About This Item
- Full TextFull Text(subscription required)
- Pay-Per-View PurchasePay-Per-View
Purchase Options Explain
Share This Item
Devonian Magadi-Type Cherts in the Orcadian Basin, Scotland
Magadi-type cherts occur in lacustrine rocks of the Middle Devonian (Middle Old Red Sandstone) Orcadian Basin, Scotland. Chert nodules are replacive within organic-rich laminites, the deposits of a stratified lake. They exhibit soft-sediment deformation, including sediment injection along shrinkage fractures within the nodules. The thefts preserve stellate quartz pseudomorphs after an evaporite mineral, which may have been a sodium carbonate mineral (?trona). These are features common to other documented occurrences of Magadi-type cherts. Nodules were nucleated about vertical cracks in the host sediment and show polygonal or parallel-aligned patterns. Precipitation of the magadiite precursor occurred from alkaline groundwaters rather than in the lake water column.
Pay-Per-View Purchase Options
The article is available through a document delivery service. Explain these Purchase Options.
|Protected Document: $10|
|Internal PDF Document: $14|
|Open PDF Document: $24|