Title: Authigenic albite in the Pendleside Formation (Dinantian) of northern England
Abstract: Summary Authigenic albite occurring as euhedral overgrowths up to 400 μm in size is a characteristic feature of the Pendleside Limestone in the Craven Basin of northern England. The albite is very pure, low-albite in keeping with other authigenic albites in carbonate rocks. The detrital cores of the albites are angular plagioclase grains of approximately An 20 composition which are sometimes altered to kaolinite. The albite crystals with their detrital cores are frequently concentrated in discrete laminae, suggesting that the plagioclase cores may have been supplied by a basic volcanogenic source. This view is supported by geochemical studies of limestones which reveal significant correlation between K–Na, Na–Al and K–Al. Interstitial alteration of detrital components, in particular the reaction intermediate plagioclase → kaolinite + albite, was primarily responsible for albite authigenesis. The initial products of this reaction probably included smectite which fixed Mg 2+ in the decomposing volcanic grains. Subsequent alteration of the smectite resulted in the formation of small microdolomite inclusions which are commonly seen in the authigenic albites. An equilibrium model in terms of Na + /H 4 ratios and H 4 SiO 4 activity is proposed for the silicate assemblages in the Pendleside Formation.
Publication Year: 1982
Publication Date: 1982-07-01
Language: en
Type: article
Indexed In: ['crossref']
Access and Citation
Cited By Count: 5
AI Researcher Chatbot
Get quick answers to your questions about the article from our AI researcher chatbot