Chemical weathering associated with tafoni at Papago Park, Central Arizona

Papago Park, Arizona, is a pediment-inselberg complex that hosts a variety of well developed tafoni and alveolar weathering forms. The purpose of this paper is to analyse the nature of chemical weathering associated with the tafoni using backscatter electron microscopy (BSE) and quantitative wavelen gth dispersive X-ray analysis (WDS). Calcium-rich and iron-rich coatings oc cur on the outer shells of the tafoni. Calcium carbonate precipitation with in mineral microfractures occurs on the underside of the tafoni. Chemical w eathering of primary mineral grains provides a source of material found in the coatings. The WDS analyses show a near-complete lack of salt-forming el ements. Copyright (C) 1999 John Wiley & Sons, Ltd.