广西贵港市港南地区玄武岩地质特征及开发利用前景浅析

A Brief Analysis of the Geological Characteristics and Development & Utilization Prospects of Basalt in Gangnan Area, Guigang City, Guangxi

摘要: 本文以广西贵港市港南地区玄武岩为研究对象，通过野外地质调查、岩相学分析、地球化学测试及物理性能试验，系统研究了其地质特征、矿床成因及开发利用前景。研究表明，该区玄武岩赋存于大瑶山凸起带南翼博白–岑溪深大断裂带控制的登山岭岩体(J₂β)上部岩相带，呈似层状产出，属亚碱性系列，具有典型的斑状结构、块状、气孔及杏仁构造。主量元素显示其富集SiO₂ (42.60%~53.12%，平均46.79%)、Al₂O₃ (9.09%~15.14%)及Fe₂O₃ (8.64%~12.60%)，碱总量(K₂O + Na₂O)为5.86%。矿石物理性能优异，饱和抗压强度63.9 MPa~123 MPa (均值100.3 MPa)、吸水率0.51%~0.82% (均值0.63%)、磨耗损失率12.6%，且具有低碱活性(膨胀率 < 0.01%)与符合A类建材标准的放射性水平(Ira ≤ 0.4, Iγ ≤ 0.7)。矿床成因受印支–燕山期陆内裂谷背景下的基性岩浆侵入–喷溢作用及区域构造控制，浅部风化带与放射性异常区需分级开发。综合评价表明，该玄武岩矿床兼具优质建筑集料与高端新材料开发的潜力，研究结果为区域玄武岩资源的高效利用提供了地质参考依据。

Abstract: This study focuses on the basalt in Gangnan District, Guigang City, Guangxi, using field geological surveys, petrographic analysis, geochemical testing, and physical property experiments to systematically investigate its geological characteristics, ore genesis, and development potential. The research reveals that the basalt occurs in the upper lithofacies zone of the Dengshangling pluton (J₂β), which is controlled by the Baise-Cenxi deep fault zone in the southern wing of the Dayaoshan uplift belt. It is distributed in a sublayered manner, belongs to the subalkaline series, and exhibits typical porphyritic texture, massive structure, as well as vesicular and amygdaloidal textures. Major element analysis shows that it is rich in SiO₂ (42.60%~53.12%, average 46.79%), Al₂O₃ (9.09%~15.14%), and Fe₂O₃ (8.64%~12.60%), with a total alkali content (K₂O + Na₂O) of 5.86%. The ore exhibits excellent physical properties, including a saturated compressive strength of 63.9 MPa~123 MPa (average 100.3 MPa), water absorption of 0.51%~0.82% (average 0.63%), and abrasion loss of 12.6%. It also demonstrates low alkali reactivity (expansion rate < 0.01%) and radiation levels that meet Class A building material standards (IRa ≤ 0.4, Iγ ≤ 0.7). The genesis of the deposit is controlled by mafic magmatic intrusion and extrusion under the intracontinental rift setting of the Indosinian-Yanshanian period, as well as regional tectonics. The shallow weathering zone and areas with radioactive anomalies require graded development. Comprehensive evaluation indicates that this basalt deposit has potential for both high-quality construction aggregate and advanced new material development. The research findings provide a geological reference for the efficient utilization of basalt resources in the region.