Cassiterite U-Pb dating of the Yelonggou pegmatite-type lithium deposit in western Sichuan and its metallogenic age constraints

1.Objective Pegmatite hosts important resource of rare metals,e.g.,lithium(Li)and beryllium(Be).In recent years,increasingly more studies were dedicated to characterize and unravel the formation of pegmatite-type deposits,for which accurate dating of pegmatite formation and mineralization is essential.The Songpan-Ganzi orogenic belt is a major rare metal metallogenic belt in China,hosting many important pegmatite-type Li deposits,including the Lijiagou,Dangba,Jiajika,Yelonggou,Cuola,and Declalongba.Radiometric age data(mica Ar-Ar and zircon/cassiterite U-Pb)from these Li deposits are sparse,ranging from 210 to 152 Ma.However,obtaining reliable zircon U-Pb dates can be a challenge due to the strong decidualization in pegmatites.As a result,the formation and mineralization ages of these rare metal pegmatites remain controversial,which hampers the development of pegmatite-type metallogenic model for the Songpan-Ganzi orogenic belt.

Discovery of the pegmatite lithium veins with predicted super-large size resources in the Sizemuzu district of the Keeryin,China

1.Objectives Keeryin rare metal ore district is located at the intersection of Markam,Jinchuan and Rangtang counties.More than 1000 pegmatite dykes are associated with the Keeryin granite pluton.These pegmafite dykes are the major source of industrial spodumene ore bodies.Based on the previous studies,we chose Keeryin rare metal ore district as the key target area for geology survey.In this study,we discovered six pegmatite lithium veins in the Sizemuzu district of the Keeryin.Moreover,we study the distribution of regional ore deposits and metallogeny,delineate prospecting target and evaluate the mineralization potential of Lithium.

Potential application of ultrasound-guided thermal ablation in rare liver tumors

Background: With the advances of imaging techniques, the detection rate of rare liver tumor is increased. However, the therapeutic strategies of the rare liver tumors remain limited. Methods: We analyzed twelve pathologically confirmed rare liver tumors in 8 patients. All of the patients underwent ultrasound(US) guided biopsy and subsequent thermal ablation. The tumors were ablated according to the preoperative plans and monitored by real-time US. CT/MRI fused with contrast enhanced US(CEUS) or three-dimensional(3 D) US-CEUS images were used to guide and assess the ablation zone more accurately during thermal ablation. The rate of technical efficacy was assessed based on the contrast-enhance CT/MRI(CECT/MRI) results one month after ablation. Local tumor progression(LTP), recurrence and complications were followed up and recorded. Results: Among these twelve nodules, nine were subject to US-guided thermal ablation, whereas the other three inconspicuous nodules were subject to CEUS-guided thermal ablation. Intra-procedure CT/MRI-CEUS or 3 D US-CEUS fusion imaging assessments demonstrated that the ablation zone sufficiently covered the original tumor, and no immediate supplementary ablation was required. Additionally, no major complications were observed during the follow-up period. The postoperative CECT/MRI confirmed that the technique success rate was 100%. Within the surveillance period of 13 months, no LTP or recurrence was noted. Conclusions: US-guided thermal ablation was feasible and safe for rare liver tumors. The use of fusion imaging technique might make US-guided thermal ablation as effective as surgical resection, and this technique might serve as a potential therapeutic modality for rare liver tumors in the future.