http://www.sciencedirect.com/science/article/pii/S1674987111001125

<正>Greenstone belts of the eastern Dharwar Craton,India are reinterpreted as composite tectonostratigraphic terranes of accreted plume-derived and convergent margin-derived magmatic sequences based on new high-precision elemental data.The former are dominated by a komatiile plus Mg-tholeiitic basalt volcanic association,with deep water siliciclastic and banded iron formation(BIF) sedimentary rocks.Plumes melted at90 km under thin rifted continental lithosphere to preserve inlraoceanic and continental margin aspects.Associated alkaline basalts record subduction-recycling of Mesoarchean oceanic crust,incubated in the asthenosphere.and erupted coevally with Mg basalts from a heterogeneous mantle plume.Together.komaliites-Mg basalts-alkaline basalts plot along the Phanerozoic mantle array in Th/Yb versus Nb/Yb coordinate space,representing zoned plumes,establishing that these reservoirs were present in the Neoarchean mantle. Convergent margin magmatic associations are dominated by tholeiitic to calc-alkaline basalts eompositionally similar to recent intraoceanic arcs.As well,boninitic flows sourced in extremely depleted mantle are present,and the association of arc basalts with Mg-andesites-Nb enriched basalts-adakites documented from Cenozoic arcs characterized by subduction of young(20 Ma),hot,oceanic lithosphere. Consequently.Cenozoic style "hot" subduction was operating in the Neoarchean.These diverse volcanic associations were assembled to give composite terranes in a subduction-accretion orogen at～2.1 Ga,coevally with a global accretionary orogen at ~2.7 Ga,and associated orogenic gold mineralization. Archean lithospheric mantle,distinctive in being thick,refractory,and buoyant,formed complementary to the accreted plume and convergent margin terranes.as migrating arcs captured thick plumeplateaus. and the refractory,low density.residue of plume melting coupled with accreted imbricated plume-arc crust.     

“Water Consumption” in the Diagenetic Stage and Its Petroleum Geological Significance

Inspired from the anomaly of low pressure in the middle and deep reservoir of the Paleogene in the Jiyang depression, this paper theoritically discusses＂waterconsumption＂of the principal mineral alteration during the diagenetic stage. The preliminary research result shows that ＂water consumption＂ of mineral alteration in the diagenetic stage can make formation water greatly decrease. Relevant formations will be in the stage of low pressure without supply of exterior liquid. Pressure differences between the relevant formations and wall rocks make hydrocarbons enter easily to form the effective reservoir.     

A simulating experiment on the geochemical variation trend at the initial period of meteoric waters converting to underground waters and ore fluids

Experimental studies were undertaken on leaching of sedimentary rocks （ dolomite and sandstone） and Hg, Sb ores by distilled water under the condition of a completely open system （room temperature and room pressure）. The aim is to find whether the halogen elements or metal elements first enter the solution at the early stage of meteoric waters converting to groundwaters and ore fluids, and, at the same time, to understand how and when they enter distilled water solutions from the rocks. The experimental resuhs have shown that F and Cl began to enter the fluids in the initial period of thirty days. With increasing leaching duration, the amounts of the elements that entered the fluids increased steadily. During the period from 120 days to 150 days the amounts increased more drastically, followed a slow increase. It is found that the capability of Cl entering the solutions is much greater than that of F. Hg and Sb were found not to have entered the solutions till 120 days later. During this period of time the pH value of the solutions began to drop. As for Hg and Sb ores, Hg and Sb began to enter the solutions on the 60th or 90th day, greatly ahead of schedule, but the two metallic elements in the rock samples began to enter the solutions 150 days later. Relatively speaking, Hg is more easily leached out than Sb from the rocks. In some rock samples, Sb could be detected in the solutions at the end of the experiment. However, Cu, Pb and Zn had not been detected in the leaching solutions from the beginning to the end of the experiment. In the whole leaching process the pH value of the solutions tend to decrease slowly from 7.1 at the beginning to 6.5 at the end. That is to say, in the interaction between pure water and rock the halogen elements in the rocks were preferentially leached out and then entered the fluids. With increasing water/rock reaction duration and amount of halogen-group elements in the solution and with decreasing pH value of the solution, some active metallic elements began to release in small amounts. This experimental result can explain the source and mechanism of volatile components and trace metals in underground waters. Meanwhile, as for those ore deposits produced by ore fluids derived from meteoric waters, the experimental result is also helpful to the understanding of the geochemical variation trend at the initial stage of conversion of meteoric waters to ore fluids.     

钨在表生作用中的富集模拟实验

The adsorption of tungsten on ferric oxide, manganese dioxide, slate, carbonaceous slate,kaolinite and bentonite in the solutions of pH 4---9 at atmospheric temperatures and pressures has been examined. Experimental results show that acidic solution is in favour of the adsorption of tungsten on the adsorbents. The adsorptivities of these adsorbents for tungsten decrease with increasing pH values for the solutions. Of all the substances joining the expe-riment, Fe2O3 is possessed of the highest adsorptivity and clays of the lowest. Their adsorptivities reduce in the order of Fe2O3, MnO, carbonaceous slate, SiO2, slate and clay in neutral and acidic solutions and of Fe2O3, carbonaceous slate, MnO, slate, clay and SiO2 in alkaline solutions. The adsorption of tungsten on the adsorbents and its pH dependence can be explained by the presence of W(VI) complex cations. The increase of pH results in the reduction of their quantities in the solutions with concomitant diminution of adsorptivity.Experimental data indicate that W shows a strong tendency of concentration during supergene processes in tungsten geochemical provinces. Therefore, it is of particular significance in the formation of tungsten-bearing formations.     

Sealing Features of Fluid-Rock System and its Control on Acidic Dissolution in Cretaceous Sandstone Reservoirs, Kuqa Subbasin

The Cretaceous Bashijiqike Formation is the main gas-bearing strata in the northern structural deformation zone of Kuqa subbasin. The acidic dissolution of this formation arose at 5–4Ma, which corresponds to the late burial stage of the Bashijiqike Formation. Variability of interlayer due to rock composition is negligible. Differentiation of acidic dissolution in sandstones was controlled by difference in amount of exogenous acid fluid from underlying strata. For the absence of sedimentary and structural carrier system between the isolated sandstone reservoirs, most fluid-rock systems show relative sealing feature during later burial stage by sealing feature of formation pressure, geochemical characteristics of formation water and content of diagenetic products in sandstones. Variation of sealing effects for different fluid-rock systems is obvious. The pressure coefficient is inversely proportional to acidic dissolved porosity of sandstone reservoirs, indicating that the variation of sealing effects for fluidrock system mainly controls the differentiation of acidic dissolution.     

Did marine transgression happen in Late Cretaceous period in the southeast of Songliao Basin ？——Discussion from evidence of water chemistry

Cretaceous sediment is considered to be the important oil reservoir in the Songliao Basin, which is dominated by continental fluvial and lacustrine strata. In the past decades, research on whether the marine transgression happened in the Late Cretaceous period in the southeast of the Songliao Basin is always a hotspot in China. Previous studies analyzed the marine biology and geochemistry of sediments to argue if the marine transgression had occurred. However, the geochemistry of formation water which could indicate the paleo-environment has not attracted attention. In this paper, the geochemical variations of formation water between the Chaoyanggou anticline, Changchun anticline and Binxian depression in the southeast of the Songliao Basin are analyzed, then the results by comparisons with chemical properties of sea water indicated： （1） the extensive range of pH values from 6 to 10 concerning the formation water. The ranges of TDS of the formation water are from 1 g/L to 20 g/L, which is less than the value in the seatwater; （2） the level of the element Br, which is an important trace element to indicate the marine sedimentary environment, is lower than that from the sea water. The concentrations of the trace element B fluctuate intensively, probably due to the enhancement of water-rock interaction and the enrichment of organic matter; and （3） ionic ratio of Na/Cl and Br＊ 1000/Cl in the formation water are higher than the value of 0.8575 and lower than 1.5363 in the sea water, respectively, which might be attributed to halite dissolution.     

Isotope Geochemistry of the Xinchang -Yongjia Silver (Lead-Zinc)Ore Belt in Eastern Zhejiang Province

In the Xinchang-Yongjia silver (lead-zinc) ore belt, there mainly occur the large to medium-sized Haoshi, Bamao, Dalingkou and Wubu silver deposits or silver-bearing lead-zinc deposits. On the basis of researches on these typical deposits, the mechanism of leaching-drawing mineralization of Mesozoic geothermal water and the related model are put forward in this paper in the light of the time interval between rock and formation ages as well as hydrogen, oxygen, sulphur and lead isotope geochemical characteristics. The major metallogenic process occurred in volcanic rock layers. The ore-forming fluids are geothermal water coming from meteoric water and circulating at shallow layers. This geothermal water leached and absorbed ore-forming materials from its country rocks during its flowing (such metallogenic elements as silver, lead-zinc and sulphur mainly came from consolidated volcanic rocks), leading to the formation of meso - epithermal silver deposits.     

Biogeochemical Model and Simulation of the Effect of Precambrian Algae on the Formation Process of Certain Laminated Cherts

The source of silica in the formation of the Precambrian laminated cherts has long remained a problem to be solved. Through experiments on cherts and living blue-green algae, the authors found that the collected chert samples probably come from primary deposits, and there is a great biomass of fossil algae in chert, among which the filamentous algae can be compared with the living blue-green algae Oscillatoria, that a higher Pco_2 of the gas would be favourable for the increase of the biomass of living blue-green algae and consequently raises the pH value of the water body; and that lack of free oxygen and a higher concentration of SiO_2 in the water have no apparent influence on the biomass of blue-green algae. Based on the evidence above, a biogeochemical model concerning the origin of Precambrian laminated chert has been set up, in which the. photosynthesis of algae under the presumed atmospheric conditions of the Precambrian might raise the pH value of the water body and promote the dissolution of silicate minerals, thus providing a source of colloid SiO_2 for the formation of Precambrian laminated chert.Furthermore, a simulation experiment device has been designed successfully, which can control the temperature(30 ± 0.5°), Pco_2(50662.5 Pa) and Po_2(about zero Pa) of the gas, the rate of photosynthesis of algae and the movement of the water carrying opal. In the simulation experiments, separate measurements have been made on the rate of photosynthesis of algae, pH value and concentration of SiO_2 of the water body, with the results indicating that under the conditions similar to the presumed Precambrian atmosphere, the photosynthesis of algae can make the pH value of the water body go up steadily to over 9.7, leading to the dissolution of the silicate minerals, with the concentration of SiO_2 measured reaching as high as 84 mg/l. Finally, through the vaporation of water, a phenomenon of colloid floccilation has been observed.The simulation experiment has verified the proposed biogeochemical model illustrating the origin of Precambrian laminated chert. Moreover, the device and method of its kind may also be applied to the research on the relationship of the Precambrian algae with the formation of some other mineral deposits such as of Fe, Mn, U and carbonates.     

Rheological Simulating Study of Mechanical Conditions for Syn-extensional Basin and Mountain Coupling System

This article gives a mechanical model, in which the layers of lithosphere are assumed to be the creep materials, to study the coupling mechanism of a syn-basin-mountain system quantitatively by using the numerical simulating method. A geological dynamic extensional mode given by some geologists is theoretically discussed and verified. The study shows that lithosphere thickening or thinning is closely related to the thermal activity, or in other words, thermal convection beneath the lithosphere. It is one of the important factors affecting the formation of the basin-mountain coupling system. As an essential condition, only the upward buoyant force and the horizontal dragging force caused by the thermal convection jointly act on the bottom of the lithosphere, the stress and strain states in rock‘‘s layers are advantageous to forming the tectonic-landforms of the basin-mountain coupling system. A study on the creep features of the lithosphere shows that the stress and strain in the rock‘‘s layers vary with time when the lasting forces act on the boandary. They increase rapidly at initial stage and decrease steadily after reaching the peak value. Phenomena of stress relaxation are significant for studying the tectonic evolution.     

Experimental Study on Formation Conditions of Ammoniojarosite and Its Environmental Significance

Formation conditions of ammoniojarosite in system Fe2（SO4）3-（NH4）2SO4-H2O are investigated in this paper. The results show that ammoniojarosite can be formed rapidly under normal temperature and pressure by controlling suitable pH value and Fe2（SO4）3 and （NH4）2SO4 concentrations. The pH value, temperature and concentration of Fe2（SO4）3 medium are key factors influencing the formation of ammoniojarosite. Under normal temperature, precipitation of ammoniojarosite can be seen within 24 hours at pH values between 2.6-3.1, and a great quantity of ammoniojarosite is formed within 48 hours. At about 90℃, the pH value range forming ammoniojarosite extends to 1.2-3.1, and within this range the rise of pH value is advantageous to the formation of ammoniojarosite and high Fe2（SO4）3 concentration is also advantageous. Relative pure ammoniojarosite is synthesized under high Fe2（SO4）3 concentration （≥0.05 M） and ammoniojarosite containing melanterite and colloid amorphous hydroxide vitriol iron is formed at low Fe2（SO4）3 concentration. The deposition process of ammoniojarosite can be used to harness wastewater from mines and other industries and remove S, Fe and other toxic and harmful elements, such as As, Cr, Hg, Pb in water. Rapid formation of ammoniojarosite and other jarosite analogs under normal temperature and pressure has a good potential prospect for harnessing acid wastewater by means of precipitation of jarosite and its analogs.     

我国陆相盆地油田水文地球化学特征

From the viewpoint of geological development, the mechanisms of formation of oil-field waters in non-marine basins and their relation with oil-gas reservoirs are discussed briefly. Sedimentary basins differing in geological setting and physical geographical environment would lead to a diverse evolution of fossil lake basin water body in chemical composition in the process of formation, development and extinction by themselves, resulting in oil-field waters with complex; variable and characteristic compositious China‘s non-marine basins are mostly derived from fossil lake basins. The substantial petroleum-generating stage is highly expected during the development of these fossil lake basins. The production of hydrocarbons responsible for petroleum is always accompanied by the production of sedimentary water. As a result, oil-gas migration took place under the action of high-pressure water and led to the preferential accumulation in the surrounding geological structures as a girdle pattern. In the oil-gas-bearing basins where seeping water is abundant, oil-gas reservoir are found distributed mainly along the “intersection zone” -- the “erestal plane”between the “ fossil-dewatering” of sedimentary water and the “fossil-interpolation”of seeping water. Due to the influence of various factors and the geochemical reactions, oilfield waters in Chiua‘s non-marine basins have remarkable “ion differential” phenomenon. Based on the phenomenon four types of ion assemblages can be distinguished.     

The Early Permian Woniusi Flood Basalts from the Baoshan Terrane, SW China: Petrogenesis and Geodynamic Implications

The Woniusi flood basalts from the Baoshan terrane, SW China, represent a signi?cant eruption of volcanic rocks which were linked to the Late Paleozoic rifting of the Cimmeria from the northern margin of East Gondwana. However, the precise mechanism for the formation and propagation of the rifting is still in debate. Here we report 40Ar/39Ar dating, whole-rock geochemistry, and Sr–Nd–Pb isotopes for the Woniusi basalts from the Baoshan terrane of SW China, with the aim of assessing if a mantle plume was related to the formation of the continent Cimmeria. 40Ar/39Ar dating of the Woniusi basalts yielded ages of 279.3 ± 1.1 Ma and 273.9 ± 1.5 Ma, indicating they were emplaced during the Early Permian. Whole-rock geochemistry shows that these basalts have subalkaline tholeiitic af?nity, low TiO2 (1.2–2.2 wt%), and fractionated chondrite-normalized LREE and nearly ?at HREE patterns [(La/Yb)N = 2.86–5.77; (Dy/Yb)N = 1.21–1.49] with noticeable negative Nb and Ta anomalies on the primitive mantle-normalized trace element diagram. The ?Nd(t) values (?4.76 to +0.92) and high (206Pb/204Pb)i (18.40?18.66) along with partial melt modeling indicates that the basalts were likely derived from a sub-continental lithospheric mantle (SCLM) source metasomatized by subduction-related processes. On the basis of a similar emplacement age to the Panjal basalts and Qiangtang mafic dykes and flood basalts in the Himalayas, combined with a tectonic reconstruction of Gondwana in the Early Permian, we propose that the large-scale eruption of these basalts and dykes was related to an Early Permian mantle plume that possibly initiated the rifting on the northern margin of East Gondwana.     

Geology and mineralization of the Tiegelongnan supergiant porphyry-epithermal Cu (Au,Ag) deposit (10 Mt) in western Tibet,China: A review

The Tiegelongnan Cu(Au,Ag)deposit in central Tibet contains more than 10 Mt of copper ranking 29 th in the world.It is characterized by typical porphyry-epithermal alteration and mineralization.In order to improve the understanding of porphyry-epithermal copper deposit in Tibet,new zircon U-Pb age and sulfur isotope data along with published data in the Tiegelongnan are presented to investigate the formation and preservation mechanism.Ore-related intrusive rocks in the Tiegelongnan including Early Cretaceous(about 120 Ma)granodiorite porphyry and diorite porphyry are closely related to the northward subduction of Bangongco-Nujiang ocean.Sulfur mainly comes from deep magma,and ore-forming fluid is affected by both magmatic and meteoric water.The metallogenic setting of Tiegelongnan is consistent with those of Andean porphyry copper deposits in South America.The cover of the Meiriqiecuo Formation volcanic rocks,Lhasa-Qiangtang collision and India-Eurasian collision have significance in the preservation and uplift of the deposit.The formation,preservation and discovery of Tiegelongnan play an important role in exploration of ancient porphyry-epithermal deposits in Tibet.     

Physico-chemical Conditions and Ore-forming Process of the Zhilingtou Au-Ag Deposit, Zhejiang

The mineralization of the Zhilingtou Au-Ag deposit occurred in a heated circulation system of infiltratedmeteoric water during the Indosinian and early Yanshanian, at a temperature ranging from 350 to 160℃ andat a depth of less than 2 km. The ore-forming solution was acidic, strongly oxidized. and poor in sulfur, withmoderate Cl~- activity and salinity. Au and Ag migrated in the forms of AuCl_2~- and AgCl_2~-, and then wereconcentrated and precipitated in a pressure-relief, dilatant zone-a tenso-shear fracture. Pressure relief and boiling were the major mechanism for unloading of the fluid. The hydrothermal fluidwas injected intermittently, and its boiling was characterized by pulsation. The presence of high-valence man-ganese might represent the auxiliary mechanism for remobilization of Au and Ag in the Chencai Group and fortheir entering into the hydrothermal fluid.     

Geochemical and Geochronological Constraints on the Origin of the Meta-basic Volcanic Rocks in the Tengtiaohe Zone,Southeast Yunnan

The meta-basic volcanic rocks in the Tengtiaohe Zone yield zircon U–Pb ages of 258.8±2.5 Ma and 259.2±1.8 Ma, respectively which agree with the ages of flood basalts of ELIP and are similar to the basaltic rocks and komatiites from the Song Da Zone in northern Vietnam. The results suggest that the age of meta-basic volcanic rocks is Late Permian, rather than the Early Permian or Early Carboniferous ages as previously inferred. Most meta-basic volcanic rocks are strongly enriched in LREEs relative to HREEs and display trace element patterns similar to the ELIP high-Ti basalts, and are enriched in LILEs with negative Sr anomalies. Their initial ~(87)Sr/~(86) Sr ratios range from 0.705974 to 0.706188 and εNd(t) from-0.82 to-2.11. Their magmas were derived from an enriched and deep mantle source without significant crustal contamination. These meta-basic volcanic rocks formed in ELIP. Therefore, the Tengtiaohe Zone is not an ophiolite zone and can link to the Song Da Zone in northern Vietnam.     

Pyrite Surface after Thiobacillus ferrooxidans Leaching at 30℃

In order to investigate the effect of Thiobacillus ferrooxidans on the oxidation of pyrite, two parallel experiments, which employed H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans, were designed and carried out at 30℃. The initial pH of the two solutions was adjusted to 2.5 by dropwise addition of concentrated sulphuric acid. The surfaces of pyrite before exposure to leaching solutions and after exposure to the H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans were observed by scanning electron microscopy (SEM). There were a variety of erosion patterns by Thiobacillus ferrooxidans on the bio-leached pyrite surfaces. A conclusion can be drawn that the oxidation of pyrite might have been caused by erosion of the surfaces. Attachment of the bacteria to pyrite surfaces resulted in erosion pits, leading to the oxidation of pyrite. It is possible that the direct mechanism plays the most important role in the oxidation of pyrite. The changes in iron ion concentrations of both the experimental solutions with time suggest that Thiobacillus ferrooxidans can enhance greatly the oxidation of pyrite.     

Pyrite Surface after ThiobaciUusferrooxidans Leaching at 30℃

In order to investigate the effect of Thiobacillusferrooxidans on the oxidation of pyrite, two parallel experiments, which employed H2SO4 solutions and acidic solutions inoculated with ThiobaciUus ferrooxidans, were designed and carried out at 30℃. The initial pH of the two solutions was adjusted to 2.5 by dropwise addition of concentrated sulphuric acid. The surfaces of pyrite before exposure to leaching solutions and after exposure to the H2SO4 solutions and acidic solutions inoculated with Thiobacillus ferrooxidans were observed by scanning electron microscopy （SEM）. There were a variety of erosion patterns by Thiobacillusferrooxidans on the bio-leached pyrite surfaces. A conclusion can be drawn that the oxidation of pyrite might have been caused by erosion of the surfaces. Attachment of the bacteria to pyrite surfaces resulted in erosion pits, leading to the oxidation of pyrite. It is possible that the direct mechanism plays the most important role in the oxidation of pyrite. The changes in iron ion concentrations of both the experimental solutions with time suggest that ThiobaciUus ferrooxidans can enhance greatly the oxidation of pyrite.     

Quartz Cement in Middle Jurassic Reservoir Sandstones in North Sea A Review. Part II： Duration and Silica Sources

The timing and duration of quartz cementation in sandstones have been mainly inferred from diagenetic texture, relationship between pore filling minerals, fluid inclusions and isotopic data. Fluid inclusion temperatures from North Sea reservoir sandstones indicate that most of the quartz cement forms at temperature exceeding 90℃ and is continually proceeding after oil emplacement, based on the fluid inclusion temperatures in quartz overgrowth which is approaching the bottom-hole temperatures. The duration of quartz cement after oil emplacement depends upon the saturation of porewater and the distribution of pore water film and the property of water-wet or oil-wet of the reactants. The leaching of K-feldspar by meteoric water requires pore water flow to move the released potassium and sodium and silica out the solution, which suggests the mechanism does not appear to be a major source of silica for quartz cementation. The quartz cementation coincidence with the compaction and pressure solution suggests the major source of silica. The alteration of feldspar by illitization of kaolinite may serve as another important source of silica at deep burial depth. External sources are not need to call on for illustrating the quartz cementation, because there is no evidences for large scale convection of pore water flow occurred in the burial history of reservoir sandstones of middle Jurassic in the North Sea.     

Aqueous geochemistry of rare-earth elements in karst lakes, southwestern China

Due to the unique chemical properties that are similar but still progressively change, the rare earth elements （REEs） are useful tracers of various geochemical processes in the lithosphere and hydrosphere. However, despite many studies of REE geochemistry in the ocean, the aqueous geochemistry of REEs in lake waters has been poorly documented. In the present study, two special karst lakes are chosen as case studies to investigate the distributions of dissolved REEs in lake water. Although the two lakes, Hongfeng and Aha, are both alkaline and have high pH from 7.9 to 8.7 and high carbonate concentrations, the Aha Lake has been more severely affected by acidic mining drainage with high Fe, Mn and SO42 concentrations. In the present study, the concentrations of dissolved rare-earth elements in lake waters were determined by inductively coupled plasma mass spectrometry. The result shows that the concentrations of dissolved REEs in the studied alkaline karst lakes, as compared to the concentrations of REEs in seawater, are much lower than the other investigated terrestrial surface waters in previous studies. The key factor controlling dissolved REE distributions is pH value which is negatively correlated with REE concentrations. Due to high concentration of carbonate ion and alkaline character of water chemistry, the shale （PAAS） normalized patterns of dissolved REEs show marked HREE enrichment in all water samples. This is primarily the result of the preferential formation of stronger carbonate complexes with the HREEs. In alkaline or intermediate waters, REE-carbonate complexes are the dominant and typical species, which account for about more than 90% of the total dissolved REEs.     

Nitrogen Removal in Wastewater Irrigation Systems and Its Influence on Groundwater Pollution

The experiment included ten soil columns and field investigation in 1-2 year duration. Data on the columns continuously flooded with waste water indicated that when total input of NH_4-N reached to above 70％ of the NH_4-N adsorption capacity in soil the breakthrough would appear in the output . Adequate removal of nitrogen from the waste water would require at least 170 cm deep groundwater table . Fine textured soil would promote denitrification . The columns simulating discontinuous waste water irrigation indicated that denitrification existed only in the partial microenviroument of reduction . Groundwater table depth had no strong influence on nitrogen removal . The investigation in field revealed that the groundwater recharged with waste water was not polluted by nitrogen when the aeration profile was in finer textures owing to the combined contribution of nitrification and denitrification.