0 引言
1 数据和方法
1.1 数据来源及构造识别
图1 研究区地形图(水深数据来源于中国大洋24航次;投影方式为高斯-克吕格;地形分辨率为50 m;右上角的小地图为印度洋洋中脊分布图,图中的红线为洋中脊线,黄线为板块边界,红色五角星为研究区位置。) Fig.1 Topographic map of the study area (The bathymetric data are sourced from the DY24 Cruise. The projection method is Gauss-Kruger. The grid resolution is 50 m. The small globe map in the upper right corner is the distribution map of Indian Ocean ridges, the red line in the map is the mid-ocean ridge line, the yellow line is the plate boundary, and the red five-pointed star is the location of the study area.) |
1.2 定量分析方法
1.2.1 断层相关指数的计算
1.2.2 莫兰指数的计算
1.2.3 核密度的计算
1.2.4 岩浆作用强度的计算
2 结果
2.1 研究区地形特征
图5 4个洋中脊段典型剖面图(图中黑色虚线代表断层。) Fig.5 Typical cross-sections of four mid-ocean ridge segments (The black dotted lines in the figure are the faults.) |
表1 洋中脊A、B、C和D段的形态和一些重要构造特征参数Tab.2 Morphology and some important structural feature data of mid-ocean ridge segments A, B, C and D |
名称 | 脊段 长度 /km | 轴部 裂谷 宽度/km | 最大 水深/m | 轴部 裂谷 高度/m | AVR 高度/m | 轴部裂谷 高宽比/ (×10-3) |
---|---|---|---|---|---|---|
洋中脊A段 | 14.0 | 4 075 | ||||
剖面1 | 13.6 | 4 068 | 900 | 130 | 66.2 | |
剖面2 | 10.3 | 3 952 | 801 | 163 | 77.8 | |
剖面3 | 9.5 | 3 460 | 683 | 280 | 71.9 | |
剖面4 | 8.9 | 3 901 | 860 | 112 | 96.6 | |
洋中脊B段 | 40.0 | 4 175 | ||||
剖面5 | 9.5 | 4 087 | 884 | 405 | 93.1 | |
剖面6 | 9.1 | 4 148 | 1 313 | 685 | 144.3 | |
剖面7 | 10.4 | 3 980 | 1 467 | 667 | 141.1 | |
剖面8 | 9.5 | 3 556 | 1 012 | 528 | 106.5 | |
剖面9 | 10.2 | 3 548 | 1 004 | 322 | 98.4 | |
剖面10 | 9.8 | 3 700 | 1 102 | 500 | 112.4 | |
剖面11 | 9.7 | 3 972 | 1 148 | 580 | 118.4 | |
剖面12 | 9.8 | 3 957 | 1 617 | 451 | 165.0 | |
剖面13 | 9.4 | 4 016 | 1 673 | 251 | 178.0 | |
剖面14 | 8.9 | 3 947 | 1 340 | 220 | 150.6 | |
洋中脊C段 | 21.0 | 4 370 | ||||
剖面17 | 16.9 | 4 343 | 1 013 | 306 | 59.9 | |
剖面18 | 15.5 | 4 125 | 1 092 | 461 | 70.5 | |
剖面19 | 13.8 | 4 141 | 1 197 | 603 | 86.7 | |
剖面20 | 14.6 | 4 087 | 957 | 660 | 65.5 | |
剖面21 | 13.7 | 4 028 | 697 | 832 | 50.9 | |
洋中脊D段 | 17.5 | 3 920 | ||||
剖面22 | 20.9 | 3 845 | 1 429 | 275 | 68.4 | |
剖面23 | 20.5 | 3 782 | 996 | 391 | 48.6 | |
剖面24 | 15.4 | 3 648 | 953 | 202 | 61.9 | |
剖面25 | 14.8 | 3712 | 643 | 258 | 43.4 |