The main purpose of this contribution is to develop realistic prediction digital soil maps in order to increase their visuality, and to evaluate and compare the performance of different modeling techniques: a) Kriging, b) Artificial Neural Network – Multilayer Perceptron (ANN-MLP) and c) Multiple Polynomial Regressions (MPR). The following criteria were used to determine selection of the testing site for the modeling: (1) intensive metal ore mining and metallurgical processing; (2) geomorphological natural features; (3) regular geological setting, and (4) the remaining minefields. The success of Digital Soil Mapping and the plausibility of prediction maps increases with the availability of spatial data, the availability of computing power for processing data, the development of data-mining tools, geographical information systems (GIS) and numerous applications beyond geostatistics. Advanced prediction modeling techniques, ANN-MLP and MPR include geospatial parameters sourced from Digital Elevation Models (DEM), land use and remote sensing, applied in combination with costly and time-consuming soil measurements, developed and finally incorporated into the models of spatial distribution in the form of 2D or 3D maps. Innovative approaches to modeling assist us in the reconstruction of different processes that impact the entire study area, simultaneously. This holistic approach represents a novelty in contamination mapping and develops prediction models to help in the reconstruction of main distribution pathways, to assess the real size of the affected area as well as improving the data interpretation.
{"title":"Application and improvement of soil spatial distribution mapping using advanced modelling techniques","authors":"Jasminka Alijagić, R. Šajn","doi":"10.4154/gc.2020.01","DOIUrl":"https://doi.org/10.4154/gc.2020.01","url":null,"abstract":"The main purpose of this contribution is to develop realistic prediction digital soil maps in order to increase their visuality, and to evaluate and compare the performance of different modeling techniques: a) Kriging, b) Artificial Neural Network – Multilayer Perceptron (ANN-MLP) and c) Multiple Polynomial Regressions (MPR). The following criteria were used to determine selection of the testing site for the modeling: (1) intensive metal ore mining and metallurgical processing; (2) geomorphological natural features; (3) regular geological setting, and (4) the remaining minefields. \u0000The success of Digital Soil Mapping and the plausibility of prediction maps increases with the availability of spatial data, the availability of computing power for processing data, the development of data-mining tools, geographical information systems (GIS) and numerous applications beyond geostatistics. Advanced prediction modeling techniques, ANN-MLP and MPR include geospatial parameters sourced from Digital Elevation Models (DEM), land use and remote sensing, applied in combination with costly and time-consuming soil measurements, developed and finally incorporated into the models of spatial distribution in the form of 2D or 3D maps. Innovative approaches to modeling assist us in the reconstruction of different processes that impact the entire study area, simultaneously. This holistic approach represents a novelty in contamination mapping and develops prediction models to help in the reconstruction of main distribution pathways, to assess the real size of the affected area as well as improving the data interpretation.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"73 1","pages":"69-84"},"PeriodicalIF":1.3,"publicationDate":"2020-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42685868","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}
Zvonka Gverić, D. Hanzel, Š. Kampić, A. Pleša, D. Tibljaš
Bentonites are an important industrial resource and are also interesting from the mineralogical point of view. The main component of bentonites is a mineral from the smectite group in which chemical and structural variations, influencing bentonite properties, provide a great deal of interesting research topics. The aim of this study was to better describe bentonites from 11 known deposits from Croatia and neighbouring countries: Bednja, Bunaric, Draga, Divoselo, Sjenicak, Paripovac, Loncarski Vis and Poljanska Luka (Croatia), Zaloska Gorica (Slovenia), Sipovo (Bosnia and Herzegovina) and Vranjska Banja (Serbia). Thirteen samples were analysed using several available techniques in order to obtain the data necessary for currently accepted bentonite classification. The mineralogical composition was analysed using XRD and FTIR, and crystallo-chemical properties were investigated by thermal analysis, CEC determination with ammonium index cations, chemical analyses (ICP-AES and ICP-MS) and Mossbauer spectroscopy. The results showed that the main mineral constituent of most local bentonite deposits is a Fe-poor smectite, with a predominantly medium layer charge mostly as a result of octahedral substitutions, with calcium or sodium cations occupying the interlayer. Nevertheless, the variations between samples are prominent enough to provide a good overview of the range of crystallo-chemical properties which exist in different smectites resulting in varying bentonite properties.
{"title":"Comprehensive characterization of bentonites from Croatia and neighboring countries","authors":"Zvonka Gverić, D. Hanzel, Š. Kampić, A. Pleša, D. Tibljaš","doi":"10.4154/gc.2020.02","DOIUrl":"https://doi.org/10.4154/gc.2020.02","url":null,"abstract":"Bentonites are an important industrial resource and are also interesting from the mineralogical point of view. The main component of bentonites is a mineral from the smectite group in which chemical and structural variations, influencing bentonite properties, provide a great deal of interesting research topics. The aim of this study was to better describe bentonites from 11 known deposits from Croatia and neighbouring countries: Bednja, Bunaric, Draga, Divoselo, Sjenicak, Paripovac, Loncarski Vis and Poljanska Luka (Croatia), Zaloska Gorica (Slovenia), Sipovo (Bosnia and Herzegovina) and Vranjska Banja (Serbia). Thirteen samples were analysed using several available techniques in order to obtain the data necessary for currently accepted bentonite classification. The mineralogical composition was analysed using XRD and FTIR, and crystallo-chemical properties were investigated by thermal analysis, CEC determination with ammonium index cations, chemical analyses (ICP-AES and ICP-MS) and Mossbauer spectroscopy. The results showed that the main mineral constituent of most local bentonite deposits is a Fe-poor smectite, with a predominantly medium layer charge mostly as a result of octahedral substitutions, with calcium or sodium cations occupying the interlayer. Nevertheless, the variations between samples are prominent enough to provide a good overview of the range of crystallo-chemical properties which exist in different smectites resulting in varying bentonite properties.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"73 1","pages":"29-48"},"PeriodicalIF":1.3,"publicationDate":"2020-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47277605","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}
Petra Jagodnik, V. Jagodnik, Ž. Arbanas, S. M. Arbanas
The Slani Potok gully (0.48 km2) is situated in the central part of the Vinodol Valley (64.57 km2) in Croatia, and it was formed in the Eocene flysch deposits. So far, the area of Slani Potok has been mainly referred in the scientific literature as being subjected to unusually intense soil erosion processes (i.e., ‘’excessive erosion’’), associated with landslides. However, the landslides were never investigated in detail, given the available research methods only involved field investigations. Therefore, the landslide types according to the most commonly used landslide classifications have remained undetermined. In this paper, landslide types in the Slani Potok gully are presented, identified and mapped based on the visual interpretation of seven different LiDAR topographic derivatives computed from the 1 x 1 m DTM available from March 2012. The geomorphological historical landslide inventory of the Slani Potok gully was created, consisting of 181 landslide phenomena. Landslides cover 69 % of the area (0.33 km2) of the Slani Potok gully. The size of the smallest landslide is 65 m2, and of the largest is 10,563 m2. Landslides are very small to moderate-small, shallow to moderate-shallow, and mainly successive in distribution. Most of the landslides initiate along the margins of the gully channel walls, and extend to the gully channel bottom. Such a large number of identified landslides, as well as their specific spatial arrangement within the gully, indicates that sliding processes predominantly affect the morphologic development of the Slani Potok gully, and that the soil erosion is the secondary process in the study area.
Slani Potok沟(0.48 km2)位于克罗地亚Vinodol山谷(64.57 km2)的中部，形成于始新世的复理石质沉积中。到目前为止，斯拉尼波托克地区在科学文献中主要被提到遭受与滑坡有关的异常强烈的土壤侵蚀过程(即“过度侵蚀”)。然而，由于现有的研究方法只涉及实地调查，因此从未对滑坡进行详细调查。因此，根据最常用的滑坡分类，滑坡类型仍未确定。本文基于2012年3月1 x 1 m DTM计算的7种不同激光雷达地形导数的视觉解释，介绍、识别和绘制了Slani Potok沟的滑坡类型。建立了斯拉尼波托克沟滑坡地貌历史清查表，收录了181个滑坡现象。滑坡覆盖了斯拉尼波托克沟69%的面积(0.33平方公里)。最小的滑坡面积为65平方米，最大的滑坡面积为10563平方米。滑坡的分布类型为极小到中小，浅到中浅，以连续分布为主。滑坡多发生在沟道壁边缘，并向沟道底部延伸。如此多的已识别滑坡及其在沟内的具体空间分布表明，滑动过程主要影响斯拉尼波托克沟的形态发育，土壤侵蚀是研究区内的次要过程。
{"title":"Landslide types in the Slani Potok gully, Croatia","authors":"Petra Jagodnik, V. Jagodnik, Ž. Arbanas, S. M. Arbanas","doi":"10.4154/gc.2020.04","DOIUrl":"https://doi.org/10.4154/gc.2020.04","url":null,"abstract":"The Slani Potok gully (0.48 km2) is situated in the central part of the Vinodol Valley (64.57 km2) in Croatia, and it was formed in the Eocene flysch deposits. So far, the area of Slani Potok has been mainly referred in the scientific literature as being subjected to unusually intense soil erosion processes (i.e., ‘’excessive erosion’’), associated with landslides. However, the landslides were never investigated in detail, given the available research methods only involved field investigations. Therefore, the landslide types according to the most commonly used landslide classifications have remained undetermined. In this paper, landslide types in the Slani Potok gully are presented, identified and mapped based on the visual interpretation of seven different LiDAR topographic derivatives computed from the 1 x 1 m DTM available from March 2012. The geomorphological historical landslide inventory of the Slani Potok gully was created, consisting of 181 landslide phenomena. Landslides cover 69 % of the area (0.33 km2) of the Slani Potok gully. The size of the smallest landslide is 65 m2, and of the largest is 10,563 m2. Landslides are very small to moderate-small, shallow to moderate-shallow, and mainly successive in distribution. Most of the landslides initiate along the margins of the gully channel walls, and extend to the gully channel bottom. Such a large number of identified landslides, as well as their specific spatial arrangement within the gully, indicates that sliding processes predominantly affect the morphologic development of the Slani Potok gully, and that the soil erosion is the secondary process in the study area.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"73 1","pages":"13-28"},"PeriodicalIF":1.3,"publicationDate":"2020-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4154/gc.2020.04","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46126813","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}
Zhou Zhang, M. Zhoua, Yunxing Cao, Baoan Xian, Di Gao
The structural fracture system in a coal reservoir enables coalbed methane (CBM) percolation and migration. It plays an important role in CBM exploration and exploitation (recovery) development. Nearly vertical strata with Mesozoic bituminous coal seams in the central part of the Kuba coalfield of the Xinjiang Province in China were studied using large-scale mapping of the structural fractures on the surface, and a using a technique for comparing and analyzing sections of the underground coal mine. This investigation verified that similar structural fractures are developed in the underground coal seams as those on the surface, , and surrounding rocks represent the same tectonic layer. Meanwhile, a corresponding relationship between the characteristics of the development of fractures - including the growth directions and degree of development of fractures in coal seams and the surrounding rocks - was established. Based on this, the research presents a new method for predicting a pattern of fractures in coal seams and the coal structure, respectively. Finally, the study area was divided into zones with dense, moderate and un-developed fractures. The method should be applicable in various coal-and-gas engineering fields, for example the prediction of fractured zones in coal seams, the prediction of coal structure, and for projecting the well arrangement in the exploration and development of economic recovery of CBM.
{"title":"The prediction of structural fractures in coal seams of the Kuba coalfield, China: an application for coalbed methane (CBM) recovery development","authors":"Zhou Zhang, M. Zhoua, Yunxing Cao, Baoan Xian, Di Gao","doi":"10.4154/gc.2019.26","DOIUrl":"https://doi.org/10.4154/gc.2019.26","url":null,"abstract":"The structural fracture system in a coal reservoir enables coalbed methane (CBM) percolation and migration. It plays an important role in CBM exploration and exploitation (recovery) development. Nearly vertical strata with Mesozoic bituminous coal seams in the central part of the Kuba coalfield of the Xinjiang Province in China were studied using large-scale mapping of the structural fractures on the surface, and a using a technique for comparing and analyzing sections of the underground coal mine. This investigation verified that similar structural fractures are developed in the underground coal seams as those on the surface, , and surrounding rocks represent the same tectonic layer. Meanwhile, a corresponding relationship between the characteristics of the development of fractures - including the growth directions and degree of development of fractures in coal seams and the surrounding rocks - was established. Based on this, the research presents a new method for predicting a pattern of fractures in coal seams and the coal structure, respectively. Finally, the study area was divided into zones with dense, moderate and un-developed fractures. The method should be applicable in various coal-and-gas engineering fields, for example the prediction of fractured zones in coal seams, the prediction of coal structure, and for projecting the well arrangement in the exploration and development of economic recovery of CBM.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"57-69"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41800499","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":"Editorial: 6th International Conference on Geology Resources Management and Sustainable Development (ICGRMSD2018)","authors":"Guangli Xu, L. Galović","doi":"10.4154/gc.2019.30","DOIUrl":"https://doi.org/10.4154/gc.2019.30","url":null,"abstract":"","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"1-1"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48137632","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}
Yu Xiaobo, Fang Nian-qiao, Zhang Zhenguo, D. Hailong
During the early Mesozoic Era there was intense magmatic activity near Hainan Island, South China. As a result, the granites of Hainan Island provide information on, and are suitable material to potentially improve understanding of the Cretaceous tectonic environment of the northern margin of the South China Sea. The Gaofeng and Baocheng intrusions are composed mainly of medium- to fine-grained biotite adamellite (Baocheng) and granodiorite (Gaofeng). The two intrusions yielded U–Pb LA-ICP-MS zircon ages of 107.7 ± 6.1 Ma (Gaofeng) and 105.8 ± 2.4 Ma (Baocheng). Regarding the major elements, the Gaofeng and Baocheng intrusions had medium Si and alkali contents and high Ca, Mg, and Al contents, with an aluminum saturation index of 0.95–1.03 and 1.05–1.30. The trace element and rare earth element (REE) characteristics showed that the two intrusions have intense heavy REE/light REE (HREE/LREE) fractionation, LREE enrichment, HREE depletion, and weak negative Eu anomalies. The intrusions were enriched in high field-strength elements and depleted in large ion lithophile elements. These geochemical characteristics indicate that the Hainan Province was in a tectonic subduction environment in the late Yanshanian period. Multiple geochemical characteristics demonstrate that the granites in the Hainan Province were formed by a different mechanism and in a different setting from those in Fujian and Zhejiang. The late Mesozoic granites of Fujian and Zhejiang were formed by the Western Pacific subduction. However, Hainan Island was under an arc environment formed by the northward subduction of the Tethyan-South China Sea during the Cretaceous leading to emplacement of the Gaofeng and Baocheng intrusions.
{"title":"The characteristics of granites in the Gaofeng and Baocheng areas, Hainan Province, China: response to subduction of the Tethyan South China Sea","authors":"Yu Xiaobo, Fang Nian-qiao, Zhang Zhenguo, D. Hailong","doi":"10.4154/gc.2019.19","DOIUrl":"https://doi.org/10.4154/gc.2019.19","url":null,"abstract":"During the early Mesozoic Era there was intense magmatic activity near Hainan Island, South China. As a result, the granites of Hainan Island provide information on, and are suitable material to potentially improve understanding of the Cretaceous tectonic environment of the northern margin of the South China Sea. The Gaofeng and Baocheng intrusions are composed mainly of medium- to fine-grained biotite adamellite (Baocheng) and granodiorite (Gaofeng). The two intrusions yielded U–Pb LA-ICP-MS zircon ages of 107.7 ± 6.1 Ma (Gaofeng) and 105.8 ± 2.4 Ma (Baocheng). Regarding the major elements, the Gaofeng and Baocheng intrusions had medium Si and alkali contents and high Ca, Mg, and Al contents, with an aluminum saturation index of 0.95–1.03 and 1.05–1.30. The trace element and rare earth element (REE) characteristics showed that the two intrusions have intense heavy REE/light REE (HREE/LREE) fractionation, LREE enrichment, HREE depletion, and weak negative Eu anomalies. The intrusions were enriched in high field-strength elements and depleted in large ion lithophile elements. These geochemical characteristics indicate that the Hainan Province was in a tectonic subduction environment in the late Yanshanian period. Multiple geochemical characteristics demonstrate that the granites in the Hainan Province were formed by a different mechanism and in a different setting from those in Fujian and Zhejiang. The late Mesozoic granites of Fujian and Zhejiang were formed by the Western Pacific subduction. However, Hainan Island was under an arc environment formed by the northward subduction of the Tethyan-South China Sea during the Cretaceous leading to emplacement of the Gaofeng and Baocheng intrusions.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"93-109"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44067877","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}
A multi-point geostatistical method for ore grade estimation is introduced in order to fully utilize existing sampling information. A block model is used to construct a new three-dimensional training image instead of a variogram. Data events and pattern matching is improved, and the directionality of the data template is considered in the matching. The inverse distance weighted method is used to make up for the lack of multi-point geostatistics. The research improves the reliability of multi-point geostatistical estimation. Optimal estimation results for Li2O and Ta2O5 come from the inverse distance weighted, ordinary Kriging, and multi-point geostatistical methods. Multi-point geostatistical estimation results are compared with those of the inverse distance weighted and ordinary Kriging methods. Deviation, trend, and variogram analyses are used to assess the effect of multipoint geostatistical estimation. This study shows that reducing the samples participating in the estimation can reduce the maximum and minimum deviation of the estimated grade to a certain extent. The grade distribution pattern is the primary factor affecting minimum and maximum deviation. This study proves the reliability and accuracy of the multi-point geostatistical method for ore grade estimation.
{"title":"Multi-point geostatistics for ore grade estimation","authors":"Yu-Chen Song, Zhan-Ning Liu, Hai-Dong Meng, Xiao-Yan Yu","doi":"10.4154/gc.2019.23","DOIUrl":"https://doi.org/10.4154/gc.2019.23","url":null,"abstract":"A multi-point geostatistical method for ore grade estimation is introduced in order to fully utilize existing sampling information. A block model is used to construct a new three-dimensional training image instead of a variogram. Data events and pattern matching is improved, and the directionality of the data template is considered in the matching. The inverse distance weighted method is used to make up for the lack of multi-point geostatistics. The research improves the reliability of multi-point geostatistical estimation. Optimal estimation results for Li2O and Ta2O5 come from the inverse distance weighted, ordinary Kriging, and multi-point geostatistical methods. Multi-point geostatistical estimation results are compared with those of the inverse distance weighted and ordinary Kriging methods. Deviation, trend, and variogram analyses are used to assess the effect of multipoint geostatistical estimation. This study shows that reducing the samples participating in the estimation can reduce the maximum and minimum deviation of the estimated grade to a certain extent. The grade distribution pattern is the primary factor affecting minimum and maximum deviation. This study proves the reliability and accuracy of the multi-point geostatistical method for ore grade estimation.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"111-126"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44187233","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}
The main objective of this study was to quantify the dynamics of ammonium (NH4+) and nitrate (NO3-) in the humus (0-7cm) and the uppermost mineral layer (0-15cm) of a forest soil. The soil was treated annually from 2012 to 2013 with one single dose of nitrogen (0, 15, 30kg N ha-1yr-1 applied as (NH4)2SO4, NH4Cl, KNO3). Net N mineralization, including net ammonification and net nitrification was determined in four in situ incubation periods over 2 years in a Picea-Abies forest stand at the Qinghai-Tibet Plateau, Southwest China. Measurements were done using soil cores (7cm or 15cm deep) with a resin bag filled with combined anion and cation exchange resins placed at the base to collect the N leaching from the soil. The accumulation rate of N was corrected for both deposition and fertilizer N inputs. In all treatments, both the content and accumulation of the mineral N were dominated by NH4+ which accounts for about 76-89% of the net mineralization. The accumulation rate of N decreased to 64-83% in KNO3 treatments. The net N mineralization rate increased with nitrogen input, especially in NH4+-N treatments (p<0.05). However, this promoting role decreased over time. At the highest (NH4)2SO4 additions, the net ammonification and net mineralization rate increased notably in the humus (0-7cm) rather than in the uppermost mineral layer (0-15 cm). Previous studies that reported on soil net mineralization from forests under different environmental conditions were compiled and assessed for the effects of atmospheric N deposition and environmental factors, annual precipitation, and annual temperature on annual fluxes of net nitrogen mineralization in forest soils, worldwide. The results show that an increase in atmospheric N deposition significantly enhances the soil net nitrogen mineralization rate. Variation in atmospheric N deposition accounts for 48% of the variation in the rate of soil net nitrogen mineralization across the forests.
本研究的主要目的是量化森林土壤腐殖质（0-7cm）和最上层矿物层（0-15cm）中铵（NH4+）和硝酸盐（NO3-）的动态。从2012年到2013年，每年对土壤进行一次单剂量的氮处理（0，15，30kg N ha-1yr-1，以（NH4）2SO4、NH4Cl和KNO3的形式施用）。在青藏高原云杉林中，通过4个2年的原位培养期测定了净氮矿化，包括净氨化和净硝化作用。使用土壤芯（7厘米或15厘米深）进行测量，并在底部放置一个装有阴离子和阳离子交换树脂的树脂袋，以收集土壤中的N浸出物。对沉积和肥料氮输入的氮积累率进行了校正。在所有处理中，矿物N的含量和积累都以NH4+为主，NH4+约占净矿化的76-89%。KNO3处理的氮素积累率降至64-83%。净氮矿化率随着施氮量的增加而增加，尤其是在NH4+-N处理中（p<0.05），但这种促进作用随着时间的推移而减弱。在（NH4）2SO4添加量最高的情况下，腐殖质（0-7cm）的净氨化率和净矿化率显著增加，而不是最上层（0-15cm）。以往关于不同环境条件下森林土壤净矿化的研究都是针对大气氮沉积和环境因素、年降水量和年温度对全球森林土壤净氮矿化年通量的影响进行汇编和评估的。结果表明，大气氮沉降量的增加显著提高了土壤净氮矿化率。大气氮沉积的变化占整个森林土壤净氮矿化率变化的48%。
{"title":"Investigation of in situ soil nitrogen mineralization in a Picea-Abies forest in Tibet Plateau: effects of increased nitrogen input","authors":"Ge Wang, Lin Han, Xinying Tang, Yu Yang","doi":"10.4154/gc.2019.27","DOIUrl":"https://doi.org/10.4154/gc.2019.27","url":null,"abstract":"The main objective of this study was to quantify the dynamics of ammonium (NH4+) and nitrate (NO3-) in the humus (0-7cm) and the uppermost mineral layer (0-15cm) of a forest soil. The soil was treated annually from 2012 to 2013 with one single dose of nitrogen (0, 15, 30kg N ha-1yr-1 applied as (NH4)2SO4, NH4Cl, KNO3). Net N mineralization, including net ammonification and net nitrification was determined in four in situ incubation periods over 2 years in a Picea-Abies forest stand at the Qinghai-Tibet Plateau, Southwest China. Measurements were done using soil cores (7cm or 15cm deep) with a resin bag filled with combined anion and cation exchange resins placed at the base to collect the N leaching from the soil. The accumulation rate of N was corrected for both deposition and fertilizer N inputs. In all treatments, both the content and accumulation of the mineral N were dominated by NH4+ which accounts for about 76-89% of the net mineralization. The accumulation rate of N decreased to 64-83% in KNO3 treatments. The net N mineralization rate increased with nitrogen input, especially in NH4+-N treatments (p<0.05). However, this promoting role decreased over time. At the highest (NH4)2SO4 additions, the net ammonification and net mineralization rate increased notably in the humus (0-7cm) rather than in the uppermost mineral layer (0-15 cm). Previous studies that reported on soil net mineralization from forests under different environmental conditions were compiled and assessed for the effects of atmospheric N deposition and environmental factors, annual precipitation, and annual temperature on annual fluxes of net nitrogen mineralization in forest soils, worldwide. The results show that an increase in atmospheric N deposition significantly enhances the soil net nitrogen mineralization rate. Variation in atmospheric N deposition accounts for 48% of the variation in the rate of soil net nitrogen mineralization across the forests.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"145-153"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49109266","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}
Stability assessment of rock slopes in hydropower engineering regions is an important and complex issue. Rock mass classification systems are a good approach because they can thoroughly consider many factors influencing rock slope stability. The slope stability probability classification (SSPC) system is a novel method. However, it has two limitations when applied to rock slopes: 1) it is only suitable for slopes less than 45 m in height, and 2) there is great subjectivity and randomness in the estimation of intact rock strength. Therefore, this study presents two modifications of the SSPC system by adopting the Hoek-Brown strength criterion and an empirical formula for maximum slope height. Evaluation of results from of 34 typical rock slopes of the major hydropower engineering regions in China indicated that the accuracy rate of the modified SSPC for stability evaluation of these slopes was 61.8%, and the accuracy for stability evaluation of 10 slopes with non-structural control failure was 80%. The stability values of stable and unstable slopes obtained using the modified SSPC were different to those obtained using the Chinese Slope Mass Rating (CSMR) and modified CSMR systems. In addition, the identification accuracy rate of the modified SSPC was significantly higher than that of the CSMR and modified CSMR. Therefore, the modified SSPC can be applied to hydropower engineering regions, providing a new means of rapidly evaluating the slope stability of high rock slopes (slopes > 45 m in height) in these regions.
{"title":"Modification of slope stability probability classification and its application to rock slopes in hydropower engineering regions","authors":"L. Xiuzhen, Tan Rong-zhi, G. Yan","doi":"10.4154/gc.2019.20","DOIUrl":"https://doi.org/10.4154/gc.2019.20","url":null,"abstract":"Stability assessment of rock slopes in hydropower engineering regions is an important and complex issue. Rock mass classification systems are a good approach because they can thoroughly consider many factors influencing rock slope stability. The slope stability probability classification (SSPC) system is a novel method. However, it has two limitations when applied to rock slopes: 1) it is only suitable for slopes less than 45 m in height, and 2) there is great subjectivity and randomness in the estimation of intact rock strength. Therefore, this study presents two modifications of the SSPC system by adopting the Hoek-Brown strength criterion and an empirical formula for maximum slope height. Evaluation of results from of 34 typical rock slopes of the major hydropower engineering regions in China indicated that the accuracy rate of the modified SSPC for stability evaluation of these slopes was 61.8%, and the accuracy for stability evaluation of 10 slopes with non-structural control failure was 80%. The stability values of stable and unstable slopes obtained using the modified SSPC were different to those obtained using the Chinese Slope Mass Rating (CSMR) and modified CSMR systems. In addition, the identification accuracy rate of the modified SSPC was significantly higher than that of the CSMR and modified CSMR. Therefore, the modified SSPC can be applied to hydropower engineering regions, providing a new means of rapidly evaluating the slope stability of high rock slopes (slopes > 45 m in height) in these regions.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"71-80"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.4154/gc.2019.20","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48068072","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}
Detailed geochemical and U-Pb studies of two diabases (Luoji and Cuiyi) from the Luoji area have been undertaken. The diabases are high-K calc-alkaline and belonging to the tholeiitic series, enriched in large ion lithophile elements, Ti, Zr and light rare earth elements, and depleted in high field strength elements. These characteristics are different from the oceanic island basalt but highly consistent with the continental rift basalt, indicating the Luoji and Cuiyi diabases are the products of the intracontinental rift related to the initial opening of the Ganzi-Litang Ocean. The Luoji and Cuiyi diabases originated from an enriched mantle source with a small degree of crustal contamination during their emplacement. Zircon U-Pb ages show that the Luoji and Cuiyi diabases were emplaced at 293.4 +/- 5.4Ma. Therefore, we propose that the time of initial rifting of the Ganzi-Litang Ocean occurred during the very Early Permian.
{"title":"Geochemistry and U-Pb ages of the diabases from the Luoji area, western Yunnan, China: implications for the timing of initial rifting of the Ganzi-Litang Ocean","authors":"Chan Wang, Hao Liu, H. Feng, Jianghong Deng, Xian-fan Liu, Fufeng Zhao","doi":"10.4154/gc.2019.25","DOIUrl":"https://doi.org/10.4154/gc.2019.25","url":null,"abstract":"Detailed geochemical and U-Pb studies of two diabases (Luoji and Cuiyi) from the Luoji area have been undertaken. The diabases are high-K calc-alkaline and belonging to the tholeiitic series, enriched in large ion lithophile elements, Ti, Zr and light rare earth elements, and depleted in high field strength elements. These characteristics are different from the oceanic island basalt but highly consistent with the continental rift basalt, indicating the Luoji and Cuiyi diabases are the products of the intracontinental rift related to the initial opening of the Ganzi-Litang Ocean. The Luoji and Cuiyi diabases originated from an enriched mantle source with a small degree of crustal contamination during their emplacement. Zircon U-Pb ages show that the Luoji and Cuiyi diabases were emplaced at 293.4 +/- 5.4Ma. Therefore, we propose that the time of initial rifting of the Ganzi-Litang Ocean occurred during the very Early Permian.","PeriodicalId":55108,"journal":{"name":"Geologia Croatica","volume":"72 1","pages":"19-32"},"PeriodicalIF":1.3,"publicationDate":"2019-12-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42678226","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}
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