, Volume 50, Issue 1, pp 133–145 | Cite as

Necoslie breccia: mixed conodont fauna-bearing neptunian dyke in Carboniferous-Permian seamount-capping oceanic buildup (Pope succession, Cache Creek Complex, central British Columbia)

  • H. SanoEmail author
  • M. J. Orchard
Original Article


A mixed conodont fauna-bearing limestone breccia, informally designated as Necoslie breccia, crops out as an internal sediment hosted by the Lower Moscovian limestone unit of the Pope limestone succession (Bashkirian to Asselian) of Cache Creek Complex in central British Columbia, reconstructed as a mid-oceanic buildup upon a seamount, or an oceanic plateau. Necoslie breccia consists predominantly of limestone fragments derived from the host rocks, with subordinate isolated skeletal debris, all embedded in a matrix of fine-grained clastic carbonates. The mixed conodont fauna yields the youngest element indicative of Carnian. Our microscopic examination and conodont paleontological data show that Necoslie breccia is better defined as a neptunian dyke formed by infilling sedimentation of carbonates in a fracturing-generated submarine cavity, rather than a karstic cave-fill deposit. We postulate that infilling sedimentation took place immediately after the formation of the cavity, most likely in a transgression period during Carnian time.


Necoslie breccia neptunian dyke mid-oceanic buildup mixed conodont fauna Cache Creek Complex 



This study was done as part of the Nechako NATMAP project run by the Geological Survey of Canada and British Columbia Geological Survey from 1995 to 2000. The authors express our sincere thanks to Dr. L. C. Struik (Geological Survey of Canada, Vancouver) for his fruitful discussion on the geology of the study area. We greatly thank Dr. L. Rui (Geological Survey of Canada, Calgary), who provided important suggestions relevant to the age of fusulines found in Necoslie breccia. Critical review by two journal reviewers much improved the manuscript.


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Copyright information

© Springer-Verlag 2004

Authors and Affiliations

  1. 1.Department of Earth and Planetary SciencesKyushu UniversityFukuokaJapan
  2. 2.Geological Survey of CanadaVancouverCanada

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