Classification and mineralization of global lithium deposits and lithium extraction technologies for exogenetic lithium deposits

A reasonable classification of deposits holds great significance for identifying prospecting targets and deploying exploration. The world ’s keen demand for lithium resources has expedited the discovery of numerous novel lithium resources. Given the presence of varied classification criteria for lithium resources presently, this study further ascertained and classified the lithium resources according to their occurrence modes, obtaining 10 types and 5 subtypes of lithium deposits(resources) based on endogenetic and exogenetic factors. As indicated by surveys of Cenozoic exogenetic lithium deposits in China and abroad,the formation and distribution of the deposits are primarily determined by plate collision zones, their primary material sources are linked to the anatectic magmas in the deep oceanic crust, and they were formed primarily during the Miocene and Late Paleogene. The researchers ascertained that these deposits,especially those of the salt lake, geothermal, and volcanic deposit types, are formed by unique slightly acidic magmas, tend to migrate and accumulate toward low-lying areas, and display supernormal enrichment. However, the material sources of lithium deposits(resources) of the Neopaleozoic clay subtype and the deep brine type are yet to be further identified. Given the various types and complex origins of lithium deposits(resources), which were formed due to the interactions of multiple spheres, it is recommended that the mineralization of exogenetic lithium deposits(resources) be investigated by integrating tectono-geochemistry, paleoatmospheric circulation, and salinology. So far, industrialized lithium extraction is primarily achieved in lithium deposits of the salt lake, clay, and hard rock types. The lithium extraction employs different processes, with lithium extraction from salt lake-type lithium deposits proving the most energy-saving and cost-effective.

Characteristics,Distribution Patterns,and Classification of Volcanic Reservoirs in the Huanghua Depression,Bohai Bay Basin,China

Identifying volcanic reservoir types and their distribution patterns in volcanic edifices is important for accurate prediction and exploration of hydrocarbon reservoirs.Herein,we analyzed the distribution patterns of different reservoir levels in volcanic edifices,discussed controlling factors,and reclassified reservoir types.This was done using core observations,whole-rock geochemistry,and reservoir physical property analysis,combined with logging,drilling,seismic,and oil-gas test data.Reservoirs can be divided into three classes based on their physical properties.The Mesozoic intermediate and basic rocks formed ClassⅠreservoirs,most lithologies formed ClassⅡreservoirs,and diabase intrusions and tight volcanic rocks formed ClassⅢreservoirs.Reservoirs form in different lithologies in the Huanghua depression due to weathering.Tectonic faults deepen the influence of weathering leading to the formation of reservoirs in tight.Additionally,volcanic rhythms and fractures control the vertical distribution of Cenozoic basaltic reservoirs.Volcanic reservoirs are classified into five types based on the main controlling factors and distribution patterns in volcanic edifices:tectonic-alteration,vesiclefracture,weathered-effusive,weathered-eruptive,and weathered-tectonic types.Among these,the weathered-eruptive type can easily form ClassⅠreservoirs,making it the best target for exploration.Whereas the weathered-tectonic and vesicle-fracture types tend to develop ClassⅡreservoirs and can be potential targets.The new classification takes into account the relationship between reservoir levels and their distribution in volcanic edifices,it is more conducive to igneous reservoir prediction in the Huanghua depression.This study provides a novel idea for the classification and comparative study of igneous reservoirs in petroliferous basins.

Formation mechanism of in-situ volcanic reservoirs in eastern China:A case study from Xushen gasfield in Songliao Basin

A large number of in-situ volcanic reservoirs have been discovered from the Meso-Cenozoic rift basin group in eastern China.Based on drilling results in combination with geological and geophysical analysis,a case study from the Early Cretaceous Xujiaweizi fault-depression shows that the formation mechanism of in-situ volcanic reservoirs is characterized by"fault-controlled body,body-controlled facies,facies-controlled reservoir,and reservoir-controlled accumulation".In other words,deep faults control the volcanic eruption type,volcanic body,and gas reservoir distribution;the volcanic body determines the spatial distribution of volcanic facies and volcanic gas reservoir size;the volcanic facies control reservoir physical properties and effective thickness of gas formation;the volcanic reservoir properties control gas reservoir type and gas productivity.The result is useful to guiding the discovery of in-situ volcanic gas reservoirs in faulted basins in both theory and practice.

Large and superlarge silver deposits associated with volcanic rocks in China

This paper deals with the geology and geochemistry of the Gacun and Laochang large-sized marine volcanic rock-type Ag deposits in the Sanjiang(Tri-River) area of southwestern China and of the continental volcanic-subvolcanic rock-type Ag deposits in the Tianshan area of Xinjiang, and in the East area,China. It is considered that the marine volcanic rock-type Ag deposits occur mainly in the second-ordered volcano-sedimentary basins developed in island-arc and rift tectonic environments.The Ag deposits show an obvious zonation,with vein-network mineralization in the lower parts and hot water sedimentary rock-hosted stratified mineralization in the upper parts. From the Earth抯 surface downwards the ore-forming elements follows the order of As(Au)→Ag,Pb,Zn→Cu. The whole rock Rb-Sr isotopic isochron age of layered orebodies in the Gacun deposit is 204±14 Ma, indicating that the main stage of mineralization is Late Triassic in age. The continental volcanic-subvolcanic (porphyry) rock-type Ag deposits were formed later than the country rocks. The ores exhibit disseminated, veinlet disseminated, network and lumped structures. In addition, this study also deals with the geochemical characteristics of the continental volcanic-subvolcanic rock-type Ag deposits and the relations between Ag deposits or silver itself and fluorite, halogen-family elements and manganese.