摘要
西拉木伦钼铜多金属成矿带处于华北克拉通与中亚造山带的过渡区,是古生代古亚洲构造域与中生代西太平洋构造域的交汇部位。在中生代受多种构造体系的制约,如中亚造山带造山后期局部伸展、蒙古-鄂霍茨克俯冲-碰撞造山作用、古太平洋板块的向西俯冲和中国东部岩石圈减薄事件的影响等。西拉木伦成矿带成矿斑岩锆石U-Pb年龄和辉钼矿Re-Os同位素年龄资料显示,钼铜矿成岩成矿主要集中在260～220Ma、180～150Ma和140～120Ma三个时期。结合华北克拉通北缘构造演化历史,推测这三期成矿作用主要与造山后局部伸展、构造体系转折和陆内伸展(岩石圈减薄)过程有关,并相应建立了"车户沟式"、"鸡冠山式"和"敖伦花式"三类斑岩钼铜矿床成矿模式。进一步研究表明,岩石的酸碱性、岩浆来源、岩浆的氧逸度、岩浆演化方式、构造背景等因素,制约了成矿作用的专属性。
The Xilamulun metallogenic belt,located between Central Asian Orogenic Belt and North China Craton,is situated at the junction between the Paleo-Asian Ocean and the west Circum-Pacific tectonic regime.The ore belt was controlled by some tectonic systems,such as post-collisional extension of the Central Asian Orogenic Belt,Mongolia-Okhosk orogen,west Circum-Pacific tectonic and lithosphere large-scale thinning.Molybdenite Re-Os and zircon U-Pb dating of the Xilamulun ore belt show three periods of mineralizations which occurred at 260 ～ 220Ma,180 ～ 150Ma and 140 ～ 120Ma,respectively.Combined with the regional geology and geochemical study,we suggest that the mineralizations in the belt were formed during multiple geodynamic settings.The mineralization in 260 ～ 220Ma is probably related to a post-collisional extension stage with the generation of the porphyry molybdenum-copper deposits;The stage of 180 ～ 150Ma is related to a tectonic stress transformation from NS to EW;The large-scale mineralization occurred at 140 ～ 120Ma is related to the lithosphere thinning due to the upwelling of asthenosphere under the intra-continent extension.Based on geology and geochemistry of Mo-Cu deposits,authors suggest three ore-forming modes:i.e.'Chehugou','Jiguanshan'and 'Aolunhua'-types.Study data show that ore-forming specialization are restricted by acid-alkali degree of host rock,magma source,oxygen fugacity of rock,evolvement fashion of magma and tectonic setting.
出处
《岩石学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第5期1351-1362,共12页
Acta Petrologica Sinica
基金
国家重点基础研究发展规划项目(2006CB403506)资助
关键词
斑岩矿床
成矿专属性
中生代
西拉木伦成矿带
华北克拉通北缘
Porphyry deposit
Mineralization specialization
Mesozoic
Xilamulun metallogenic belt
Northern margin of North China Craton
