Drainage systems of Lonar Crater, India: Contributions to Lonar Lake hydrology and crater degradation

Goro Komatsu, P. Senthil Kumar, Kazuhisa Goto, Yasuhito Sekine, Chaitanya Giri, Takafumi Matsui

    Research output: Contribution to journalArticlepeer-review

    26 Citations (Scopus)

    Abstract

    Lonar, a 1.8-km-diameter impact crater in India, is a rare example of terrestrial impact craters formed in basaltic bedrock. The estimated age of the crater ranges widely from less than 12 ka to over 600 ka, but the crater preserves a relatively pristine morphology. We conducted a study of various drainage systems of Lonar Crater. The crater floor hosts a shallow 5-m-deep lake, which fluctuates seasonally. Our investigation reveals that the lake level is influenced by surface runoff that is active during the monsoon and groundwater input effective during both the rainy and the dry seasons. The groundwater discharge is observed as springs on the inner rim walls corresponding to weathered vesicular basalt and/or proximal ejecta, which are underlain by thick massive basalt layers. This observation indicates that groundwater movement is lithologically controlled: it passes preferentially through permeable vesicular basalt or proximal ejecta but is hindered in less permeable massive basalt. It is hypothesized that groundwater is also structurally controlled by dipping of basalt layers, interconnectivity of the permeable lithologic units through fractures, and preferential pathways such as fractures within the permeable lithologic units. Investigation on hydrological processes at Lonar Crater and its lake could provide useful insights into purported paleo-crater lakes presumably formed in the basaltic crust of Mars. The Lonar Crater interior shows signs of degradation in the forms of gullies and debris flows, and the Dhar valley incising in the rim leading to form a fan delta. The ejecta surface is characterized by the presence of channels, originating from the rim area and extending radially away from the crater center. The channels probably resulted from surface runoff, and its erosion contributes to the removal of the ejecta. Lonar Crater is a valuable analog site for studying degradation processes with potential application to impact craters occurring on hydrologically active ancient Mars, or to other impact craters on Earth.

    Original languageEnglish
    Pages (from-to)45-55
    Number of pages11
    JournalPlanetary and Space Science
    Volume95
    DOIs
    Publication statusPublished - 2014 May

    Keywords

    • Crater lake
    • Degradation
    • Drainage
    • Hydrology
    • Lonar
    • Mars

    ASJC Scopus subject areas

    • Astronomy and Astrophysics
    • Space and Planetary Science

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