Genesis and magma fertility of gold associated high-K granites:LA-ICP-MS zircon trace element and REEs constraint from Bakoshi–Gadanya granites in NW Nigeria

High-K granites dominate the rock units in the Bakoshi and Gadanya areas located in the northwestern Nigerian subshield,part of the Trans-Saharan Belt,West Africa.In this contribution,the LA-ICP-MS zircon trace element revealed the fertility of magma responsible for the high-K granites that hosts the Bakoshi–Gadanya gold mineralization.Two likely metallogenic granites types are 1)Gadanya alkali granite,with high Ce^(4+)/Ce^(3+)(mean 1485)and limited range of Eu anomalies may likely be associated with the gold mineralization,and 2)Bakoshi porphyritic granite,Jaulere biotite granite,Shanono coarsegrained granite,and Yettiti granite,all have low Ce^(4+)/Ce^(3+) ratios(mean\100,except second Bakoshi granite D2-1)with wider ranges of Eu/Eu^(*) values,thus are considered reduced granites.These reduced granites have oxygen fugacity values and Eu anomalies comparable to reduced granites associated with tin belts in Myanmar and Zaaiplaats granites in Bushveld Complex,South Africa.Ti-inZircon thermometric study revealed two thermal regimes during the crystallization of the Bakoshi–Gadanya granites:the high temperature(746–724℃):Shanono coarsegrained granite,Bakoshi granite D2-1,and Jaulere biotite granite;and relatively low temperature(705–653℃):Bakoshi porphyritic granite D1-1,Yettiti medium-grained granite,and Gadanya alkali granite.Zircon trace elements including U,Yb,Y,Nb,and Sc ratios constraint the magma source of Bakoshi–Gadanya granites to an enriched mantle metasomatized during the subduction process before its melting.Except for Gadanya alkali granite,fractionation of titanite and apatite dominate the magma evolution with limited amphibole fractionation.Melt that crystallized Gadanya alkali granite is rather saturated in zircon without accessory titanite or apatite.

Distributional Chaoticity of the Minimal Subshift of Shift Operators

This paper focus on the chaotic properties of minimal subshift of shift operators. It is proved that the minimal subshift of shift operators is uniformly distributional chaotic, distributional chaotic in a sequence, distributional chaotic of type k ( k∈{ 1,2,2 1 2 ,3 } ), and ( 0,1 ) -distribution.

Exhumation History and Exploration Potential of Gold Deposits in the NE Jiaodong Peninsula,North China:Evidence from Apatite and Zircon Fission Track Thermochronology

As the most important gold producer in China,the Northwest Jiaodong Peninsula is famous for its large gold deposits.In recent years,the discovery of gold mineralization has reached a depth of 4000 m below the surface in this region.It has attracted significant interest from explorers about the prospecting potential at greater depths.Besides,the current deep drilling shows that the prospecting effect in the west portion is better than the region to the east.Does it imply that there is a difference in prospecting potential between the east and the west?This paper seeks to address the issue through fission track thermochronology on apatite and zircon to reveal the temperature-time evolution relationship of rock mass and to inverts their thermal evolution history.In addition,this study analyzes the transformation of ore deposits after mineralization,quantitatively calculates the uplift-erosion rate of rock mass,and summarizes the preservation law of ore deposits.Based on the thermal history simulation of the apatite fission track,our results show that the Guocheng gold belt has experienced three stages of thermal evolution:108-74,74-27,and 27-0 Ma.The uplift and cooling processes of the threestage tectonic uplift events are the results of multi-stage Pacific plate accretion.The calculated total denudation depth of the gold deposit in the Guocheng gold belt from Cretaceous to the present is about 3.4-5.3 km.The metallogenic depth of the ore body in the gold belt is 5.6-8.0 km,which indicates that the ore body in the Guocheng gold belt has suffered a significant degree of denudation.It is speculated that the location with less denudation in the southwest has greater prospecting potential.Our results quantitatively identify the uplift and denudation of the deposit after mineralization,which provides a new theoretical reference for regional mineralization,deep prospecting and exploration.

Analysis of Review Helpfulness Based on Consumer Perspective

When consumers make purchase decisions, they generally refer to the reviews generated by other consumers who have already purchased similar products in order to get more information. Online transaction platforms provide a highly convenient channel for consumers to generate and retrieve product reviews. In addition,consumers can also vote reviews perceived to be helpful in making their decision. However, due to diverse characteristics, consumers can have different preferences on products and reviews. Their voting behavior can be influenced by reviews and existing review votes. To explore the influence mechanism of the reviewer, the review,and the existing votes on review helpfulness, we propose three hypotheses based on the consumer perspective and perform statistical tests to verify these hypotheses with real review data from Amazon. Our empirical study indicates that review helpfulness has significant correlation and trend with reviewers, review valance, and review votes. In this paper, we also discuss the implications of our findings on consumer preference and review helpfulness.