摘要
中国东南部和日本同处西太平洋构造-岩浆岩带,中生代均发育了大规模的侵入岩浆作用,但两者对比研究尚相对缺乏。通过对比中国东南部和日本中生代岩浆作用,发现二者既具有相似性,又具有明显的差异性。中国东南部和日本均经历了印支期后的岩浆作用沉寂期,中国东南部岩浆沉寂期为210~185 Ma,持续了约25Ma;而后中国东南部在170~150 Ma期间岩石圈发生伸展-减薄,导致大量的以黑云母二长花岗岩为主体的"改造型"或"陆壳重熔型"花岗岩类在南岭及其周边地区广泛出现,而在南岭以东的武夷山地区,发育大量的同时代的S型花岗岩及地壳增厚背景下形成的具埃达克质特征的花岗岩类,表明太平洋板块俯冲效应在该区已经显现。然而,日本未见该时期中酸性岩浆活动,日本中生代岩浆活动的沉寂期持续了约50Ma(180~130Ma)。中国东南部晚中生代大规模的岩浆侵入活动主要发生在145~80 Ma之间,并经历了121~117 Ma的动力变形作用;日本在140~100 Ma之间的花岗岩浆活动并不强烈,早期发育大洋俯冲板块熔融相关的埃达克质TTG和高镁安山岩组合,而峰期年龄介于100~60 Ma的花岗质岩石则部分经历了90~87 Ma的动力变形作用。日本晚中生代花岗质岩浆活动、动力变形作用明显比中国东南部大规模的花岗质岩浆活动晚约30~40 Ma。西南日本内带花岗质侵入岩在地质年代上呈现出由西向东逐渐变年轻的趋势,这一现象同中国东南部岩浆活动的迁移性是相同的,而且西南日本内带岩浆岩的同位素组成上也显示出明显的区域性变化。中国东南部中生代岩浆作用结束于80 Ma左右,以A型花岗岩及双峰式的岩浆岩的出现为主要标志;而日本的中生代花岗质岩浆活动则延续到古近纪,以挤压性地壳重熔的富含石榴石/白云母的S型花岗岩的出现为标志;这种差异性可能是由于两地地壳物质组成和性质存在较大的差别所致,中国东南部地壳是经历了多次造山构造旋回的高成熟度老地壳,而日本则可能是成熟度低的年轻地壳。
Southeast China and Japan are both belonging to the Pacific tectonic-magmatic belt with a large- scale of Mesozoic intrusive magmatism. Comparative study shows that they have similarities and differences. Both southeast China and Japan had experienced a period of silence after the Indosinian magmatism. The magmatic silence in southeast China had lasted for about 25 Ma ranging from 210-185 Ma, then lithospheric extension and thinning during 170-150 Ma led to the intrusion of the "transformation type" or "continental crust remelting type" granitoids in the Nanling and surrounding area, except for the Wuyi area where the magmatic rocks are dominated by S-type granites and adakitie rocks, indicating the influ- ence of the subduction of the Pacific plate in this area. However, the magmatic silence period in Japan had lasted for about 50 Ma (180-130 Ma), obviously longer than that in China. The late Mesozoic large scale magmatic intrusion occurred in southeast China between 145-80 Ma and experienced a dynamic de- formation at 121-117 Ma. Instead, the magmatism in Japan in 140-100 Ma is weak, and dominated by adakite and high-Mg andesite that derived from partial melting of subducted oceanic slab. The magmatism at 100- 60 Ma experienced a dynamic deformation during 87 -90 Ma. In comparison with those in the southeast China, the late Mesozoic granitic magmatism and dynamic deformation are about 30-40 Ma later in Japan. The Mesozoic granitic magmatism in Japan became younger from west to east and similar with that in southeast China. The disappearance of Mesozoic magmatism in southeast China is characterized by the occurrence of A-type granite and bimodal volcanism at 80 Ma ago. The Mesozoic granitic magmatism in Japan lasted up to Paleogene, characterized by the appearance of the garnet/muscovite-bearing S-type granite. The differences is probably caused by the difference in compositions and properties of the crust, the crust in southeast China was composed of old crust material that had experienced several orogenic cycles, whereas Japan might have a younger crust.
作者
赵希林
于胜尧
李三忠
彭银彪
姜杨
邢光福
余明刚
刘凯
ZHAO Xilin YU Shengyao LI Sanzhong PENG Yinbiao JIANG Yang XING Guangfu YU Minggang LIU Kai(Nanjing Center,China Geological Survey, Nanjing 210016, China Key Lab of Submarine Geoseiences and Prospecting Techniques, MOE and College of Marine Geoscienees, Ocean University of China, Qingdao 266100, China Institute of Geology, Chinese Academy of Geological Sciences, Beijing 100037, China)
出处
《海洋地质与第四纪地质》
CAS
CSCD
北大核心
2017年第4期65-82,共18页
Marine Geology & Quaternary Geology
基金
国家重点研发计划课题(2016YFC0600205)
中国地质调查局地质矿产调查项目(DD20160037)
泰山学者特聘教授计划