GEOCHEMICAL RESEARCH INTO ORIGINS OF TWO TYPES OF MESOZOIC RHYOLITES IN DAXING'ANLING
-
摘要: 大兴安岭地区晚侏罗世—早白垩世流纹岩类广泛分布.根据岩石学和微量元素地球化学特征将其划分为两类, 分别称其为Ⅰ型流纹岩和Ⅱ型流纹岩.稀土和微量元素分析结果显示: (1) Ⅰ型流纹岩呈右倾的稀土分布曲线, 不相容元素以强烈富集Rb, Ba, Th, K和亏损Sr, Ti, P, Nb为特征, 其形成与钙碱性系列玄武岩浆的结晶分异作用有关; (2) Ⅱ型流纹岩具有与大陆裂谷流纹岩一致的稀土和不相容元素分布模式, 以Ba, Sr的强烈亏损与I型流纹岩相区别, 与碱性系列玄武岩类构成双峰式火山岩组合, 其成因与地壳岩石的非理想熔融作用相联系.两类流纹岩的形成与地幔柱上涌导致上覆岩石圈伸展作用有关.Abstract: Widely exposed in Daxing'anling region are Late Jurassic and Early Cretaceous rhyolites that are classified as two major types in terms of petrology and trace-element geochemistry: Type-I rhyolite and Type-II rhyolite. The following conclusions can be drawn from the results in rare earth and trace elements:(1)Type-I rhyolite is characterized by the right-sloped REE distribution pattern. The incompatible elements in this type are featured by both the strong enrichment of Rb, Ba, Th, and K and the depletion of Sr, Ti, P, Nb. These features are related to the crystal differentiation of the calc-alkaline basaltic magma.(2)Type-II rhyolite is characterized by the REE and incompatible-element distribution pattern. The strong depletion of Ba and Sr in this type, a distinctive feature from Type-I rhyolite, established a bimodal volcanic association with alkaline basalts, whose origins are associated with the non-ideal melting of crustal rock. In addition, the formation of these two typesof rhyolitesis related to the extension of overlying lithosphere resulting from the upwelling of mantle-plume.
-
Key words:
- rhyolites /
- geochemistry /
- petrogenesis /
- Daxing'anling
-
图 1 大兴安岭中生代火山岩分布
Fig. 1. Sketch map showing distribution of Mesozoic volcanic rocks in Daxing'anling
图 3 大兴安岭流纹岩类REE分布曲线
a.Ⅰ型流纹岩; b.Ⅱ型流纹岩
Fig. 3. REE patterns of Mesozoic rhyolites in Daxing'anling
图 4 大兴安岭流纹岩不相容元素的原始地幔标准化
a.Ⅰ型流纹岩; b.Ⅱ型流纹岩
Fig. 4. Primitive mantle＿normalized incompatible elements spidergram for rhyolites in Daxing'anling
表 1 大兴安岭中生代流纹岩类主量元素和微量元素分析结果
Table 1. Major and trace element compositions of Mesozoic rhyolites in Daxing'anling
-
[1] 任纪舜, 姜春发, 张正坤, 等. 中国大地构造及其演化——1∶400万中国地质构造图简要说明[M]. 北京: 科学出版社, 1980. 1~124. [2] 王听渡, 张秀棋, 徐永生. 内蒙古昭乌达盟地区中生代火山岩岩石特征及成因探讨[J]. 岩石学报, 1985, 1(2): 74 ~87. doi: 10.3321/j.issn:1000-0569.1985.02.010 [3] 蒋国源, 权恒. 大兴安岭根河、海拉尔盆地中生代火山岩[J]. 中国地质科学院沈阳地质矿产研究所所刊, 1988, (17): 23~100. https://cpfd.cnki.com.cn/Article/CPFDTOTAL-ZGDJ198800019003.htm [4] 赵国龙, 杨桂林, 傅嘉友, 等. 大兴安岭中南部中生代火山岩[M]. 北京: 科学技术出版社, 1989. 1~260. [5] 张德全, 鲍修文. 内蒙古白音诺中酸性火山-深成杂岩体的岩石学、地球化学与成因研究[J]. 地质论评, 1990, 36(4): 289~297. doi: 10.3321/j.issn:0371-5736.1990.04.001 [6] 许文良, 孙德有, 周燕. 满洲里-绥芬河地学断面岩浆作用和地壳结构[J]. 北京: 地质出版社, 1994. 1~94. [7] 林强, 葛文春, 孙德有, 等. 东北地区中生代火山岩的大地构造意义[J]. 地质科学, 1998, 33(2): 129~139. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKX802.000.htm [8] 葛文春, 林强, 孙德有, 等. 大兴安岭中生代玄武岩的地球化学特征: 壳-幔相互作用[J]. 岩石学报, 1999, 15 (3): 397~407. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB199903007.htm [9] Middlemost E A K. Naming materials in magma/igneous rock system[J]. Earth Science Reviews, 1994, 37: 215~ 224. [10] Irvine T N, Baragar W R A. A guide to the chemical classification of the common volcanic rocks[J]. Canadian Journal of Earth Sciences, 1971, (8): 523~548. [11] Wilson M. Igneous petrogenesis[M]. London: Unwin Hyman, 1989. 1~466. [12] Macdonald R, Davies G R, Bliss C M, et al. Geochem- istry of high_silica peralkaline rhyolites, Naivasha, Kenya Rift Valley[J]. J Petrology, 1987, 28(6): 979~1008. [13] Whalen J B, Currie K L, Chappell B W. A_type granites: geochemical characteristics, discrimination and petrogene- sis[J]. Contrib Mineral Petrol, 1987, 95: 407~419. [14] 干国梁. 矿物-熔体间元素分配系数资料及主要变化规律[J]. 岩石矿物学杂志, 1993, 12(2): 144~181. https://www.cnki.com.cn/Article/CJFDTOTAL-YSKW199302006.htm [15] Arculus R J. The significance of source versus process in the tectonic controls of magma genesis[J]. J Volcano Geothem Res, 1987, 32: 1~12. [16] 陶奎元. 中国东南大陆火山带在环太平洋带中的独特地位[A]. 见: 李兆鼐, 王碧香主编. 火山岩、火山作用及有关矿产[C]. 北京: 地质出版社, 1993. 23~30. [17] 樊祺诚, 刘若新, 张国辉, 等. 长白山望天鹅火山双峰式火山岩的成因演化[J]. 岩石学报, 1998, 14(3): 305~ 317. https://www.cnki.com.cn/Article/CJFDTOTAL-YSXB803.004.htm [18] 李培忠, 于津生. 黑龙江碾子山晶洞碱性花岗岩岩体的年龄及其意义[J]. 地球化学, 1994, (4): 389~398. https://www.cnki.com.cn/Article/CJFDTOTAL-DQHX199304008.htm [19] 王一先, 赵振华. 巴尔哲超大型稀土铌铍锆矿床地球化学和成因[J]. 地球化学, 1997, 26(1): 24~35. https://www.cnki.com.cn/Article/CJFDTOTAL-DQHX701.002.htm [20] 张履桥, 邵济安, 郑广瑞. 内蒙古甘珠尔庙变质核杂岩[J]. 地质科学, 1998, 33(2): 140~146. https://www.cnki.com.cn/Article/CJFDTOTAL-DZKX802.001.htm -
下载:
点击查看大图
计量
- 文章访问数: 4071
- HTML全文浏览量: 539
- PDF下载量: 13
- 被引次数: 0
