Skip to Main Content
Book Chapter

Feldspar Cements

By
Published:
January 01, 2015

Abstract

Detrital feldspars most commonly undergo dissolution or alteration and replacement in subsurface settings, yet in many sandstones one also can find examples of authigenic feldspar cements. Such cements, in almost all cases, are either albite (the sodic end-member feldspar) or orthoclase (the K-spar end member)—see Chapter 2 for more details. Such feldspar cements commonly occur as thin or irregular overgrowths (not always in optical continuity with their detrital host grain) or as fills of microfractures within feldspar grains; however, they can form major pore-occluding cements in some clastic terrigenous rocks. The overgrowths can be monocrystalline or polycrystalline (sometimes even consisting of a mosaic of micron-sized rhombs—Worden and Rushton, 1992; De Ros et al., 1994). Despite their generally minor role in cementation of sandstones, the recognition of authigenic feldspars is important in understanding burial-related pore-fluid chemistry variations through time, especially because such overgrowths (K-feldspar overgrowths in particular) can be radiometrically dated using K–Ar and 40Ar/39Ar methods (e.g., Hagen et al., 2001; Mark et al., 2005 and 2008). In this regard especially, it should be noted that feldspar compositional zonation and overgrowth can be inherited from igneous, metamorphic or sedimentary source rocks, and such “overgrowths” must be carefully distinguished from authigenic cement precipitation during burial (just as recycled quartz overgrowths must be distinguished from ones produced in situ during burial).

You do not currently have access to this article.
Don't already have an account? Register

Figures & Tables

Contents

AAPG Memoir

A Color Guide to the Petrography of Sandstones, Siltstones, Shales and Associated Rocks

Dana S. Ulmer-Scholle
Dana S. Ulmer-Scholle
Search for other works by this author on:
Peter A. Scholle
Peter A. Scholle
Search for other works by this author on:
Juergen Schieber
Juergen Schieber
Search for other works by this author on:
Robert J. Raine
Robert J. Raine
Search for other works by this author on:
American Association of Petroleum Geologists
Volume
109
ISBN electronic:
9781629812731
Publication date:
January 01, 2015

GeoRef

References

Related

A comprehensive resource of eBooks for researchers in the Earth Sciences

This Feature Is Available To Subscribers Only

Sign In or Create an Account

This PDF is available to Subscribers Only

View Article Abstract & Purchase Options

For full access to this pdf, sign in to an existing account, or purchase an annual subscription.

Subscribe Now