Abstract The Laxmi and Laccadive ridges are two major aseismic ridges in the NW Indian Ocean. Bathymetry, gravity and magnetic data and their derivatives are analyzed and modelled to assess interrelationship between both the ridges as well as to establish their crustal structure, nature and isostatic compensation. Boundaries of the Laxmi and Laccadive ridges are delineated by tilt derivative with constraints from available seismic-sections. Integrated gravity and magnetic models reveal that both the ridges have almost similar crustal layers and are underplated all along its length. Crustal models also depict that both the ridges are carpeted with flood basalt and heavily intruded. 3D coherence between mantle Bouguer anomaly and residual bathymetry reveals that the elastic plate thickness and subsurface to surface load ratio for both the ridges vary from 3 to 4 km and 0.7 to 0.8, respectively. Several characteristic similarities viz. crustal structure and nature, elastic plate thickness, magmatism have been observed for both the ridges. Seismic sections near the junction of the ridges suggest that the basement high corresponding to the Laxmi Ridge is further continued towards the Laccadive Ridge. In addition, the northwestern part of the Laccadive Ridge has NW-SE structural lineaments similar to that of the NW-SE segment of the Laxmi Ridge. Based on results of the present and previous studies, we infer that (i) the Laxmi Ridge is extended southeastward towards the Laccadive Ridge, (ii) both the ridges are continental slivers which are underplated as well as intruded and carpeted by volcanics, and (iii) both the ridges are locally compensated.

中文翻译：

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Laxmi Ridge 是否继续向 Laccadive Ridge 延伸？综合地球物理研究的新见解

摘要 Laxmi 海脊和Laccadive 海脊是西北印度洋的两条主要抗震海脊。对水深、重力和磁力数据及其衍生物进行分析和建模，以评估脊之间的相互关系，并确定它们的地壳结构、性质和均衡补偿。Laxmi 和 Laccadive 海脊的边界由倾斜导数描绘，并受到可用地震剖面的约束。综合重力和磁力模型表明，这两个山脊具有几乎相似的地壳层，并且沿其长度方向都处于底镀层。地壳模型还描绘了两个山脊都覆盖着洪水玄武岩并被严重侵入。地幔布格异常和剩余水深测量之间的 3D 相干性表明，两个脊的弹性板厚度和地下与地表载荷比分别为 3 至 4 公里和 0.7 至 0.8 公里。几个特征相似之处即。两个山脊都观察到了地壳结构和性质、弹性板块厚度、岩浆活动。山脊交汇处附近的地震剖面表明，对应于拉克西米山脊的基底高度进一步向拉卡迪夫山脊延伸。此外，Laccadive Ridge 的西北部具有与 Laxmi Ridge 的 NW-SE 段相似的 NW-SE 构造线。根据目前和以前的研究结果，我们推断 (i) Laxmi Ridge 向东南向 Laccadive Ridge 延伸，