摘要
哈尔郭勒玄武岩位于东昆仑南缘布青山地区.详细的地球化学研究表明哈尔郭勒玄武岩可以分为碱性玄武岩和亚碱性玄武岩,其中碱性玄武岩的∑LREE=63.8×10-6～ 175.36×10-6,∑HREE=14.46× 10-628.56× 10-6,∑LREE/∑HREE=4.41～6.14,（La/Yb）N=4.14～6.71,（Ce/Yb）N=3.31～5.12,δEu=1.03～1.17,具有与洋岛玄武岩（OIB）相似的稀土配分模式;亚碱性玄武岩的∑LREE=1 1.07× 10-6～29.95×10-6,∑HREE=12.56× 10-6～25.41×10-6,∑LREE/Σ HREE=0.88～1.54,（La/Yb）N=0.29～0.74,（Ce/Yb）N=0.37～0.77,δEu＝1.02＝1.22,具有正常洋中脊玄武岩（N-MORB）的稀土元素地球化学特征.这表明哈尔郭勒玄武岩是OIB与N-MORB的共生组合.布青山地区哈尔郭勒玄武岩中的OIB形成于洋脊附近的海山或洋岛环境,岩浆源区可能为EMⅡ型富集地幔;N-MORB形成于洋脊环境,起源于亏损地幔.哈尔郭勒玄武岩为布青山地区晚古生代存在洋盆提供了更充分的证据.
The Haerguole seamount basalt is located in Buqingshan area on the southern margin of the East Kunlun Mountains.Detailed geochemical analysis shows that the Haerguole seamount basalt can be divided into alkaline basalts and subalkaline basalts.The REE distribution patterns of alkaline basalts are similar to those of OIB,with the data Σ LREE=63.8 × 10-6～ 175.3 6 × 10-6,Σ HREE=14.46 × 10-6～28.56× 10-6,Σ LREE/Σ HREE=4.41～6.14,（La/Yb）N=4.14～6.71,（Ce/Yb）N=3.31～5.12,and δEu=1.03～1.17.The REE distribution patterns of subalkaline basalts are similar to those of N-MORB,with the data Σ LREE=1 1.07× 10-6～29.95× 10-6,Σ HREE=12.56 × 10-6～25.41 × 10-6,Σ LREE/Σ HREE=0.88～1.54,（La/Yb）N=0.29～0.74,（Ce/Yb）N＝0.37～0.77 and δEu=1.02～1.22.These geochemical characteristics suggest that the Haerguole basalt is the association of OIB and N-MORB.The OIB of Haerguole seamount basalt was formed in a seamount or an ocean island setting near the mid-ocean ridge,and OIB magma originated from EM Ⅱ-type enriched mantle.The N-MORB was formed in a mid-ocean ridge setting and originated in depleted mantle.These data provide more evidence for the existence of ocean basin in Buqingshan area in Late Paleozoic.
出处
《中国地质》
CAS
CSCD
北大核心
2014年第2期335-350,共16页
Geology in China
基金
国家自然科学基金项目(41172186)
中央高校基本科研业务费专项资金项目(2013G1271091
2013G1271092
CHD2011TD020)
青海省国土资源厅-中国铝业公司公益性区域地质矿产调查基金项目(中铝基金200801)共同资助
