1. Within the center of Chuar syncline, this upper contact is a disconformity . 2. Following a disconformity the Silurian black slates are laid down 0.4 km thick. 3. The contact between the Hatakai Shale and overlying Shinumo Quartzite is a distinct, significant disconformity . 4. This is expressed by a disconformity that removed successively deeper reservoir beds to the north and west. 5. Within the Unkar Group, the contact between the Hakatai Shale and overlying Shinumo Sandstone is a distinct disconformity . 6. This disconformity is sharp and locally truncates cross-bedding and channels exhibited by sandstones in the underlying Hakatai Shale. 7. The upper contact of the Kaibab Limestone ( Harrisburg Member ) with the overlying Moenkopi Formation is an erosional unconformity and disconformity . 8. As documented by the dating of detrital zircons, this disconformity is estimated to represent a period of about 75 million years. 9. The unconformity and disconformity are inferred to represent most of Permian time ( including the Leonardian ) and part of Early Triassic time. 10. This disconformity is sharp and locally truncates cross-beds, and channel forms, within the sandstones of the underlying Hatakai Shale.
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