インド,ジャンム地域の中部シワリク系列のパーシャルインディペンデンス解析とエントロピー解析

概要

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The Middle Siwalik sediments of Jammu area consists of seven major lithofacies. A statistical analysis of lithofacies sequence using partial independence and entropy models reveals development of distinct cyclic order during deposition. The upward transition path of lithologic states typical for this sequence is as follows : Planar cross-bedded sandstone (A) → Trough cross-bedded sandstone (B) → Mixed planar and trough cross-bedded sandstone (C) → Ripple cross-bedded sandstone (D) → Mottled silty sandstone (E) → Clayey siltstone (F) → Heterolithic siltstone (G) → Planar crossbedded sandstone (A). This sequence is an asymmetrical cycle and can be identifid into facies which are a result of deposition in channels (lithofacies A-E), flood-plains (lithofacies F) and interfluve areas (lithofacies G). Entropy plots of the E^<(pre)> and E^<(post)> values of each lithological state correspond to the type A-4 category (Hattori, 1976), signifying lower and upper truncated asymmetrical cycles. The value of E_<(system)>falls within the boundaly allocated for fluvial-alluvial succession.
日本情報地質学会の論文
1999-09-25