Erosion of geological units and sediment load in rivers can be considered as the serious problems in recent decades.Increasing sediment loads generate major hazards for water resources development,particularly in term...Erosion of geological units and sediment load in rivers can be considered as the serious problems in recent decades.Increasing sediment loads generate major hazards for water resources development,particularly in terms of loss of reservoir storage due to sedimentation and siltation of water distribution systems.In this paper,the performance of four sediment rating curve (SRC) development methods was evaluated for the Shirin Darreh River(SDR) basin (1750 km^(2)),located in North Khorasan Province,Iran.Data of flow discharge (Q) and suspended sediment flux (SSF)(Q-SSF pairs,N=957)and daily flow discharge,recorded by the Regional Water Company of North Khorasan (RWCNK) at the Qaleh-Barbar (QB) gauging site during 1989-2018 were used.The flow discharge classification method performed best by meeting the desired criteria of most statistical indices,including normalized root mean square error (NRMSE),mean bias error (MBE),mean absolute error (MAE),index of agreement (d),and coefficient of determination (R^(2)).Based on the optimized method,the rate of suspended sediment transportation at the study site was estimated about2.7×10^(6) ton year^(-1).Erodibility of the exposed formations in the study area was estimated based on a factorial scoring model (FSM).Three indices,focused on the outcrop and erodibility,were calculated for the geological units at sub-basin and total scales.Marl deposits are the most extensive geological unit in the three sub-basins and the maximum formation outcrop ratio (FOR) and participation in erosion (PCE)were obtained for these rocks at total scale.In fact,marl unit can be regarded as the main source to supply the suspended sediments in the study basin.展开更多
Taking the problems and countermeasures in financial management of geological prospecting units as the research object, this paper first discusses the necessity of strengthening financial management of geological pros...Taking the problems and countermeasures in financial management of geological prospecting units as the research object, this paper first discusses the necessity of strengthening financial management of geological prospecting units, then discusses some problems in the current management process of geological prospecting units, and finally puts forward some targeted solutions, hoping to provide some reference for related research.展开更多
Under the new normal, geological prospecting units are required to re-examine their current development model, observe the deficiencies in the financial management process, and take this as a guide to transform, upgra...Under the new normal, geological prospecting units are required to re-examine their current development model, observe the deficiencies in the financial management process, and take this as a guide to transform, upgrade and optimize the management model. This requires geological prospecting units to grasp the direction and focus of the transformation, for example, from the aspects of budget execution, supervision and audit to strengthen the control of financial management of enterprises, and effectively play the macro guidance and control role of the units, so as to play a greater value and effectiveness of the financial management model. This paper discusses and analyzes the necessity and ways of the transformation of the financial management mode of geological prospecting units under the new normal.展开更多
The geological-geophysical map series of the eastern China seas and adjacent region （1：1 000 000） will be published in the late half year of 2009. The regional tectonic map is one of the main professional maps. The...The geological-geophysical map series of the eastern China seas and adjacent region （1：1 000 000） will be published in the late half year of 2009. The regional tectonic map is one of the main professional maps. The Mapping methods, the division method of geological tectonic units and the main geological tectonic units are mainly discussed. The strata from Pliocene to Holocene are peeled off so as to display the Pre-Pliocene structures. In basins, isopaches are drawn for the Cenozoic deposits. The plate tectonic theory and present tectonic pattern are adopted as the priorities in tectonic division. As to the division of intraplate tectonic units, it is a revision, complement and improvement of previous dividing systems, and the nomenclature for each tectonic unit follows the current system in China. The first-order tectonic unit is plate （Pacific Plate, Eurasian Plate and Philippine Sea Plate）. The second-order tectonic unit is tectonic domain （East Asian continental tectonic domain,East Asian continental margin tectonic domain and west Pacific tectonic domain）. The Philippine Sea Plate and the west part of the Pacific Plate are called the West Pacific tectonic domain. The part of the Eurasian Plate involved in this study area can be further divided into East Asian continental tectonic domain and East Asian continental margin tectonic domain. The East Asian continental margin domain is composed of the Ryukyu island arc, the Okinawa Trough back-arc basin and the back-arc basin of Sea of Japan. The East Asian continental tectonic domain in this study area is composed of the Sino-Korea Massif, the Changjiang River （Yangtze） Massif and South China Massif. In turn, these massifs consist of basins, folded belts or uplift zones. The basins,the folded belts or the uplift zones are further divided into uplifts and depressions made up of sags and swells.展开更多
The crust of the Moon records the complete history of collisions by different-sized projectiles from various sources since its early solidification.Planetary bodies in the inner Solar System experienced similar source...The crust of the Moon records the complete history of collisions by different-sized projectiles from various sources since its early solidification.Planetary bodies in the inner Solar System experienced similar sources of impactors,and the Moon is an ideal witness plate for the impact history.Impact flux on the Moon connects planetary endogenic evolution with orbital dynamics of celestial bodies,and the resulting crater chronology enables remote age estimation for geological units on extraterrestrial bodies.Therefore,defining the lunar impact history has long been a core pursuit in planetary sciences.Ubiquitous impact structures on the Moon and their widespread impact melt deposits are the major agents used to untangle lunar crater chronology.Anchored by 10 successful sample return missions from the Moon,cumulative crater densities were derived for 15 geological units based on their interpreted exposure ages(~3.92 Ga to 25 Ma)and superposed crater densities.Afterword,crater production rates in the entire history of the Moon were constructed on the basis of hypothesized change patterns of impact flux.Following this commonly adapted strategy,it has been a consensus that impact flux in the first billion years of the lunar history was orders of magnitude larger than that afterward,and the latter was not only more or less stable but also punctuated by discrete spikes.However,different versions of lunar crater chronology exist because of insufficient constraints by available anchor points and widespread disagreements on both sample ages and crater densities of existing anchor points.Endeavors from various disciplines(e.g.,sample analyses,remote observation,and modeling crater formation and accumulation)are making promising progresses,and future sample return missions with both optimized sampling strategy and analyzing techniques are appealed to fundamentally improve the understanding of lunar impact flux.展开更多
基金This study was conducted as the research project(Doctoral Dissertation),supported by the Ferdowsi University of Mashhad[Grant number 3/47984(contribution of the first author(M.T))]approved on 11.7.2018。
文摘Erosion of geological units and sediment load in rivers can be considered as the serious problems in recent decades.Increasing sediment loads generate major hazards for water resources development,particularly in terms of loss of reservoir storage due to sedimentation and siltation of water distribution systems.In this paper,the performance of four sediment rating curve (SRC) development methods was evaluated for the Shirin Darreh River(SDR) basin (1750 km^(2)),located in North Khorasan Province,Iran.Data of flow discharge (Q) and suspended sediment flux (SSF)(Q-SSF pairs,N=957)and daily flow discharge,recorded by the Regional Water Company of North Khorasan (RWCNK) at the Qaleh-Barbar (QB) gauging site during 1989-2018 were used.The flow discharge classification method performed best by meeting the desired criteria of most statistical indices,including normalized root mean square error (NRMSE),mean bias error (MBE),mean absolute error (MAE),index of agreement (d),and coefficient of determination (R^(2)).Based on the optimized method,the rate of suspended sediment transportation at the study site was estimated about2.7×10^(6) ton year^(-1).Erodibility of the exposed formations in the study area was estimated based on a factorial scoring model (FSM).Three indices,focused on the outcrop and erodibility,were calculated for the geological units at sub-basin and total scales.Marl deposits are the most extensive geological unit in the three sub-basins and the maximum formation outcrop ratio (FOR) and participation in erosion (PCE)were obtained for these rocks at total scale.In fact,marl unit can be regarded as the main source to supply the suspended sediments in the study basin.
文摘Taking the problems and countermeasures in financial management of geological prospecting units as the research object, this paper first discusses the necessity of strengthening financial management of geological prospecting units, then discusses some problems in the current management process of geological prospecting units, and finally puts forward some targeted solutions, hoping to provide some reference for related research.
文摘Under the new normal, geological prospecting units are required to re-examine their current development model, observe the deficiencies in the financial management process, and take this as a guide to transform, upgrade and optimize the management model. This requires geological prospecting units to grasp the direction and focus of the transformation, for example, from the aspects of budget execution, supervision and audit to strengthen the control of financial management of enterprises, and effectively play the macro guidance and control role of the units, so as to play a greater value and effectiveness of the financial management model. This paper discusses and analyzes the necessity and ways of the transformation of the financial management mode of geological prospecting units under the new normal.
基金The National Natural Science Foundation of China under contract No 40876033the foundation of Geological Investigation Bureau of China under contract No HY126-03
文摘The geological-geophysical map series of the eastern China seas and adjacent region （1：1 000 000） will be published in the late half year of 2009. The regional tectonic map is one of the main professional maps. The Mapping methods, the division method of geological tectonic units and the main geological tectonic units are mainly discussed. The strata from Pliocene to Holocene are peeled off so as to display the Pre-Pliocene structures. In basins, isopaches are drawn for the Cenozoic deposits. The plate tectonic theory and present tectonic pattern are adopted as the priorities in tectonic division. As to the division of intraplate tectonic units, it is a revision, complement and improvement of previous dividing systems, and the nomenclature for each tectonic unit follows the current system in China. The first-order tectonic unit is plate （Pacific Plate, Eurasian Plate and Philippine Sea Plate）. The second-order tectonic unit is tectonic domain （East Asian continental tectonic domain,East Asian continental margin tectonic domain and west Pacific tectonic domain）. The Philippine Sea Plate and the west part of the Pacific Plate are called the West Pacific tectonic domain. The part of the Eurasian Plate involved in this study area can be further divided into East Asian continental tectonic domain and East Asian continental margin tectonic domain. The East Asian continental margin domain is composed of the Ryukyu island arc, the Okinawa Trough back-arc basin and the back-arc basin of Sea of Japan. The East Asian continental tectonic domain in this study area is composed of the Sino-Korea Massif, the Changjiang River （Yangtze） Massif and South China Massif. In turn, these massifs consist of basins, folded belts or uplift zones. The basins,the folded belts or the uplift zones are further divided into uplifts and depressions made up of sags and swells.
基金supported by the National Natural Science Foundation(42241108,42273040,12203036,and L2224032)B-type Strategic Priority Program of the Chinese Academy of Sciences(XDB41000000)+1 种基金the National Key Research and Development Program of China(grant no.2022YFF0503100)Chinese Academy of Sciences(XK2022DXC004).
文摘The crust of the Moon records the complete history of collisions by different-sized projectiles from various sources since its early solidification.Planetary bodies in the inner Solar System experienced similar sources of impactors,and the Moon is an ideal witness plate for the impact history.Impact flux on the Moon connects planetary endogenic evolution with orbital dynamics of celestial bodies,and the resulting crater chronology enables remote age estimation for geological units on extraterrestrial bodies.Therefore,defining the lunar impact history has long been a core pursuit in planetary sciences.Ubiquitous impact structures on the Moon and their widespread impact melt deposits are the major agents used to untangle lunar crater chronology.Anchored by 10 successful sample return missions from the Moon,cumulative crater densities were derived for 15 geological units based on their interpreted exposure ages(~3.92 Ga to 25 Ma)and superposed crater densities.Afterword,crater production rates in the entire history of the Moon were constructed on the basis of hypothesized change patterns of impact flux.Following this commonly adapted strategy,it has been a consensus that impact flux in the first billion years of the lunar history was orders of magnitude larger than that afterward,and the latter was not only more or less stable but also punctuated by discrete spikes.However,different versions of lunar crater chronology exist because of insufficient constraints by available anchor points and widespread disagreements on both sample ages and crater densities of existing anchor points.Endeavors from various disciplines(e.g.,sample analyses,remote observation,and modeling crater formation and accumulation)are making promising progresses,and future sample return missions with both optimized sampling strategy and analyzing techniques are appealed to fundamentally improve the understanding of lunar impact flux.
