Environment change of Sihu Lake in the past 450 years, southern China

In recent years, climate and environment changes since the Little Ice Age have become a focus in modern research. The paper selected the sediment (77 cm) of Sihu Lake, which was located in Guilin, southern China, as the research object and analyzed the karst wetland environmental changes within nearly 450 years. According to the vertical profile of indicators and geochemical elements in sediment core, the regional environmental evolution was divided into four stages. The former two stages were mainly influenced by Little Ice Age (1562–1895). The third stage climate has changed slowly. The fourth stage was mainly affected by human activities and global warming. The factor analysis of geochemical elements indicated that karst wetland regional environmental change was affected by four major factors. In the 53–77 cm stage (1562–1703), F1 (erosion factor), F2 (watershed runoff and diagenesis factor) and F3 (regional background factor) were reduced, indicating that it was in cold and dry stage of Little Ice Age. In the 20–53 cm stage (1703–1895), F1 and F2 increased, indicating that it was in cold and wet stage of Little Ice Age. In the 4–20 cm stage (1895–1987), F1, F2 and F4 (human activity factor) increased slowly, indicating that the climate was affected by global warming and more precipitation. In the 0–4 cm stage (1987–2007), F1 and F2 reduced and F4 increased, indicating the reduced precipitation, rising temperature and more impact of human activities. In addition, it was proposed that the Little Ice Age in Guilin District in southern China started in the 1560s and lasted until the 1895s or so.     

Climate and environmental changes over the past 150 years inferred from the sediments of Chaiwopu Lake, central Tianshan Mountains, northwest China

We used a 55-cm sediment core from shallow Chaiwopu Lake in the central Tianshan Mountains of Xinjiang, northwest China, to investigate climate and environmental changes in this arid region over the past ~150 years. The core was dated using ¹³⁷Cs. We compared temporal changes in several sediment variables with recent meteorological and tree-ring records. Organic matter had a positive correlation with the Palmer Drought Severity Index in the central Tianshan Mountains, and the δ¹³C of organic matter had a positive correlation with regional temperature. We applied constrained incremental sum-of-squares cluster analysis to element concentrations in the core and identified three distinct zones: (1) 55–46 cm, ~1860–1910, (2) 46–26 cm, ~1910–1952, and (3) 26–0 cm, 1952–present. Between 1880 and 1910 AD, following the Little Ice Age (LIA), the sediment environment was relatively stable, climate was cold and dry, and the lake water displayed high salinity, in contrast to conditions during the LIA. During the LIA, westerlies carried more water vapor into Central Asia when the North Atlantic Oscillation was in a negative phase, and encountered the enhanced Siberia High, which probably led to increased precipitation. In the period 1910–1950 AD, the lake was shallow and the regional climate was unstable, with high temperatures and humidity. In the last ~15–20 years, human activities caused an increase in sediment magnetic susceptibility, and heavy metal and total phosphorus concentrations in the sediment were substantially enriched. Mean annual temperature displays a warming trend over the past 50 years, and the lowest temperature was observed in the 1950s. There has been an increase in annual total precipitation since the 1990s. The combined influences of climate and human activity on the lake environment during this period were faithfully recorded in sediments of Chaiwopu Lake. This study provides a scientific basis for environmental management and protection.     

Streamflow changes and its influencing factors in the mainstream of the Songhua River basin,Northeast China over the past 50 years

The Songhua River plays a key role in the national development of China, owing to its unique natural condition and resources. Recent changes in the streamflow in the Songhua River are important with regard to local sustainable development and management under the background of global warming and aggravating soil erosion. In order to detect changes in the streamflow, two streamflow series from 1955 to 2004 (observed at the Harbin and Jiamusi stations) in the mainstream of Songhua River basin were obtained, and methods of statistical analysis, wavelet transform, and double mass analysis were employed to analyze the data. Reasons for the changes to the streamflow are discussed with respect to natural and man-made drivers. The results show the following: (1) From 1955 to 2004, the streamflow series present obvious declining trends. (2) The streamflow series followed the pattern of a wet–dry–wet–dry cycle pattern over the past 50 years. In the mainstream of Songhua River, wet years mainly occurred during the periods of 1955–1966 and 1984–1993, while dry years mainly occurred in the 1970s and after 2000. (3) Within the 50-year scale, the streamflow series appeared in the main periods of circa 33-, 13- and 4-year, in which the 33-year periodicity is the strongest. (4) Precipitation and temperature directly influenced the streamflow in the mainstream of the basin. The discharge was positively correlated with the precipitation and negatively correlated with the temperature. In addition, human activity was another important driving factor for streamflow change. (5) In the mainstream of Songhua River basin, the influences on streamflow can be divided into three periods: 1955–1976, 1977–1997, and 1998–2004. In the first period climate change played a dominant role, and during the latter two periods human influences were enhanced significantly.     

Hydrological situation of a typical watershed in the Loess Tableland Area of China over the past 30 years

Due to deficient water resources in the Loess Plateau, watershed management plays a very important role, not only for ecological and environmental protection but also for the social development of the region. To better understand the hydrological and water resource variations in the typical watershed of the Loess Plateau and the Qinghe River Basin, the influences of land cover and climate change were analysed, and a SWAT model was built to simulate the response of the hydrological situation to land cover changes that have occurred over the past 30 years. The results demonstrated that the main land cover change occurring in the Qinghe River Basin was the conversion of land cover from grassland to woodland and farmland from the late 1980s to 2010. Woodland and farmland took 87.36 and 10.55%, respectively, from the overall area transferred over 20 years and more than 18% of the total watershed area. Hydrological simulation results indicated that land cover played a predominant role in the hydrological variation of the Qinghe River Basin, although the effects of climate change should not be discounted. The significant changes in land cover could be superimposed by policy orientation and economic requirements. Although it is hard to evaluate the land cover changes and the corresponding hydrological responses in a simple language, related analyses have demonstrated an increasing trend of runoff in the dry season, while there is a somewhat decreasing trend during the flood season in the river basin. There results could be significant and provide a positive influence on both future flood control and the conservation of water and soil.     

Lake Sequence Stratigraphy of the Shahejie Formation in the Zhanhua Hollow, Shandong Province

Two sequences can be identified in the sedimentary strata of the lower Tertiary ShahejieFormation in the Zhanhua hollow. The lowstand, lake-transgressive and highstand systemstracts were formed under the control of ancient structure, palaeotopography, palaeoclimate, sed-iment supply, marine-transgression, and so on. In the paper the authors present a composite se-quence stratigraphical section of the Shahejie Formation in this area, and expound the bounda-ries of parasequences, parasequences set and systems tracts and evolutions of lake sequencestratigraphy and sedimentology and discuss various factors controlling the lake level fluctuation.The differences between lake and marine sequence stratigraphy are also indicated in the paper.The lake sequence stratigraphical study should be based on a synthetic analysis of structural evo-lution, palaeomagnetism, palaeoclimatic changes, geological Well logs, seismic and logging data,palaeontological data, global sea level changes, and so on. The sequence stratigraphical evolutionis closely related to the formation, development and elimination of the whole basin and thesedimentary process.     

Human Influence on Heavy Metal Distribution in the Upper Lake Nansi Sediments, Shandong Province, China

Core and surface sediment samples were collected from three sub-lakes ( Lake Nanyang, Lake Dushan and Lake Zhaoyang) in the Lake Nansi Basin, Shandong Province. In order to reveal the characteristics of spatial and historical distribution of heavy metals in different sublakes of the Upper Lake Nansi, heavy metal (As, Cr, Cu, Hg, K, Mn, Ni, Pb, Zn, Al, Fe, Ti and V) concentrations of sediment samples were investigated. Based on the activity of^137Cs in the sediments, the modem accumulation rate of Lake Nansi sediments is 3.5 mm/a. Our results show that the whole Upper Lake Nansi has been already polluted by heavy metals, among which Lake Nanyang has been polluted seriously by mercury, as well as by lead and arsenic, while Lake Dushan has been most seriously polluted by lead and arsenic. Historical variation of heavy metal (Cr, Cu, K, Ni, Zn, A1, Fe, Ti and V) concentrations shows an abrupt shift in 1962, resuiting in a division of two periods: from 1957 to 1962 when metal enrichment increased with time, and from 1962 to 2000 when it decreased with time, while that of some anthropogenic elements such as Hg, Pb and Mn tend to increase toward the surface. However, the variation trend of As in the sediments is different from that of Hg, Pb and Mn, with its maximum value appearing in 1982. Since 1982 the concentrations of As have decreased due to the forbidden use of arsenite pesticides. This variation trend revealed changes in manner of human activity (coal combustion, waste discharges from both industries and urban sewage ) within the catchment during different periods.     

Structural geochemistry of gold mineralization in the Linglong-Jiaojia district, Shandong Province, China

The Linglong-Jiaojia district is one of the most important regions containing gold deposits in China. These gold deposits can be divided into: a) the pyrite-gold-quartz vein type (Linglong type), which is controlled by brittle-ductile to ductile deformation structures, and b) the alteration-zone type (Jiaojia type), characterized by small veinlets, or the disseminated type recognized in brittle shear zones. Lode gold deposits in the Jiaojia area occur in NE brittle fracture zones, formed in a dominantly simple shear deformation regime, mainly in thrust attitude with a minor sinistral strike slip component. In the Linglong area, the lode gold deposits are located at the intersection of three types of structures: NNE and NE brittle-ductile fault zones and the ENE ductile reverse shear zone in the south of the area. The structural characteristics of these brittle shear zones are consistent with a tectonic NNW-SSE principal stress field orientation. Similar stresses explain the ENE Qixia fold axes, the Potouqing and several other ENE reverse ductile shear zones elsewhere in the region, the Tancheng-Lujiang fault zone and its subsidiaries in the vicinity of the Linglong-Jiaojia district, as well as the southern ENE suture zone north of Qingdao. Therefore these structural systems occurred as part of different major tectonic events under NNW-SSE compression principal stress fields in the area. Gold deposits are hosted in smaller-scale structures within the brittle fault zones and brittle-ductile shear zones. Although ore bodies and, on a smaller scale, quartz ore veins often seem to be randomly oriented, it is possible to explain their distribution and orientation in terms of the simple shear deformation process under which they were developed. The progressive simple shear failure is characterized by various fracture modes (tension and shear) that intervene in sequence. The tension and shear fractures are influenced by the stress level (depth of burial beneath the paleosurface) in their structural behavior, show variable dilatancy (void openings) and extend on all scales. By making use of these characteristics, a progressive failure analysis can be applied to predicting the shape and extent of ore bodies as well as the styles of mineralization at any given location.     

Study on rainfall variations in the middle part of Inner Mongolia,China during the past 43 years

The study area, the middle part of Inner Mongolia including Hohhot city, Baotou city, Wulanchabu city, Ordos city, Bayannaoer city and Wuhai city, is one of typical eco-geographical transition zones in China. Using monthly precipitation data (1961–2003) from 45 meteorological stations in the study area, this paper analyzes characteristics and tendencies of annual and seasonal rainfall variations, and reveals multi-time scales structures of these time series through wavelet analyses; also, the periods of annual and seasonal precipitation series are identified, and the periodical oscillations and points of abrupt change at the principal period scale are discovered. The results show that annual precipitation varies in a large range, and has an ascending tendency at an increasing rate of 1.482 mm/10a; the multi-time scales periodical oscillations are clear; differences in tendencies, ranges and decadal precipitation anomalies exist within each decade during 1961–2000. The seasonal allocation of overall annual precipitation is extremely uneven; in terms of tendencies of seasonal precipitation, winter and spring have upward trends while summer and autumn have downward tendencies; distinctions in tendencies, ranges and decadal precipitation anomalies among each seasons are in existence within each decade during 1961–2000. The periodical oscillations of each seasonal precipitation time series are also evident. The research results not only provide convincing evidence for global climate change research, but also facilitate the understanding of specific natural process and pattern to make steps to rehabilitate and reconstruct vegetation, and contribute to fulfill the sustainability of water management.     

Environmental geochemistry of arsenic in sediment-water interface of Poyang Lake, China

Environmental pollution is one of the vertical problems faced in the 21 century. There are numbers of lakes located in China. Poyang Lake, which is the largest freshwater lake in China, is the famous representation. The environmental geochemistry of trace and ultra-trace element As in the sediment-water interface （SWI） of Poyang Lake was investigated in detail. Solutions presented in the project can be summarized as follows： it is the first time to discover that the ：nasking agent of 8-hydroxyquinoline was found to be an efficient agent to eliminate the interference of transition metals in the determination of arsenic species, especially to eliminate As （Ⅴ） emission with high selection in the matrix of As （Ⅲ） and As （Ⅴ） coexisting solution. A sensitive and interference-free procedure has been successfully established for the arsenic speciation on As （Ⅲ）, As （Ⅴ）, Asorg in pore water samples using flowing injection hydride generation atomic fluorescence spectrometry （FI-HG-AFS）. It was observed that the concentrations of arsenic species in porewaters were relatively high. With the variation of the redox in sediments, it is easy to cause the second pollution in overlying waters for their upward diffusion. Arsenic is mainly absorbed onto iron and manganese oxyhydroxides in controlling the behavior of As. The effect factors of the transfer, cycle of arsenic are the redox condition at SWI, disturbance, and microbial action, etc.     

Enzymatic and Microbial Degradation of Organic Matter in Lake Hongfeng, Guizhou Province, China

1IntroductionEnzymaticandmicrobialdegradationoforganicmatterhasabearingnotonlyonearlydiagene sis,butalsoonelementcyclingandmicrobedistributioninlakesediments.Somereportsshowedtheabundancevariationsoforganicmatterinsediments (BurdigeandGardner,1998;ArthurandDean ,1998;WanGuojiangetal.,2 0 0 0 ) .However,duetothecomplexchemicalcompositionoforganicmatter,mechanismsofenzymaticandmicrobialdegradationandvariationsofeachchemicalcomponentneedtobestudiedfurther.Underanoxiccondition ,SO2 -4 isanimpo…     

Discovery of the Archean Magmatic Cu-Ni Sulfide Deposit in China—Taoke Deposit,Shandong Province

The formation ages of global magmatic sulfide Ni-Cu deposits are from Archean to Mesozoic,the Neoarchean and Neoproterozoic are the two peaks.In China,the formation ages of magmatic sulfide deposits are from Proterozoic to Mesozoic,and the Neoproterozoic and late Paleozoic are the two peaks,.Compared with the global magmatic deposits,there is no case study of the Archean magmatic Ni-Cu sulfide deposits in China before.The nickel deposits formed in Neoproterozoic are located on the margin of the North China Block and Yangtze Block(e.g.Jinchuan,Dapoling),and those formed in the late Paleozoic are mainly distributed in the Central Asian Orogenic Belt(CAOB).Emeishan and Tarim Large Igneous Provinces(LIPs).such as Kalatongke,Yangliuping,and Pobei.     

Assessment of nutrient sources and paleoproductivity during the past century in Longgan Lake, middle reaches of Yangtze River, China

A 63-cm sediment core documents that the concentrations of nutrients in sediment, such as organic carbon, nitrogen and phosphorous, continually increased during the last century in Longgan Lake, middle reaches of the Yangtze River, China. C/N ratio and δ^13Corg revealed that organic matter in the sediment derived mainly from aquatic and terrestrial sources is a minor contributor. Excess phosphorous is related to human activities marked by utilization of phosphoric fertilizers since 1952 A.D. The increase of δ^13Corg towards the sediment surface, together with increasing of OC and N accumulation, indicated the elevation of lake primary productivity due to excess phosphorous loading caused by utilization of phosphoric fertilizer. The decrease of δ^15N during the primary productivity elevation process, especially after 1952, can be attributed to the discharged of nitrogen with lower δ^15N into the lake.     

Neogene Paleoseismic Events and the Shanwang Biota’s Burial in the Linqu Area, Shandong Province, China

Several paleoseismic events are recorded in the Neogene Linqu Group, exposed in the Linqu area, Shandong Province, China. The events were interpreted on the basis of fieldwork and laboratory analysis, which showed the presence of seismites with plastically deformed soft-sediment deformation structures in the Shanwang Formation, and of seismic volcanic rocks in the Yaoshan Formation which show brittle deformation. The earthquake-triggered soft-sediment deformations in the seismites include load structures, ball-and-pillow structures, flame structures, pillow-like beds, boudinage structures, slump folds, syn-depositional faults, veins of liquefied sand, and dikes of liquefied sandy lime-mud. The seismic activity is also reflected in what might be called ‘brittle seismites'; these originated when, under the influence of seismic vibrations, semi-consolidated conglomerate was shattered. Moreover, volcanic activity is related to intense earthquakes that affected basalts intercalated with sand layers; these successions are known as ‘seismic volcanic rocks', which are characterized by veins of liquefied sand intruding the basalts. All above traces of paleoseismic activity were left from one single time span of 4 Ma with active seismicity that took place 14–10 Ma. This time span is known as ‘the Linqu Neogene Paleoseismic Active Period', which is divided into four paleoseismic episodes, which were responses to tectonic extension and basin rifting in this area. It even includes the activity of the Yishu Fault Zone during the Miocene and the Neogene. The ratios of trace elements in the seismites, w(La)/w(Sc) and w(La)/w(Th) are higher than the average value of the upper crust, but w(Th)/w(Sc) is lower; this is geochemical evidence for the basin rifting that resulted in a high sedimentation rate. The intense and frequent paleo-earthquakes are held responsible for the rapid burial of the Shanwang Biota. Secondary earthquake-induced processes(e.g. slumping of a lake shore and the strongly increased lacustrine sedimentation rate) contributed to the rapid burial of the biota.     

Environmental Geochemistry of Swan Lake Inlet,Rongcheng Bay,the Yellow Sea of China

The Swan Lake Inlet, the State Primary Wildlife Protection Area, is a lagoon-inlet system located in the Rongcheng Bay, Shandong Peninsula, China. It has been undergoing development for aquaculture and tourism. In the summer of 1999, a study on the environment of the Swan Lake Inlet was carried out. The concentrations of the major elements and trace elements Fe, Al, Pb, Zn, Cd, Cu, Cr, Mn and P have been measured by ICP-AES and graphite furnace atomic adsorption spectrometry. The sources and distribution of the elements in the Swan Lake Inlet have been discussed. It is concluded that the Swan Lake Inlet has not been subjected to significant environmental pollution. The chemical results show that the dissolved oxygen (DO) contents are generally normal. At some locations DO solubility appears to be >100 %. The BOD₅ ( five-day biochemical oxygen demand) values are generally <4 mg/L and COD (chemical oxygen demand) 3～4 mg/L. The seawater N, P and Si contents are lower than the Class I water type specified by the Chinese National Standard of Water Quality. The low nutrient distribution reflects little discharge from land, therefore lacking of nutrient supply.     

Hydrogeochemical characteristics of groundwater and pore-water and the paleoenvironmental evolution in the past 3.10 Ma in the Xiong’an New Area,North China

The groundwater level has been continuously decreasing due to climate change and long-time overexploitation in the Xiong’an New Area, North China, which caused the enhanced mixing of groundwater in different aquifers and significant changes in regional groundwater chemistry characteristics. In this study, groundwater and sediment pore-water in drilling cores obtained from a 600 m borehole were investigated to evaluate hydrogeochemical processes in shallow and deep aquifers and paleo-environmental evolution in the past ca. 3.10 Ma. Results showed that there was no obvious change overall in chemical composition along the direction of groundwater runoff, but different hydrochemical processes occurred in shallow and deep groundwater in the vertical direction. Shallow groundwater (< 150 m) in the Xiong’an New Area was characterized by high salinity (TDS > 1000 mg/L) and high concentrations of Mn and Fe, while deep groundwater had better water quality with lower salinity. The high TDS values mostly occurred in aquifers with depth < 70 m and >500 m below land surface. Water isotopes showed that aquifer pore-water mostly originated from meteoric water under the influence of evaporation, and aquitard pore-water belonged to Paleo meteoric water. In addition, the evolution of the paleoclimate since 3.10 Ma BP was reconstructed, and four climate periods were determined by the δ¹⁸O profiles of pore-water and sporopollen records from sediments at different depths. It can be inferred that the Quaternary Pleistocene (0.78–2.58 Ma BP) was dominated by the cold and dry climate of the glacial period, with three interglacial intervals of warm and humid climate. What’s more, this study demonstrates the possibilities of the applications of pore-water on the hydrogeochemical study and further supports the finding that pore-water could retain the feature of paleo-sedimentary water.© 2021 China Geology Editorial Office.     

Spatial–temporal evolution of ore-forming fluids and related mineralization in the western Lanping basin,Yunnan Province,China

The Lanping basin is a significant Pb–Zn–Cu–Ag mineralization belt in the Sanjiang Tethyan metallogenic province. A series of sediment-hosted Himalayan Cu–Ag–Pb–Zn polymetallic deposits have been discovered in the western part of the basin, controlled by a thrust–nappe system. In the thrust–nappe system, the Cu orebodies mainly occur in the western and relatively deep part of the mineralization system (the root zone), whereas the Pb–Zn–Ag (± Cu) orebodies occur in the eastern and relatively shallow part of the system (the front zone), both as vein-type mineralization.In this paper we present new data, combined with existing data on fluid inclusions, isotopes and geologic characteristics of representative deposits, to provide the first study that contrasts mineralizing fluids in the Cu–Ag (Mo) and Pb–Zn–Ag (Cu) polymetallic deposits.Fluid inclusion and isotope studies show that the Cu–Ag (Mo) mineralization in the root zone formed predominantly from deep crustal fluids, with the participation of basinal brines. The deep crustal fluids are marked by high CO₂ content, relatively high temperatures (280 to 340 °C) and low salinities (1 to 4 wt.% NaCl equivalent), whereas the basinal brine shows relatively low temperatures (160 °C to 220 °C) and high salinities (12 to 22 wt.% NaCl equivalent), containing almost no CO₂. In comparison, hydrothermal activity associated with the Pb–Zn–Ag (± Cu) deposits in the front zone is characterized by basinal brine, with relatively low temperatures (130 °C to 180 °C), high salinities (9 to 24 wt.% NaCl equivalent), and low CO₂ concentrations. Although evolved meteoric waters have predominantly been proposed as the source for deep crustal fluids, magmatic and metamorphic components cannot be completely excluded. The basinal brine was predominantly derived from meteoric water.The δ³⁴S values of sulfides from the Cu–Ag (Mo) deposits and Pb–Zn–Ag (± Cu) deposits range from − 17.9 to 16.3‰ and from 2.5 to 11.2‰, respectively. These ranges may relate to variations in physicochemical conditions or compositional variation of the sources. Lead isotope compositions indicate that the ore-forming metals were predominantly derived from sedimentary rocks of the Lanping basin.     

High-resolution sedimentary record of lead in the coastal mud of the East China Sea in the past one hundred and fifty years

In the East China Sea （ECS）, there are some mud areas, including the south coastal mud area, the north coastal mud area, and the mud area to the southwest of Cheju Island. X-ray fluorescence （XRF） techniques and Thermal Ionization Mass Spectrometry （TIMS） were used to study the high-resolution sedimentary record of Pb concentrations and Pb stable isotopic compositions in the past one hundred and fifty years in the coastal mud of the ECS. Pb concentrations of a ^210Pb dating S5 core in the study area have increased rapidly since 1980, and reached the maximal value with 65.08 μg/g in 2000, corresponding to the fast economic development of China since the implementation of the ＂Reform and Open Policy＂ in 1978; ^206Pb/^207Pb ratios generally had stabilized at 1.195 from 1860 to 1966, and decreased gradually from 1966 to 2000, indicating that the anthropogenic source Pb contribution to the ECS has increased gradually since 1966, especially since 1980. Pb concentrations decreased distinctly from 2000 to 2003 and ^206Pb/^207Pb ratios increased from 2001 to 2003, corresponding closely to the ban of lead gasoline from 2000 in China. From 1950 to 2003, there occurred four distinct decrease events of ^206Pb/^207Pb, possibly responding to the Changjiang River （Yangtze River） catastrophic floods in 1998, 1991, 1981 and 1954; from 1860 to 1966, there were two decrease periods of ^206Pb/^207Pb, which may respond to the catastrophic floods of Changjiang River in 1931 and 1935, and 1870. As a result of the erosion and drowning by the catastrophic floods, the anthropogenic lead accumulated in soil and water environments over a long period of time was brought into the Changjiang River, then part of them was finally transported into the ECS, which leads to changes in Pb stable isotopic composition.     

Environmental Assessments of Trace Metals in Sediments from Dongting Lake, Central China

INTRODUCTIONFresh water lakes are one of the planet’s mosti mportant freshwater resources.They support life invarious forms,develop tourism and provide uniquerecreational opportunities.It is also a good source ofthe provision of drinking-water for local communi-ties.Studies on trace elements in rivers,lakes,andsedi ments(Zhou et al.,2004;Gray et al.,2000;Grosheva et al.,2000;Klavins et al.,2000;Aucoinet al.,1999;Bortoli et al.,1998;Elbaz-Poulichet etal.,1996;Johansson et al.,1995;F r…