Incised Valleys in the Pleistocene Tenryugawa and Oigawa Coastal-Fan Systems, Central Japan: The Concept of the Fan-Valley Interval

  1. Henry W. Posamentier3,
  2. Colin P. Summerhayes4,
  3. Bilal U. Haq5 and
  4. George P. Allen6
  1. T. Muto

Published Online: 15 APR 2009

DOI: 10.1002/9781444304015.ch5

Sequence Stratigraphy and Facies Associations

Sequence Stratigraphy and Facies Associations

How to Cite

Muto, T. (1993) Incised Valleys in the Pleistocene Tenryugawa and Oigawa Coastal-Fan Systems, Central Japan: The Concept of the Fan-Valley Interval, in Sequence Stratigraphy and Facies Associations (eds H. W. Posamentier, C. P. Summerhayes, B. U. Haq and G. P. Allen), Blackwell Publishing Ltd., Oxford, UK. doi: 10.1002/9781444304015.ch5

Editor Information

  1. 3

    Plano, Texas, USA

  2. 4

    Godalming, UK

  3. 5

    Washington, DC, USA

  4. 6

    St Remy les Chevreuses, France

Author Information

  1. Department of Earth and Planetary Sciences, Kyusha University, Hakozaki 6-10-1, Kukuoka 812, Japan

  1. Department of Geology, Nagasaki University, Bunkyomachi 1-14, Nagasaki 852, Japan

Publication History

  1. Published Online: 15 APR 2009
  2. Published Print: 17 NOV 1993

ISBN Information

Print ISBN: 9780632035489

Online ISBN: 9781444304015



  • incised valleys in Pleistocene Tenryugawa and Oigawa coastal-fan systems, central Japan - concept of fan-valley interval;
  • terminology for alluvial-fan morphology in sea-level control model;
  • fan-valley interval;
  • model for tectonic control of fan-valley intervals;
  • relative sea-level changes;
  • Ogasayama Formation - multiple open-fan sequences;
  • sand-rich topset and foreset beds of B-type body of Ogasayama Formation;
  • improved sea level control model;
  • dimensions of dissectional morphology - on accumulation sites of overflow sediment


The fan-valley interval is a time interval between two successive periods of alluvial open-fan development corresponding with highstands of relative sea level. The 0.2 Ma-Recent Tenryugawa and 0.9–0.7 Ma Oigawa systems, both located on the Pacific coast of central Japan, experienced long and short fan-valley intervals, respectively, and show significant variations of coastal-fan sequences. Comparative analyses of the two systems, and of two fans of different ages in the Tenryugawa system, suggest that incised valleys form a significant portion of coastal-fan systems situated adjacent to steep submarine slopes. The sea-level control model of coastal fans, which has been improved so as to contain the concept of the fan-valley interval, gives a synthetic explanation to a considerable part of the observed variations.

During a fan-valley interval, a fan valley exists in a coastal-fan system and becomes wider owing to lateral erosion of the walls by the accommodating rivers. A long fan-valley interval, generally accompanying tectonic uplift, leads to: (i) large lateral dimensions of the fan valley and dissection channels; (ii) low frequency of overflow at the end of the interval; (iii) low productivity of the overflow sediments; and (iv) accumulation of the overflow sediments, if any, within the dissection channels rather than on the existing open-fan surface. The complete set of open-fan deposits tends to have bipartite organization and low-relief geometry after a long fan-valley interval and tripartite organization and high-relief geometry after a short fan-valley interval.