Microbial Community with Potential for Metal Release Isolated from Palca Mine Tailings Pond in Peru

The improvement of microbial characterization has increased the comprehension of microbial population and their ability in the microbiological metal dissolution. Bioleaching processes have been expanded to use microorganisms for the recovery of metals from ores and wastes. This study introduces Palca mine tailings pond in Peru which turned into acid mine drainage (AMD). AMD is a source of microbial communities whose microorganisms may support the aqueous extractive metallurgy for metal recovery. Four samples of AMD were collected from different locations and the elemental characterization showed concentrations of metals, such as Cu, Zn, Al, Mn, and Fe. The pH of the samples showed variation between 1.9 - 6.8. Twenty-one microorganisms were isolated and selected according the cell morphology. 16s rRNA gene sequences identified five species of which three belong to the bacterial kingdom and two to the Fungi kingdom. Two of the bacterial species were ferrous ion oxidizing bacteria, identified as Acidithiobacillus ferriphilus and Acidithiobacillus ferridurans;and the other one a ferric ion reducing bacteria identified as Acidiphilium acidophilum. The fungi species identified were Rhodotorula sinensis and Exophiala xenobiotica, a filamentous fungus isolated for the first time from an AMD.

Assessing the impact of artificial recharge on groundwater in an overexploited aquifer: A case study in the Cheria Basin, North-East of Algeria

The Cheria region in Northeastern Algeria has been facing aquifer overexploitation by the agricultural sector and prolonged droughts,resulting in a considerable decline in groundwater levels.This study investigates the feasibility of implementing artificial recharge techniques to replenish the Eocene aquifer which serves as the primary water source in the Cheria region.A 3D transient numerical model,based on the finite difference method,was used to simulate groundwater flow from 2021 to 2031 using Visual MODFLOW Flex.During the modelling process,three scenarios were considered:(1)including pumping without a recharge,(2)recharge of the entire area through efficient infiltration without pumping,and(3)artificial recharge using river water infiltration basins at two sites,Draa Douamis sinkholes and Eocene limestone outcrops.The simulation results showed that aquifer exploitation without recharge caused significant drawdowns,which were 3 m to 7 m in the north-eastern part and 8 m to 12 m in the central and southern parts.In contrast,the second scenario,involving recharge without pumping,showed a rise in groundwater levels of 2 m to 2.7 m in the north-eastern part and 3 m to 3.62 m in the central and southern parts.The third scenario,employing artificial recharge,indicated a positive response to artificial recharge,with increased piezometric levels at the proposed sites,signifying a beneficial impact on the aquifer.These findings underline the potential of artificial recharge as a promising approach to address the groundwater depletion and environmental issues in the Cheria Basin.

Petrologic perspectives on tectonic evolution of a nascent basin(Okinawa Trough) behind Ryukyu Arc: A review

Okinawa Trough is a back-arc, initial marginal sea basin, located behind the Ryukyu Arc-Trench System. The formation and evolution of the Okinawa Trough is intimately related to the subduction process of the Philippine Sea Plate beneath the Eurasian Plate since the late Miocene. The tectonic evolution of the trough is similar to other active back-arcs, such as the Mariana Trough and southern Lau Basin, all of which are experiencing the initial rifting and subsequent spreading process. This study reviews all petrologic and geochemical data of mafic volcanic lavas from the Okinawa Trough, Ryukyu Arc, and Philippine Sea Plate, combined with geophysical data to indicate the relationship between the subduction sources （input） and arc or back-arc magmas （output） in the Philippine Sea Plate-Ryukyu Arc-Okinawa Trough system （PROS）. The results obtained showed that several components were variably involved in the petrogenesis of the Oki-nawa Trough lavas：sub-continental lithospheric mantle underlying the Eurasian Plate, Indian mid-oceanic ridge basalt （MORB）-type mantle, and Pacific MORB-type mantle. The addition of shallow aqueous fluids and deep hydrous melts from subducted components with the characteristics of Indian MORB-type mantle into the mantle source of lavas variably modifies the primitive mantle wedge beneath the Ryukyu and sub-continental lithospheric mantle （SCLM） beneath the Okinawa Trough. In the northeastern end of the trough and arc, instead of Indian MORB-type mantle, Pacific MORB-type mantle dominates the magma source. Along the strike of the Ryukyu Arc and Okinawa Trough, the systematic variations in trace element ratios and isotopic compositions reflect the first-order effect of variable subduction input on the magma source. In general, petrologic data, combined with geophysical data, imply that the Okinawa Trough is experiencing the＂seafloor spreading＂process in the southwest segment,＂rift propagation＂process in the middle seg-ment, and＂crustal extension＂process in the northeast segment, and a nascent ocean basin occurs in the southwest segment.

Geological comparative studies of Japan Arc System and Kyushu-Palau Arc

Based on the published data of structure geology,geochronology,petrology and isotope geochemistry,the authors of this paper have conducted studies on the tectonic evolution history of Japan arc system and Kyushu-Palau ridge（KPR） . The studies show that the initial Japan arc system was resulted from the subduction of ancient Pacific plate beneath Eurasian Plate in Permian. It was part of an Andean-type continental volcanic arc which occurred in the offshore in the east of Asian during late Mesozoic era. The formation of tertiary back-arc basin（Japan Sea） resulted in the fundamental tectonic framework of the present arc system. Since Quaternary the system has been lying at E-W compression tectonic setting due to the eastward subduction of Amur Plate. It is expected that Japan arc system will be juxtaposed with Asian continent,which is similar to the present Taiwan arc system. The origin of Philippine Sea Plate（PSP） is still in debate. Some studies argued that it is a trapped oceanic crust segment,while the others insisted that it is a back-arc basin accompanied with ancient IBM arc. However,it is all agreed that the tectonic evolution of PSP started since 50 Ma,i.e.,PSP has drifted from the site around equator at 50 Ma to the present site,and the subduction of PSP along Nankai trough-Ryukyu Trench beneath the Japan arc system during 6–2 Ma led to the formation of the present Ryukyu arc system. Of the PSP,the KPR has been found with the oldest rocks formed at 38 Ma. Combining with its geochemical characteristics of oceanic arc tholeiite,it is suggested that KPR is an intraoceanic volcanic arc,more specifically,a relic arc（i.e.,rear arc of the ancient IBM） after rifting of ancient IBM. In addition,Amami-Daito province is of arc tectonic affinity,but has been affected by mantle plume. Therefore,based on their respective tectonic evolution history and geochemical characteristics of rock samples,it is inferred that there is no genetic relationship between Japan arc system and KPR. It is noted that rocks reflecting continental crust basement feature have been collected on the northern tip of KPR,which may be related to the process of KPR accreting on Japan arc,but the arc-continent accretion process are still at initial stage of modern continental crust accretion model. However,due to the scarcity of data of the northern tip of KPR,crustal structure of this location and its adjacent Nankai trough need to be further constrained by geophysical studies in the future.

Potassium-argon/argon-40-argon-39 geochronology of Cenozoic alkali basalts from the South China Sea

Based on the isotopic chronologic results of Cenozoic alkali basalts from the South China Sea, the characteristics of volcanic activi- ty of the South China Sea after spreading were studied. The potassium - argon ages of eight alkali basalt samples from the South China Sea, and the argon - argon ages of two samples among them are reported. Apparent ages of the whole rock are 3.80 to 7. 91 Ma with an average value of 5.43 Ma （potassium- argon, whole rock）, and there is little difference among samples at the same location, e. g. , 4. 76 - 5.78 Ma for location S（M-12. The argon - argon ages for the two samples are 6.06 and 4. 71 Ma, which lie within the age scope of potassium - argon method. The dating results indicate that rock-forming age is from late Miocene to Pliocene, which is consistent with erupting event for alkali basalts from adjacent regions of the South China Sea. Volcanic activities occur after the cessation of spreading of the South China Sea, which are controlled by lithospheric fault and the spreading center formed during the spreading period of the South China Sea. These dating results, combined with geochemical characteristics of these basalts, the published chronological data for the South China Sea and its adjacent regions, and the updated geophysical data near Hainan Island, suggest that after the cessation of spreading of the South China Sea, there occur widely distributing magmatic activities which primarily is alkali basalt, and the volcanic activity continues to Quaternary. The activity may be relative to Hainan mantle plume originated from core/mantle boundary.

REE and Trace Element Geochemistry of Yinachang Fe-Cu-REE Deposit, Yunnan Province, China

REE and other trace elements in ores, wall rocks, alkaline volcanic rocks and diabase dikes have been determined in the Yinachang Fe-Cu-REE deposit. Comparative studies of REE and trace element geochemical characteristics of these geological bodies indicate that the ores and alkaline volcanic rocks contain abundant REE and Y ({65.9}-{4633})×10+{-6}, with higher abundances of As, Mo, Nb, Co and U than those of the crust. Their chondrite-normalized patterns show a strong enrichment of LREE and a positive Eu anomaly, in contrast to those of the dolomites which are characterized by slight LREE enrichment and moderate negative Eu anomaly. The REE patterns of ores are similar to those of hydrothermal sediment cores in the East Pacific Rise, whereas the REE patterns of dolomites are similar to those of PAAS (Post-Archean Average Shale). In combination with the geological setting of the deposit, the primary ore-forming fluids might have higher REE and volatile elements, and might have been derived from mantle degassing, or the alkaline volcanic magmas. The Yinachang Fe-Cu-REE ore deposit is considered to be of volcanic exhalation-hydrothermal sedimentary origin.

The determination of 52 elements in marine geological samples by an inductively coupled plasma optical emission spectrometry and an inductively coupled plasma mass spectrometry with a high-pressure closed digestion method

An improved analytical method to determine the content of 52 major, minor and trace elements in marine geological samples, using a HF-HCl-HNO_3 acid system with a high-pressure closed digestion method（HPCD）, is studied by an inductively coupled plasma optical emission spectrometry（ICP-OES） and an inductively coupled plasma mass spectrometry（ICP-MS）. The operating parameters of the instruments are optimized, and the optimal analytical parameters are determined. The influences of optical spectrum and mass spectrum interferences, digestion methods and acid systems on the analytical results are investigated. The optimal spectral lines and isotopes are chosen, and internal standard element of rhodium is selected to compensate for matrix effects and analytical signals drifting. Compared with the methods of an electric heating plate digestion and a microwave digestion, a high-pressure closed digestion method is optimized with less acid, complete digestion,less damage for digestion process. The marine geological samples are dissolved completely by a HF-HCl-HNO_3 system, the relative error（RE） for the analytical results are all less than 6.0%. The method detection limits are 2–40μg/g by the ICP-OES, and 6–80 ng/g by ICP-MS. The methods are used to determine the marine sediment reference materials（GBW07309, GBW07311, GBW07313）, rock reference materials（GBW07103, GBW07104,GBW07105）, and cobalt-rich crust reference materials（GBW07337, GBW07338, GBW07339）, the obtained analytical results are in agreement with the certified values, and both of the relative standard deviation（RSD） and the relative error（RE） are less than 6.0%. The analytical method meets the requirements for determining 52 elements contents of bulk marine geological samples.

Industrial Potentiality of Alluvial Clays Deposits from Cameroon: Influence of Lateritic Clayey Admixture for Fired Bricks Production

The cartography and characterization of an alluvial clay deposit from Ebebda (Central region of Cameroon) were carried out in order to assess its suitability for the production of fired clay bricks. The clayey area investigated is ~ 50,000 m2 with an average thickness of the exploitable layer of 2.2 m, suggesting a deposit of about ~2.2 × 105 tonnes of clay. Mineralogy, physico-chemical and thermal analyses as well as firing properties were performed on representative clay samples. Kaolinite and quartz are the major minerals associated to illite. Upon heating to 900℃ - 1200℃, the linear shrinkage varies from 1.5% to 15%, the water absorption from 1.5% to 24% and the bending strength from 2 to 12 MPa. The admixture of lateritic clays (widely available) at 50%, 60%, 70% and 80% allow to decrease the shrinkage and bending strength, and to increase the water absorption. Overall, properties were satisfying the requirement for fired brick with 70% of laterite in the mixture.

Suitability of Foumban Clays (West Cameroon) for Production of Bricks and Tiles

Particle size analysis, Atterberg limits, X-ray diffraction, X-ray fluorescence and firing tests were used to determine physico-chemical, mineralogical and technological characteristics of residual lateritic (K1M, Ma2) and alluvial (KB3, KG3) clays from Foumban (West-Cameroon). For technological properties, the samples were pressed and fired over a temperature range of 900&degC - 1200&degC to determine the open porosity, linear shrinkage, bulk density and compressive strength. Kaolinite (31% - 65%) and quartz (35% - 50%) are dominant in Foumban clays with accessory K-feldspar, plagioclase, illite, smectite, rutile, and goethite. But their proportion changes from one sample to another, having a significant effect on the behaviour of the clay materials: highest proportion of quartz (50%) in sample K1M;relative high feldspars (20%) and illite contents (10%) in KB3 and MA2;high smectite content in KG3 (up to 20%). Chemical analyses indicate high SiO2 (49% - 77%) and low Al2O3 (14% - 23%) contents in the four samples, with comparatively low contents of iron oxides (4% - 7% in samples KB3 and KG3, 2.5% in MA2 and ~1.5% in sample K1M). The particle size distribution of the alluvial clays (KG3 and KB3) differs considerably: 7% to 37% of clay fraction, 20% to 78% of silt, and 15% to 58% of sand, while residual clays (K1M and MA2) present on average 12% of clay, 51% of silt and 37% of sand. Two raw clays (KB3 and MA2) can be used for bricks/tiles production without beneficiation or addition. K1M requires some flux addition to decrease the sintering temperature while KG3 presents poor properties due to the combined occurrence of smectite and a high clayey fraction (37%). Such mineralogical composition is responsible for very high plasticity (PI: 50), high shrinkage (LS: 5% - 16%), low porosity (OP: up to 21%) and high flexural strength (FS: 16 - 23 N/mm2) above 1050&degC. This last clay is therefore less appropriate for bricks and roofing tiles production since degreasers must be added to the raw material.

An origin of the along-arc compositional variation in the Izu-Bonin arc system

The Izu-Bonin arc system is sediment-poor(~400 m thick with no accretionary prism)and,therefore,the influence of the altered oceanic crust(AOC)is most likely the source of the documented along-arc lava compositional variations,especially in Pb isotopes.Izu-Bonin arc lava geochemistry suggests an influx of subduction component from an Indian-type AOC.However,samples drilled from the western Pacific geochemical reference site at Integrated Ocean Drilling Program Site 1149 implies subduction of a Pacific-type AOC.To solve the apparent discrepancy of slab input versus arc output in this arc system,samples of the AOC were dredged from vertical fault scarps of the subducting Pacific Plate along a transect from 27.5°N to 34.50 N.Samples range from tholeiitic to mildly alkalic mid-ocean ridge basalts as well as trachybasalts,basaltic trachyandesites,tephrites,and phono-tephrites.Isotope ratios also exhibit a range of values(87Sr/86Sr=0.70282-0.70673,143 Nd/144 Nd=0.512552-0.513174,206Pb/204 Pb=18.43-20.00,207 Pb/204 Pb=15.40-15.67,208Pb/204Pb=37.75-39.55).Our results suggest that there is a geochemical variation in the AOC that is neither completely due to seawater or hydrothermal alteration,nor to petrogenetic processes.Rather,this variation is the result of the Pacific-Izanagi Ridge system tapping into a heterogeneous,plume-polluted mantle source during the Mid-Cretaceous volcanic event.The observed Pacific-type AOC is not responsible for the Indian-type Pb isotopic signature of Izu-Bonin arc lavas.This leads us to propose an alternative scenario where the Izu-Bonin arc lava Indian-type Pb isotopic signature originates from slab-derived fluids interacting and adsorbing Pb from an Indian-type mantle wedge through zone-refining.

Preliminary K-Ar geochronology of lavas from southern Lau Basin

In this short note, we report the ages of five lava samples from a segment of the Eastern Lau Spreading Center （ELSC） and three samples from the Valu Fa Ridge （VFR） in the southern Lau Basin. These samples were collected in situ from the axes and flanks of the spreading centers in the basin. These ages provide a key to better understanding the spreading mode, crustal formation and overall tectonic evolution of the basin. Except for two basaltic andesites and one andesite, the lavas analyzed are basalts. The ages of the lavas from ELSC range from （1.45±0.15） Ma to （0.74±0.04） Ma whereas those from VFR range from （0.50±0.06） Ma to （0.32±0.27） Ma, and the basalts give the oldest ages. The relatively younger ages of the VFR lavas are consistent with proposed tectonic evolution of the southern Lau Basin, i.e., VFR is a propagating extension of ELSC. The occurence of older lavas close to or on spreading axes in the southern Lau Basin implies the complex tectonic evolution of the basin. These results underscore a need for further detailed geophysical and geological studies in the southern Lau Basin, in order to better clarify the crustal accretion tectonic evolution in this area.

Aptian–Albian Transition in Central Tunisia:Tectonosedimentary and Paleogeographic Records

The Aptian-Albian series are characterized, in Tunisia, by several variations in subsidence rates and records discrete unconformity between Albian and Aptian in central and southern Tunisia. In central Tunisia Upper Aptian regressions were sustained until the beginning of Albian with a low sea level stand. In this paper, wells data gathered from central Tunisia exposes well expressed Aptian-Albian hiatus associated to several partial sedimentary gaps, erosion surface and unconformities and correlated with the ＂Aptian Crisis＂ highlighted at the Tethyan scale. This latter is coeval with an extensional regime in concurrence with the African rifting responsible for halokinesis movements and magmatism and leaded to the establishment of paleoreliefs as much as tilted blocks and half grabens in central Tunisia. Deposition shows regional hiatus and lateral transition from platform facies to south to, open marine facies to the north. The structural configuration of this domain within normal faulting, horsts and grabens leaded to the establishment of several distinct basins with different subsidence rates. Discordances occur specially around and upward uplifted blocks and emerged land and are especially associated with Aptian reef, karsts and shallow marine facies. They are unconformably overlaid by the transgressive open marine facies of Albian-Cenomanian series acknowledged as source rock in Central Tunisia. In addition, the reefal Aptian facies is considered a potential reservoir rocks in central Tunisia and it is frequently associated to mineralization and Hydrocarbure reservoirs.

Major element,trace element,and Sr,Nd and Pb iso-tope studies of Cenozoic basalts from the South China Sea

The whole rock K-Ar ages of basalts from the South China Sea basin vary from 3.8 to 7.9 Ma, which suggest that intra-plate volcanism after the cessation of spreading of the South China Sea (SCS) is comparable to that in adjacent regions around the SCS, i.e., Leiqiong Peninsula, northern margin of the SCS, Indochina block, and so on. Based on detailed petrographic studies, we selected many fresh ba-saltic rocks and measured their major element, trace element, and Sr-Nd-Pb isotope compositions. Geochemical characteristics of major element and trace element show that these basaltic rocks belong to alkali basalt magma series, and are similar to OIB-type basalt. The extent of partial melting of mantle rock in source region is very low, and magma may experience crystallization differentiation and cu-mulation during the ascent to or storing in the high-level magma chamber. Sr-Nd-Pb isotopic data of these basaltic rocks imply an inhomogeneous mantle below the South China Sea. The nature of magma origin has a two end-member mixing model, one is EM2 (Enriched Mantle 2) which may be originated from mantle plume, the other is DMM (Depleted MORB Mantle). Pb isotopic characteristics show the Dupal anomaly in the South China Sea, and combined with newly found Dupal anomaly at Gakkel ridge in Arctic Ocean, this implies that Dupal anomaly is not only limited to South Hemisphere. In variation diagrams among Sr, Nd and Pb, the origin nature of mantle below the SCS is similar to those below Leiqiong peninsula, northern margin of the SCS and Indochina peninsula, and is different from those below north and northeast China. This study provides geochemical constraints on Hainan mantle plume.

Accumulation and Output of Heavy Metals by the Invasive Plant Spartina alterniflora in a Coastal Salt Marsh

Spartina alterniflora is a foreign introduced species and has far-reaching effects on salt marsh ecosystems, particularly on the biogeochemical cycle of heavy metals. To ascertain whether the invasive plant Spartina alterniflora Loisel is a source of metals in the environment, we determined the bimonthly concentrations of heavy metals, chromium(Cr), lead(Pb), copper(Cu), zinc(Zn),and manganese(Mn), in the roots, stems, and leaves of S. alterniflora from a typical semidiurnal tidal zone in the coastal area of northern Jiangsu Province, China. Based on the measurements, we calculated annual metal primary accumulation and output. To calculate the annual output of heavy metals from S. alterniflora, a new method that calculates the annual rate of biomass loss and decomposition was developed. The annual primary accumulation of Cr, Pb, Cu, Zn, and Mn was 19.08, 84.19, 63.74, 442.58, and774.66 mg m^(-2), respectively, and the annual output from S. alterniflora to the surrounding environment was 4.01, 18.09, 14.00, 97.11,and 164.28 mg m^(-2), respectively. Spartina alterniflora only provides temporary storage, and its absorption of heavy metals could be used to remediate contaminated soil and for phytomining. The heavy metals released by S. alterniflora to the environment cannot be ignored; thus, S. alterniflora should be considered a source of metal contamination. Therefore, when we evaluate the remarkable ability of certain plant species to concentrate metals in their tissues, the balance between heavy metal accumulation and output should be considered.