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Title
  • ja 有峰層（Oxfordian階中部）の堆積相（富山県域の上部ジュラ系九頭竜層群－第1報－ 補遺）
Alternative
  • en Supplementary information to “Ichnofossil assemblage and sedimentary facies of the middle Oxfordian Arimine Formation, southeastern Toyama Prefecture”
Creator
    • ja 平澤, 聡
Subject
  • Other Oxfordian階
  • Other 有峰層
  • Other 堆積相解析
  • Other 堆積相
  • Other 生痕相
  • Other Oxfordian
  • Other Arimine Formation
  • Other facies analysis
  • Other sedimentary facies
  • Other ichnofacies
Description
  • Other 富山市有峰地域（真川上流域）に分布する，九頭竜層群有峰層（Oxfordian階中部）について3種類の堆積相（堆積相1−3）を認定し，それらの堆積環境および生痕相について考察した．堆積相1は著しい生物撹拌を受けた斑紋状の細粒砂岩であり，Cruziana生痕相の化石棲管を多産する．堆積相2は，中−強度の生物撹拌を被ったスウェール状斜交層理（SCS）細粒砂岩からなり，Cruziana生痕相の生痕化石を含む．堆積相3は，明瞭なSCSとわずかに認められるSkolithos生痕相の要素で特徴づけられる細粒砂岩である．これらの堆積相は，“moderately storm-dominated”型の外浜環境を示唆する．また暴浪の発生に関連して，底生群集の組成が平衡種から日和見的に入植した種へと周期的に変化したことを示す．
  • Other Supplement to the facies analysis of the middle Oxfordian Arimine Formation is presented. The studied section exposed at the southeastern part of Toyama Prefecture (36°27'59.98"N, 137°28'52.05"E) consists of alternating beds of storm-influenced and bioturbated sandstones (or “lam-scram” sequence) containing a mixed Skolithos-Cruziana ichnofacies asemblage. The section is classified into the following three sedimentary facies types: facies 1, mottled fine-grained sandstone with Cruziana ichnofacies elements (Palaeophycus, Planolites and horizontal tunnels of Ophiomorpha); facies 2, swaley cross-stratificated fine-grained sandstone affected by moderate to strong bioturbation due to Cruziana ichnofacies elements as occurred in the facies 1, and facies 3, weakly burrowed, swaley cross-stratificated fine-grained sandstone enclosing Skolithos ichnofacies elements (shafts of Ophiomorpha and Skolithos). They are suggested to reflect a “moderately storm-dominated” type of middle to lower shoreface environments deposited during fair-weather conditions (facies 1, bioturbated lithology of facies 2), and cyclic storm events (swaley cross-stratification in facies 2, facies 3). The trace fossil assemblages are interpreted as periodic changes from opportunistic (Skolithos ichnofacies) to equilibrium (Cruziana ichnofacies) benthic communities related to the storm events and fair-weather conditions.
Publisher 富山市科学博物館
Date
    Created2018-10-30 , Issued2017-06-20
Language
  • jpn
Resource Type departmental bulletin paper
Version Type VoR
Identifier URI http://repo.tsm.toyama.toyama.jp/?action=repository_uri&item_id=1072
Relation
  • isIdenticalTo NAID 120006632467
Journal
    • NCID AA12306127
    • ISSN 1882-384X
      • 富山市科学博物館研究報告 = Bulletin of the Toyama Science Museum
      • Volume Number41 Page Start1 Page End8
File
Oaidate 2022-10-02