ACORITE U-Pb CHRONOLOGY CHARACTERISTICS AND ITS GEOLOGICAL SIGNIFICANCE OF DUCTILE SHEAR DEFORMABLE BELT IN SOUTHEASTERN HAINAN ISLAND, CHINA
-
摘要: 海南东南部韧性剪切变形带断续出露于芒三水库—吊罗山林场—兴隆一线，走向北东，岩石有构造片麻岩和糜棱岩化花岗岩，主要矿物组成为长石、石英、黑云母。岩石发育“S-C”组构、“δ”型旋转碎斑系、云母鱼等变形组构，指示具有右行剪切活动的特点。根据矿物组成及变形特征，认为其变形环境相当于低角闪岩相，属于沿剪切带侵位并发生同步变形的产物。在芒三水库、吊罗山林场两地测得岩石锆石激光ICP-MS法年龄分别为284.3±1.3 Ma、265.9±1.3 Ma，属二叠纪形成。剪切变形带的发现及其年代学的厘定，对深入研究海南岛构造-岩浆作用具有重要的地质意义。Abstract: The ductile shear belt exposures in Mangsan Reservoir-Diaoluoshan Tree Farm-Xinglong area successively with its strike being north-east. The lithology is tectonic gneiss and granite of mylonitization, and main minerals are composed of feldspar, quartz and biotite. The rock develops as "S-C" fabric, "δ" style gyral porphyroclast system, mica fish etc. The tectonic fabric indicates right handed shearing movement. According to mineral component and deforming feature, the deforming environment should be low amphibolite facies, which belongs to the product emplacing across the shear zone and transforming synchronously. This time we got 284.3±1.3 Ma and 265.9±1.3 Ma by laser ICP-MS for zircons from Mangsan Reservoir and Diaoluoshan Tree Farm. The founding of ductile shear belt and its geologic age plays an important role in the intensive study of construction-magma function of Hainan Island.
-
Key words:
- deformable belt /
- synkinematic granite /
- Permian /
- Hainan Island
-
图 1 韧性剪切带地质简图
1—第四系；2—晚白垩世花岗斑岩；3—晚白垩世正长花岗岩；4—早白垩世二长花岗岩；5—早白垩世花岗闪长岩；6—晚侏罗世正长花岗岩；7—中三叠世二长花岗岩；8—晚二叠世正长花岗岩；9—晚二叠世二长花岗岩；10—地质界线；11—断裂；12—推测断裂；13—韧性变形带
Figure 1. Generalized geological map of ductile shear belt
图 2 吊罗山林业局河沟韧性剪切带剖面图
1—细粒黑云钾长花岗岩；2—煌斑岩；3—糜棱岩化花岗岩；4—构造片麻岩；5—构造片岩；6—掩盖；7—产状
Figure 2. Profile of ductile shear belt in the area of Diaoluoshan Forestry Bureau
图 5 构造岩石锆石激光ICP-MS法U-Pb年龄谐和图
Figure 5. Age concordancy diagram of acorite laser ICP-MS method
表 1 样品锆石ICP-MS测年结果
Table 1. Dating results of ICP-MS zircon from samples
-
[1] 张业明, 谢才富, 付太安, 等.三亚地体和琼中地体构造边界的直接证据[J].科学与工程, 2005, 5(20):1482~1484. http://www.cnki.com.cn/Article/CJFDTOTAL-KXJS200520003.htmZHANG Ye-ming, XIE Cai-fu, FU Tai-an, et al. The direct evidence about tectonic boundary between Sanya Terrain and Qiongzhong Terrain[J]. Science Technology and Engineering, 2005, 5(20):1482~1484. http://www.cnki.com.cn/Article/CJFDTOTAL-KXJS200520003.htm [2] 李孙雄, 范渊, 莫位明, 等.海南岛古生代弧状构造带的特征及其地质意义[J].矿产与地质, 2006, 20(3):232~236. http://www.cnki.com.cn/Article/CJFDTOTAL-KCYD200603005.htmLI Sun-xiong, FAN Yuan, MO Wei-ming, et al. Characteristics of arc structure zones in the Paleozoic era of Hainan island, and its geological implications[J]. Mineral Resources and Geology, 2006, 20(3):232~236. http://www.cnki.com.cn/Article/CJFDTOTAL-KCYD200603005.htm [3] 谢才富. 海南岛海西期同逆冲侵入岩组合的厘定及其构造意义[D]. 南京: 南京大学, 2007. http://d.wanfangdata.com.cn/Thesis/Y1435015XIE Cai-fu. Validation on Hercynian iso-thrusting irruptive rock assemblage in Hainan Island and its tectonic implication[D]. Nanjing:Nanjing University, 2007. http://d.wanfangdata.com.cn/Thesis/Y1435015 [4] 任纪舜.中国大地构造及其演化[M].北京:科学出版社, 1980.REN Ji-shun. Geotectonics and evolution in China[M]. Beijing:Science Press, 1980. [5] 杨树锋, 虞子冶, 郭令智, 等.海南岛的地体划分、古地磁研究及其板块构造意义[J].南京大学学报:地球科学版, 1989, 1(1/2):38~46.YANG Shu-feng, YU Zi-ye, GUO Ling-zhi, et al. Differentiation of Hainan terrane, the research of paleogeomagnetism and the significance of plate tectonics[J]. Journal of Nanjing University:Natural Sciences Edition, 1989, 1(1/2):38~46. [6] 谢才富, 朱金初, 赵子杰, 等.三亚石榴霓辉石正长岩的锆石SHRIMP U-Pb年龄:对海南岛海西-印支期构造演化的制约[J].高校地质学报, 2005, 11(1):47~57. http://www.cnki.com.cn/Article/CJFDTOTAL-GXDX200501002.htmXIE Cai-fu, ZHU Jin-chu, ZHAO Zi-jie, et al. Zircon SHRIMP U-Pb age dating of garnet-acmite syenite:Constraints on the Hercynian-Indosinian tectonic evolution of Hainan Island[J]. Geological Journal of China Universities, 2005, 11(1):47~57. http://www.cnki.com.cn/Article/CJFDTOTAL-GXDX200501002.htm -
下载:
点击查看大图
计量
- 文章访问数: 154
- HTML全文浏览量: 69
- PDF下载量: 10
- 被引次数: 0
