips to the northeast but the joint contains steep with variable trend. A significant fracture zone is developed in the limestone and shale beds, sub-parallel to bedding, and follows in part the limestone-sandstone contact. Monitoring of groundwater levels in the area shows marked fluctuations in the water table, which repeatedly rose to a level of -4 m before sinking to -15 m. These cycles occurred in mid-May, 2007 and in early and middle June. The data indicate that these fluctuations were unrelated to rainfall that occurred during the study period. We infer that the fluctuations were associated with the development of underground karstic networks along the deep fracture zone, and overlying ground subsidence is likely related to the rapid sinking of groundwater and the associated strong downward suction force.

Seasonally intermittent water flow through deep fractures in an Alpine Rock Ridge: Gemsstock, Central Swiss Alps

Geological investigations and seismic refraction tomography reveal a series of 70° steep, parallel and continuous fractures at 2950masl within the Gemsstock rock ridge (Central Swiss Alps), at the lower fringe of alpine permafrost. Temperature measurements in a 40m horizontal borehole through the base of the ridge show that whilst conductive heat transfer dominates within the rock mass, brief negative and positive temperature anomalies are registered in summer. These have very small amplitudes and coincide with summer rainfall events lasting longer than 12h. In contrast, a complete lack of anomalous thermal signals during spring snowmelt suggests that runoff does not penetrate the open joints, despite high snow water equivalents of around 400mm. This is attributed to the development of an approximately 20cm thick, continuous and impermeable basal ice layer which forms at the interface between the snow cover and the cold rock on the shady North facing rock wall during snowmelt. Spring snowmelt water therefore does not affect rock temperatures in the centre of the rock mass, despite the presence of deep open joints. The mechanical impact of snowmelt infiltration on rock wall stability at depth is thus assumed to be negligible at this site.

Treatment of acetabular fractures involving the anterior column through the paramedian approach

Objective To explore the surgical techniques and clinical efficacy of the paramedian approach in the treatment of acetabular fractures involving the anterior column. Methods From August 2013 to December 2014, 56 patients with acetabular fracture were treated through the paramedian approach. They were 34 men and 22 women, aged from 29 to 58 years (average, 38 years) . According to Letournel-Judet classification, 12 cases were anterior column fracture, 18 cases fracture of anterior column plus posterior hemitransverse, 9 cases transverse fracture, 6 cases T-shape fracture, and 11 cases both column fracture. All patients were treated by open reduction and internal fixation through the paramedian approach after general anesthesia. After an abdominal midline longitudinal incision was made, the rectus abdominis anterior sheath was cut longitudinally 2-3 cm para-linea alba. After the rectus abdominis was retracted to the lesion side, the rectus abdominis posterior sheath was cut to expose the deep pelvic fracture. In the 12 patients who had been complicated with iliac wing fracture, an additional iliac fossa approach was used. Results The mean surgical time was 105 min (range, from 96 to 188 min) ; the mean blood lose was 400 mL (range, from 200 to 800 mL) ; red cell transfusion was 2.4 units (range, from 0 to 4 units) . The 56 patients were followed up for an average of 16 months (range, from 6 to 22 months) . According to the Matta's fracture reduction assessment, 38 cases were excellent, 11 good, 4 fair, and 3 poor, giving a good-to-excellent rate of 87.5%. All factures healed within 3 months. According to the modified Merle d'Aubigne & Postel scoring at the end of follow-up, the hip joint function was rated as excellent in 34 cases, good in 12, fair in 6 and poor in 4, giving a good-to-excellent rate of 82.1%. No abdominal wall hernias, wound infection or injury to major nerves or vessels was observed during follow-up. Conclusions In the treatment of acetabular fractures involving the anterior column, the paramedian approach can fully reveal anterior wall, anterior column and posterior column of the acetabulum. It is easy to handle and unlikely to injure major vessels and nerves. It also leads to less blood loss. This approach can be used for the majority of acetabular fractures involving the anterior column. Key words: Acetabulum; Fractures, bone; Fracture fixation, internal; Paramedian approach

Yugoslavia in the shadow of war: veterans and the limits of state building, 1903-1945

The Yugoslav state of the interwar period was a child of the Great European War. Its borders were superimposed onto a topography of conflict and killing, for it housed many war veterans who had served or fought in opposing armies (those of the Central Powers and the Entente) during the war. These veterans had been adversaries but after 1918 became fellow subjects of a single state, yet in many cases they carried into peace the divisions of the war years. John Paul Newman tells their story, showing how the South Slav state was unable to escape out of the shadow cast by the First World War. Newman reveals how the deep fracture left by war cut across the fragile states of 'New Europe' in the interwar period, worsening their many political and social problems, and bringing the region into a new conflict at the end of the interwar period.

Active tectonic features and structural dynamics of the summit area of Mt. Etna (Italy) revealed by soil CO2 and soil temperature surveying

This work presents the results of an extensive geochemical survey aimed at measuring soil CO2 effluxes and soil temperatures over a large portion of Mt. Etna's summit area, coupled with an updated structural survey of the same area. The main goals of this study were i) to find concealed or hidden volcano-tectonic structures in the studied area by detecting anomalous soil gas emissions, ii) to investigate the origin of the emitted gas and the mechanism of gas and heat transport to the surface, iii) to produce a structural model based both on the surface geology and on the soil gas data and, lastly, iv) to contribute to the assessment of hazard from slope failure and crater collapses at Mt. Etna. The results revealed many concealed structural lines that followed the major directions of structural weakness in the summit area of Mt. Etna, mostly due to a combined action of gravitational spreading of the volcano and magma intrusions. Both recent and old volcano-tectonic lines were found to act as pathways for the leakage of magmatic gases to the surface. An important role in driving magmatic gases to the surface is also played by fracturing and faulting due to caldera-forming collapses and smaller crater collapses. Correlation between soil CO2 emissions and soil temperature allowed discriminating areas of active shallow hydrothermal circulation along deep fractures (characterized by high values of both parameters, but mostly soil temperature) from those affected by undeveloped fractures that did not reach the surface (characterized by high CO2 emissions at low temperature). The former corresponded to weak zones of the volcano edifice that were frequently site of past eruptions, indicating that those areas keep a high potential for future opening of eruptive fissures. The latter were likely related to sites where new eruptive fissures may open in the near future due to backward propagation of extensional tectonic stress.

José María Arguedas y saber bailar la Historia

El artículo indaga la propuesta narrativa del escritor, antropólogo y musicólogo latinoamericano, José María Arguedas, de ofrecer una historicidad alternativa construida sobre las dinámicas vitales movilizadas por los cuerpos, los saberes y subjetividades que a su vez, constituyen lugar y región en los Andes. A partir del enfoque de las rebeliones indígenas del sur andino del Perú, se analizarán las relaciones entre música, danza y la construcción del sujeto político; su genealogía en la narrativa arguediana y las indagaciones que destacan no sólo las tensiones sino los encuentros posibles que reparan las hondas fracturas e interrupciones históricas.

Flows of Antarctic bottom water through fractures in the southern part of the North Mid-Atlantic Ridge

We study the flows of bottom waters of the Antarctic origin in deep fracture zones of the southern part of the North Mid-Atlantic Ridge. In the autumn of 2014, an expedition onboard the RV Akademik Sergey Vavilov carried out measurements of current velocities and thermohaline properties of bottom water in several quasi-zonal fractures in the southern part of the Northern Mid-Atlantic Ridge, which connect the deep basins of the West and East Atlantic, the Vema Fracture Zone (FZ) (10°50′ N) and a group of sub-equatorial fractures: Doldrums (8°15′ N), Vernadsky (7°40′ N), and a nameless fracture at 7°30′ N. The estimates of bottom water (θ < 2.0°C) transport through this group based on measurements from 2014 are approximately 0.28 Sv (1 Sv = 106 m3/s), which is close to 25% of the transport estimate through the Vema FZ (1.20 Sv) obtained in the same expedition. The coldest bottom water temperatures among the investigated fractures were recorded in the Vema FZ.

Bilateral traumatic pneumothoraces with bilateral deep sulcus signs

Fig. 1. Supine chest radiography shows bilateral deep sulcus signs (arrows) and multiple rib fractures (arrowheads). A 33-year-old man was brought to our emergency department by ambulance after a traffic accident. On arrival, he was drowsy, and dyspnea was noted. He had a respiratory rate of 26 breaths/ min, an oxygen saturation of 88% on a rebreather face mask, a blood pressure of 80/58 mmHg, and a pulse rate of 114 beats/min. The breath sounds over the anterior left side of his chest were decreased, and multiple abrasions were noted over the anterior chest wall. Needle decompression was performed immediately under the impression of tension pneumothorax. A supine chest radiograph revealed both lateral costophrenic angles were abnormally deepened with increased lucency (Fig. 1, arrows) and left rib fractures (Fig. 1, arrowheads). A chest tube was placed on the left side, and the chest computed tomography revealed bilateral pneumothoraces with lung collapse (Fig. 2). A chest tube was placed on the right side, and a repeat chest radiograph revealed decreases in both deepened and hyperlucent lateral costophrenic angles (Fig. 3). After resuscitation, he was transferred to the intensive care unit and discharged home in stable condition 1 month later. Traumatic pneumothorax is an emergency, and is sometimes difficult to identify in critically ill patients. The majority of cases can be diagnosed on an upright posteroanterior chest radiograph [1]. However, only supine chest radiographs are possible in some patients, such as those who have undergone major trauma or are in the intensive care unit. Approximately 30% of pneumothoraces are undetected on supine radiographs because the visceral pleural

A metagenomic window into carbon metabolism at 3 km depth in Precambrian continental crust.

Subsurface microbial communities comprise a significant fraction of the global prokaryotic biomass; however, the carbon metabolisms that support the deep biosphere have been relatively unexplored. In order to determine the predominant carbon metabolisms within a 3-km deep fracture fluid system accessed via the Tau Tona gold mine (Witwatersrand Basin, South Africa), metagenomic and thermodynamic analyses were combined. Within our system of study, the energy-conserving reductive acetyl-CoA (Wood-Ljungdahl) pathway was found to be the most abundant carbon fixation pathway identified in the metagenome. Carbon monoxide dehydrogenase genes that have the potential to participate in (1) both autotrophic and heterotrophic metabolisms through the reversible oxidization of CO and subsequent transfer of electrons for sulfate reduction, (2) direct utilization of H2 and (3) methanogenesis were identified. The most abundant members of the metagenome belonged to Euryarchaeota (22%) and Firmicutes (57%)-by far, the highest relative abundance of Euryarchaeota yet reported from deep fracture fluids in South Africa and one of only five Firmicutes-dominated deep fracture fluids identified in the region. Importantly, by combining the metagenomics data and thermodynamic modeling of this study with previously published isotopic and community composition data from the South African subsurface, we are able to demonstrate that Firmicutes-dominated communities are associated with a particular hydrogeologic environment, specifically the older, more saline and more reducing waters.

Application of gravity and airborne magnetics to structural-magnetic mapping of the metamorphic massive Isla de la Juventud

In an attempt to contribute to the structural mapping of metamorphic massif Isla de la Juventud, with emphasis to acidic magmatism, gravitational-magnetometer data of the territory by means the processing technology Oasis Montaj are used. According to their findings, the presumed postmetamorphic granitic bodies of low density and magnetic susceptibility are located mainly in the central and southwestern part of the massif. On the flanks of Antiform Río Los Indios are mapped rocks of the high part of Cañada Formation, also with low density. The granitic bodies apparently were introduced through the system of longitudinal (synmetamorphic) and transverse (postmetamorphic) faults at the end of the multifolding and metamorphism process of the sequences of the massif, taking a dominant role the zones of longitudinal deep fractures of sublatitudinal direction in the central and southern part of the massif. Late regional dome structure is understand now within the meaning of morfoanticlinal uprising in the region, resulting from the exhumation of metamorphic massif. Does this mean that cracking generated during the evolution of this structure is not affected by acidic magmatism and in consequence for its specific metallogeny of rare and precious metals.

2-D P-wave velocity structure of lithosphere in the North China tectonic zone: Constraints from the Yancheng-Baotou deep seismic profile

We obtained the 2-D P-wave velocity structure of the lithosphere in the eastern North China Craton, Shanxi fault subsidence zone, and Yinchuan-Hetao fault subsidence zone by ray tracking technology based on six groups of clearly identified crustal phases and one group of lithospheric interface reflection phases from seismic recording sections of 21 shots along the 1300-km-long Yancheng-Baotou deep seismic wide-angle reflection/refraction profile. The results indicate significant differences between the lithospheric structure east and west of the Taihang Mountains, which is a gravity-gradient zone as well as a zone of abrupt change in lithospheric thickness and a separation zone of different rock components. East of the Taihang Mountains, the Mesozoic and Cenozoic lithospheric structure of the North China Craton has undergone strong reformation and destruction, resulting in the lithosphere thickness decreasing to 70–80 km. The North China Basin has a very thick Cenozoic sedimentary cover and the deepest point of crystalline basement is about 7.0 km, with the crustal thickness decreasing to about 31.0 km. The crystalline basement of the Luxi uplift zone is relatively shallow with a depth of 1.0–2.0 km and crustal thickness of 33.0–35.0 km. The Subei Basin has a thicker Cenozoic sedimentary cover and the bottom of its crystalline basement is at about 5.0–6.0 km with a crustal thickness of 31.0–32.0 km. The Tanlu fault is a deep fracture which cuts the lithosphere with a significant velocity structure difference on either side of the fault. The Tanlu fault plays an important role in the lithospheric destruction in the eastern part of the North China Craton. West of the Taihang Mountains, the crustal thickness increases significantly. The crust thickness beneath the Shanxi fault depression zone is about 46 km, and there is a low-velocity structure with a velocity of less than 6.1 km s-1 in the upper part of the middle crust. Combined with other geophysical study results, our data shows that the lithospheric destruction at the Shaanxi-Shanxi fault depression zone and the Yinchuan-Hetao rift surrounding the Ordos block is non-uniform. The lithosphere thickness is about 80–90 km in the Datong-Baotou area, 75–137 km at the Dingxiang-Shenmu region, and about 80–120 km in the Anyang-Yichuan area. The non-uniform lithospheric destruction may be related to the ancient tectonic zone surrounding the Ordos block. This zone experienced multi-period tectonic events in the long-term process of its tectonic evolution and was repeatedly transformed and weakened. The weakening level is related to the interactions with the Ordos block. The continental collision between the Cenozoic India and Eurasia plates and N-E thrusting by the Qinghai Tibet Plateau block is causing further reformation and reduction of the lithosphere.

Revealing the unexplored fungal communities in deep groundwater of crystalline bedrock fracture zones in Olkiluoto, Finland.

The diversity and functional role of fungi, one of the ecologically most important groups of eukaryotic microorganisms, remains largely unknown in deep biosphere environments. In this study we investigated fungal communities in packer-isolated bedrock fractures in Olkiluoto, Finland at depths ranging from 296 to 798 m below surface level. DNA- and cDNA-based high-throughput amplicon sequencing analysis of the fungal internal transcribed spacer (ITS) gene markers was used to examine the total fungal diversity and to identify the active members in deep fracture zones at different depths. Results showed that fungi were present in fracture zones at all depths and fungal diversity was higher than expected. Most of the observed fungal sequences belonged to the phylum Ascomycota. Phyla Basidiomycota and Chytridiomycota were only represented as a minor part of the fungal community. Dominating fungal classes in the deep bedrock aquifers were Sordariomycetes, Eurotiomycetes, and Dothideomycetes from the Ascomycota phylum and classes Microbotryomycetes and Tremellomycetes from the Basidiomycota phylum, which are the most frequently detected fungal taxa reported also from deep sea environments. In addition some fungal sequences represented potentially novel fungal species. Active fungi were detected in most of the fracture zones, which proves that fungi are able to maintain cellular activity in these oligotrophic conditions. Possible roles of fungi and their origin in deep bedrock groundwater can only be speculated in the light of current knowledge but some species may be specifically adapted to deep subsurface environment and may play important roles in the utilization and recycling of nutrients and thus sustaining the deep subsurface microbial community.

A Preliminary Review of Metallogenic Regularity of Tin Deposits in China

China is rich in tin resources, and contains many types of tin deposits. Among the tin deposit types, the cassiterite‐sulfide type, skarn type and quartz vein type occupy a large proportion of tin resources and reserves. From the aspect of exploitation and utilization, the most important types are cassiterite‐sulfide type and quartz vein type. The cassiterite‐sulfide type tin deposits are mainly located in Northern Guangxi and Eastern Yunnan, skarn type deposits are mainly distributed in the ore‐concentration areas of South Hunan in Middle Nanling, and the quartz vein type tin deposits are mainly distributed in South China, such as Western Fujian, Middle Jiangxi, Northern Guangzhou and Southern Hunan. The most important metallogenic epoch for tin deposits is the Mesozoic era. The metallogenic geotectonic background is mainly continental environments after orogeny process, with strong tectonic changes, interlaced deep fracture and frequent magmatism. And the most distinctive feature is the well developed Mesozoic granites, which have a close relationship with tin mineralization. Based on the detailed study of the data from 873 tin deposits in China, this paper summarized the metallogenic regularity of tin deposits, classified 20 important metallogenic series of tin or tin‐associated deposits, and inferred that the cassiterite‐sulfide type, skarn type, quartz vein type and greisen type are the main prediction types of tin resources. Forty‐four tin‐mineralization belts were divided, among which, 19 belts are the most important. In addition, a series of maps about tin metallogenic belts and tin metallogenic regularity were compiled, aiming to provide theoretical basis for potential estimation and prediction of tin mineral resources.