Geologia Croatica最新文献

{"title":"Geochronology, geochemistry, and tectonic significance of the Shirenshan gneiss in the southern margin of the North China Block","authors":"Jingya Wang, S. Ren, S. Dong, Longming Li, D. Jiang, Yong-hong Shi, Jiahao Li, Chuanzhong Song, Xu Hang, Zhenqiang Li, J. Ouyang","doi":"10.4154/gc.2019.21","DOIUrl":"https://doi.org/10.4154/gc.2019.21","url":null,"abstract":"The Shirenshan Block is a complex geological body located in the southern margin of the North China Block (NCB). From south to north, it can be divided into the Taihua Group migmatite, and the Shirenshan gneiss and magmatic rocks. The petrographic features, tectonic setting, provenance, and geological age of the Shirenshan gneiss using comprehensive field investigations, microstructural analysis, zircon U-Pb radioactive dating, and geochemical analyses were investigated for this study. The petrology, geochemistry, and geochronology of the Shirenshan gneiss suggests that it is mainly a felsic rock and its protolith was a high-K calc-alkaline series A-type granite. The protolith is high in SiO2, Al2O3, K2O, Na2O, and low in CaO and MgO. Overall, the Sr-Nd isotope composition of the samples showed no significant difference, indicating that the Taihua Group migmatite and the Shirenshan gneiss have the same source material. The Shirenshan block may be partially melted from the Taihua group and formed during activity of the Luo-Luan Fault. By the method of zircon dating analysis, the protolith age of the Shirenshan block was determined as 1559±16Ma (Early Proterozoic). Then, the crystallization age of the syntectonic migmatite is 439.2±7.6Ma, which was formed by subduction of the Taihua Group. During the early Cretaceous (119.5±1.3Ma), the Shirenshan gneiss may have experienced regional migmatization and formed the zircon rims age of the Yanshanian period. Litho-geochemical features of the Shirenshan block are similar to A1-type granites indicating that they are post-orogenic. Therefore, the metamorphic deformation of the Shirenshan gneiss reflects the tectonics in the southern margin of the NCB.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"33-45"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49511342","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Integrated 3D modeling of Quaternary sediments in the Beijing Plain, based on a sequential indicator simulation","authors":"Xiaoyan Ai, B. Sun, Xiangzhao Chen","doi":"10.4154/gc.2019.28","DOIUrl":"https://doi.org/10.4154/gc.2019.28","url":null,"abstract":"The study of Quaternary sediments has long been a focus for geologists, primarily because they are closely aligned with urban safety assessment, energy exploitation and sustainable development. The Beijing Plain was selected for this study. Using existing drilling data and knowledge of the sedimentary characteristics in this study area, a geological model was developed with Petrel software using the sequential indicator simulation algorithm. The main aims were firstly, to integrate ArcGIS and Petrel with drilling information, a digital elevation model, a stratum sedimentary thickness plan and other multi-platform data on the same platform. Secondly, establish a lithology variogram model and then construct a quaternary lithology model based on the variogram model and finally, use the established lithology model to preliminarily analyze the lateral and vertical distribution rules of Quaternary lithology in the study area. These results provide new methods for the establishment of geologic modeling during the preliminary stages when studying engineering geology. The results will also provide baseline information for later research.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"3-17"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70281179","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ore-forming fluids of the Fancha gold deposit, Lingbao, Henan Province","authors":"Zhang-fa Yu, Ca Yi, Li Hongmeng","doi":"10.4154/gc.2019.22","DOIUrl":"https://doi.org/10.4154/gc.2019.22","url":null,"abstract":"The Fancha gold deposit is a representative of the auriferous quartz vein type gold deposits in the Xiaoqingling gold district where the ore-forming fluid is one of the key controlling factors in the deposits formation, and also the main focus of ore deposit research. Here, the geological characteristics and fluid inclusions of the Fancha deposit are presented in detail, with a description of the potential origin and evolution of the fluid and the genesis of the deposit. Field investigation and petrographic observation show that ore-bodies in the Fancha deposit are preferentially hosted in the amphibolites of the Taihua Group and are controlled by brittle fracture. Hydrothermal alteration in the Fancha deposit includes silicification, potash feldspathization, sericitization, pyritization and carbonatization. The mineral assemblage, cross-cutting and replacement relationships indicate that the ore-forming process can be divided into quartz-K-feldspar (I), quartz-coarse pyrite (Ⅱ), quartz-fine pyrite (III), quartz-polymetallic sulfide (IV) and carbonate stages (V). Gold is mainly precipitated in stages III and IV. Three types of fluid inclusions have been identified in the Fancha deposit, based on their characteristics at room temperature: three-phase CO2-rich, three-phase CO2-bearing and two-phase aqueous inclusions. The fluid inclusions demonstrate the modes of homogenization temperatures of 363.3℃, 325.5℃, 273℃, 258.62℃ and salinities of 14.53, 9.59, 11.61, 8.03 wt% NaCl.equiv., for stages II, III, IV, and V respectively. The ore-forming fluid in the Fancha deposit belonged to the CO2-H2O-NaCl-(±CH4) fluid system with mid-low temperature and mid-low salinity. The δ18OH2O of the metallogenic fluids was between 1.36 and 6.28, and the δDH2O was between -87 and -53.1. Hydrogen and oxygen isotope data indicate that the ore-forming fluids were dominated by metamorphic fluids in the early stage, and that the metamorphic fluid gradually mixed with circulating meteoric water during the later stages. Petrographic observation and microthermometry suggest that fluid mixing and immiscibility obviously occurred during the main metallogenic stage. Fluid mixing and fluid immiscibility probably led to gold deposition in the Fancha deposit.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"127-143"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47337253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A new numerical method for the analysis of monolithic seepage problems with complex drainage systems in a groundwater recharge area for a hydropower station in China","authors":"Y. Jun, Liu Si-hong, Wei Ying-qi, Jin Song-Li, Cai Hong, Xiao Jian-zhang","doi":"10.4154/gc.2019.24","DOIUrl":"https://doi.org/10.4154/gc.2019.24","url":null,"abstract":"After construction of a dam impounding water in a reservoir, a monolithic seepage field develops in the surrounding rock mass. Here, a new finite element method is proposed for determining the shape and characteristics of the 3D monolithic seepage field including the free surface, considering complex drainage systems consisting of densely-spaced drainage holes and drainage galleries. To this end, the previously proposed virtual flux method is improved by a refined numerical integration scheme and a regularized Heaviside function for distinguishing the subregions below and above the free surface within a particular finite element. Leakage and overflow drainage holes are modeled as internal boundaries. The proposed numerical method is verified by an academic example, for which the analytical solution is available. Finally, the numerical simulation of the seepage field developing in the vicinity of a high dam and underground power house, constructed in the context of a hydropower plant project in China is used to show its application to a problem in engineering practice.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"47-56"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44597898","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Meso/Micro-texture analysis of the landslide-dam outburst sediments in the Upper Jinsha River, SE Tibetan Plateau","authors":"Jian Chen, Z. Cui, Chaohui Liu, Wendy Zhou, Ruichen Chen","doi":"10.4154/gc.2019.29","DOIUrl":"https://doi.org/10.4154/gc.2019.29","url":null,"abstract":"Outburst sediments are widely distributed in the Upper Jinsha River in the Southeastern (SE) Tibetan Plateau. In order to understand the sedimentary characteristics of these sediments, gravel fabric, particle size distribution and quartz sand surface textures were used to analyze the mesotextures and microtextures of the Xuelongnang outburst sediments. It was determined that these sediments usually have a short transport distance, and are distributed over a distance of approximately 3.5 km. The gravel fabric and particle size distribution analysis represent the different mesotextures with different transport distances and suggest gradually changing hydrodynamic conditions. The statistical data of quartz surface textures exhibit the transformation process of quartz sands by outburst flood. The variation from abundant sub-angular shapes (> 75%); to common V-shaped percussion cracks, solution crevasse, medium relief, and chatter marks (50% to 75%); to rare meandering ridge, underwater polished surface, large conchoidal fracture (> 100 μm), directional etch pits, and crystalline overgrowths (< 5%), present the features in different combinations to other sedimentary environments. The microtexture characteristics of landslide-dam outburst deposits are also consistent with those of the mesotextures. As the distance from the residual dam increased, the quartz grain microtextures showed gradual or abrupt changes, such as increased frequencies of V-shaped percussion cracks, decreased frequencies of the adhering particles, and growth of the solution crevasses. These findings could potentially be used as a discriminant mark to distinguish outburst sediment from other types of sediments, e.g., subaqueous, eolian, glacial, etc.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"81-91"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41616292","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Dispersed plant mesofossils from the Permian of Wuda, Inner Mongolia, Taiyuan Formation, China","authors":"Z. Šimůnek, J. Bureš","doi":"10.4154/gc.2019.17","DOIUrl":"https://doi.org/10.4154/gc.2019.17","url":null,"abstract":"A coal sample from the Lower Permian Taiyuan Formation (Wuda locality, Inner Mongolia, China) was macerated. It yielded two cuticle fragments and many fragments of conducting tissue. One cuticle fragment shows strongly corroded polygonal cells belonging either to a pteridosperm or a cycad. The second fragment is an abaxial cordaitalean cuticle with papillate tetragonal cells and can be compared to Cordaites neimengensis LIU et al. 1998. The conducting tissue are represented by biseriate to quadriseriate tracheid pitting that is typical for cordaitaleans.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4154/gc.2019.17","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44764247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Chemical, mineralogical and structural features of native and expanded perlite from Macedonia","authors":"Arianit A. Reka, B. Pavlovski, K. Lisichkov, Ahmed Jashari, B. Boev, I. Boev, M. Lazarova, V. Eskizeybek, A. Oral, G. Jovanovski, P. Makreski","doi":"10.4154/gc.2019.18","DOIUrl":"https://doi.org/10.4154/gc.2019.18","url":null,"abstract":"The physico-mechanical, chemical and mineralogical characteristics of volcanic glass (perlite) from the Mariovo region (Macedonia) as well as the mineralogical changes that occur during its thermal treatment were investigated to demonstrate its utilization for industrial use. The native perlite was characterized by chemical analysis, X-ray powder diffraction (XRPD), infrared (IR) spectroscopy, thermal analysis (TGA/DTA), scanning electron microscopy (SEM-EDX), transmission electron microscopy (TEM), and solid- state NMR. The chemical examination suggests that the perlite represents an acidic volcanic rock with a high percentage of SiO2 (72.45%), high in alkali metal oxides (4.21 wt.% K2O, 3.56 wt.% Na2O), with a loss of ignition 3.54 wt.%. Results from the XRPD indicated major amorphous behaviour, with low amounts of feldspars, quartz, and cristobalite. SEM examinations revealed glassy structure with presence of certain pores (dimensions ranging from 50–100 μm). The determined expansion coefficient was 20 times its original volume. XRPD of expanded perlite compared to the native perlite depicted new intensive peaks of cristobalite. SEM and TEM revealed irregular morphology with broken or ragged edges. On the basis of the chemical and mineralogical composition, the studied perlite is classified as an appropriate material suitable as ceramic flux to lower the sintering temperature.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4154/gc.2019.18","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45297760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Northern Velebit (Croatia) karst hydrological system: results of a preliminary 2H and 18O stable isotope study","authors":"D. Paar, D. Mance, A. Stroj, M. Pavić","doi":"10.4154/GC.2019.15","DOIUrl":"https://doi.org/10.4154/GC.2019.15","url":null,"abstract":"Researching the hydrogeological properties of karst systems is very challenging due to their ex- treme heterogeneity. A grey-box approach in karst res","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48592018","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Revision of the genus Cordaites UNGER from the Permian of the Intrasudetic Basin (Broumov Formation, Olivětín Member, Czech Republic)","authors":"Z. Šimůnek","doi":"10.4154/gc.2019.16","DOIUrl":"https://doi.org/10.4154/gc.2019.16","url":null,"abstract":"Cordaitalean remains are not very common in the Permian of the Intrasudetic Basin (Czech Republic and Poland) and have usually been classified simply as Cordaites sp. Based on leaf morphology, venation and cuticles (where possible), five cordaitalean species are recognised: Cordaites cf. beinertianus, C. cf. affinis, C. cf. roesslerianus, C. cf. foliolatus and Cordaites sp. A. The determination of Cordaites leaves is difficult because of the variability and similarities between several species. The biggest leaf was determined as Cordaites cf. beinertianus. The cuticles of Cordaites cf. affinis resemble the cuticles of C. palmaeformis and C. radvanicensis,however, the latter is known only in a fragmentary state. Cordaites beinertianus and C. palmaeformis are very similar and are considered as conspecific by some authors. Cordaites affinis has generally smaller leaves. Cordaites cf. roesslerianus is comparable with C. principalis with which it is sometimes synonymised. C. cf. foliolatus is represented by a much narrower leaf than is typical for cordaitalean leaves from France. Cordaites sp. A is a relatively small leaf-form and differs from all other forms previously described.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46222520","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the origin of both a recent and submerged tombolo on Prvić Island in the Kvarner area (Adriatic Sea, Croatia)","authors":"Č. Benac, N. Bočić, I. Ružić","doi":"10.4154/gc.2019.14","DOIUrl":"https://doi.org/10.4154/gc.2019.14","url":null,"abstract":"This paper analyzes the origins of two tombolos (one recent and another fossil/submerged) on the southwestern coast of Prvic Island, which is located in the Kvarner area in the northeastern part of the Adriatic Sea. \u0000A recent tombolo on Cape Pipa was formed by the erosion of Quaternary deposits and Palaeogene siliciclastic rocks. The submerged tombolo is much bigger, clearly visible on the sea bed toward the southwest. The conditions for forming a submerged and recent tombolo have occurred during a slow rise and then stagnation of sea level of the Adriatic Sea in the Holocene. The sea  flooded the fossil tombolo probably in the final part of a period of rapid sea-level rise at the beginning of the Holocene when a large proportion of the Quaternary sediments were eroded. Waves from the northwest (tramuntana) and southeast (jugo) refract and diffract around the tombolo. The nourishment of the beach body happens permanently on both sides of the cape. Accumulated sediments are protected by resistant rocky blocks of breccia on the peak of Cape Pipa, acting as a natural tombolo. Due to the fact that wave directions are perpendicular to the beach coastline, they do not generate longshore currents that would erode sediment in beach bodies around Cape Pipa. Therefore, the recent tombolo is probably stable in the present climatic and oceanographic conditions in the Kvarner area.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":" ","pages":""},"PeriodicalIF":1.3,"publicationDate":"2019-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44753082","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}