期刊文献+
共找到3篇文章
< 1 >
每页显示 20 50 100
Large along-axis variations in magma supply and tectonism of the Southeast Indian Ridge near the Australian-Antarctic Discordance
1
作者 Shoujin Liu Jian Lin +1 位作者 Zhiyuan Zhou Fan Zhang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第1期118-129,共12页
We analyzed seafloor morphology and geophysical anomalies of the Southeast Indian Ridge(SEIR) to reveal the remarkable changes in magma supply along this intermediate fast-spreading ridge. We found systematic differen... We analyzed seafloor morphology and geophysical anomalies of the Southeast Indian Ridge(SEIR) to reveal the remarkable changes in magma supply along this intermediate fast-spreading ridge. We found systematic differences of the Australian-Antarctic Discordance(AAD) from adjacent ridge segments with the residual mantle Bouguer gravity anomaly(RMBA) being more positive, seafloor being deeper, morphology being more chaotic, M factors being smaller at the AAD. These systematic anomalies, as well as the observed Na8.0 being greater and Fe8.0 being smaller at AAD, suggest relatively starved magma supply and relatively thin crust within the AAD.Comparing to the adjacent ridges segments, the calculated average map-view M factors are relatively small for the AAD, where several Oceanic Core Complexes(OCCs) develop. Close to 30 OCCs were found to be distributed asymmetrically along the SEIR with 60% of OCCs at the northern flank. The OCCs are concentrated mainly in Segments B3 and B4 within the AAD at ~124°–126°E, as well as at the eastern end of Zone C at ~115°E. The relatively small map-view M factors within the AAD indicate stronger tectonism than the adjacent SEIR segments.The interaction between the westward migrating Pacific mantle and the relatively cold mantle beneath the AAD may have caused a reduction in magma supply, leading to the development of abundant OCCs. 展开更多
关键词 oceanic core complexes magma supply Southeast Indian Ridge lithospheric deformation Australian-Antarctic Discordance
下载PDF
The morphotectonics and its evolutionary dynamics of the central Southwest Indian Ridge (49° to 51°E) 被引量:8
2
作者 LIANG Yuyang LI Jiabiao +4 位作者 LI Shoujun RUAN Aiguo NI Jianyu YU Zhiteng ZHU Lei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第12期87-95,共9页
The morphotectonic features and their evolution of the central Southwest Indian Ridge (SWIR) are dis- cussed on the base of the high-resolution flfll-coverage bathyraetric data on the ridge between 49°-51°... The morphotectonic features and their evolution of the central Southwest Indian Ridge (SWIR) are dis- cussed on the base of the high-resolution flfll-coverage bathyraetric data on the ridge between 49°-51°E. A comparative analysis of the topographic features of the axial and flank area indicates that the axial topogra- phy is alternated by the ridge and trough with en echelon pattern and evolved under a spatial-temporal mi- gration especially in 49°-50.17°E. It is probably due to the undulation at the top of the mantle asthenosphere, which is propagating with the mantle flow. From 50.17° to 50.7°E, is a topographical high terrain with a crust much thicker than the global average of the oceanic crust thickness. Its origin should be independent of the spreading mechanism of ultra-slow spreading ridges. The large numbers of volcanoes in this area indicate robust magmatic activity and may be related to the Crozet hot spot according to RMBA (residual mantle Bouguer anomaly). The different geomorphological feature between the north and south flanks of the ridge indicates an asymmetric spreading, and leading to the development of the OCC (oceanic core complex). The tectonic activity of the south frank is stronger than the north and is favorable to develop the OCC. The first found active hydrothermal vent in the SWIR at 37°47'S, 49°39'E is thought to be associated with the detach- ment fault related to the OCC. 展开更多
关键词 ultra-slow spreading multibeam bathymetry MORPHOTECTONICS oceanic core complex Southwest Indian Ridge
下载PDF
Distribution of large-scale detachment faults on mid-ocean ridges in relation to spreading rates 被引量:2
3
作者 YU Zhiteng LI Jiabiao +3 位作者 LIANG Yuyang HAN Xiqiu ZHANG Jie ZHU Lei 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2013年第12期109-117,共9页
Large-scale detachment faults on mid-ocean ridges (MORs) provide a window into the deeper earth. They have megamullion on their corrugated surfaces, with exposed lower crustal and upper mantle rocks, rela- tively hi... Large-scale detachment faults on mid-ocean ridges (MORs) provide a window into the deeper earth. They have megamullion on their corrugated surfaces, with exposed lower crustal and upper mantle rocks, rela- tively high residual Bouguer gravity anomaly and P-wave velocity, and are commonly associated with ocean- ic core complex. According to 30 detachment faults identified on MORs, we found that their distances to the axis mostly range from 5 to 50 km, half-spreading rates range from 6.8 to 17 mm/a, and activity time ranges from recent to 3 Ma. Most of the detachment faults are developed on the slow spreading Mid-Atlantic Ridge (MAR) and ultra-slow spreading Southwest Indian Ridge (SWIRl, with the dominant half-spreading rates of 7-13 mm/a, especially 10-13 mm/a. Furthermore, they mostly occur at the inside corner of one segment end and result in an asymmetric seafloor spreading. The detachment faults on MORs are mainly controlled by the tectonism and influenced by the magmatism. Long-lived detachment faults tend to be formed where the ridge magma supply is at a moderate level, although the tectonism is a first-order controlling factor. At the slow spreading ridges, detachment faults tend to occur where local magma supply is relatively low, whilst at the ultra-slow spreading ridges, they normally occur where local magma supply is relatively high. These faults are accompanied by hydrothermal activities, with their relationships being useful in the study of hydrothermal polymetallic sulfides and their origin. 展开更多
关键词 detachment faults oceanic core complex spreading rates DISTRIBUTION TECTONISM magmasupply hydrothermal vents
下载PDF
上一页 1 下一页 到第
使用帮助 返回顶部