The nature and provenance of Golestan loess deposits in northeast Iran
Article first published online: 20 NOV 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Volume 48, Issue 6, pages 646–660, November/December 2013
How to Cite
Asadi, S., Moore, F. and Keshavarzi, B. (2013), The nature and provenance of Golestan loess deposits in northeast Iran. Geol. J., 48: 646–660. doi: 10.1002/gj.2466
- Issue published online: 5 NOV 2013
- Article first published online: 20 NOV 2012
- loess deposits;
- felsic source rock;
- Chemical Index of Alteration (CIA);
- Golestan province;
Mineralogical, textural, geochemical, and weathering characteristics of loess deposits in Golestan province of Iran suggest that they are mostly derived from felsic igneous rocks and are related to Quaternary palaeoclimate. Whole-rock analyses indicate heavy minerals such as zircon, tourmaline and phyllosillicate minerals (e.g. muscovite, chlorite, illite) exert a significant control on the chemical composition. The loess samples display uniform chemical composition, indicative of similar alteration history. Chemical index of alteration suggests a weak to moderate degree of weathering in a felsic source area. Scanning electron micrographs of quartz grains reveal abundant silt-sized quartz particles, a result of glacial grinding during the Late Pleistocene in Central Asia. Subsequently, these silt particles were transported from Central Asia to their depositional site by wind and paraglacial processes. Local topography of northeast Iran (Alborz Mountains) acted as a major barrier, entrapping the airborne particles on the plains of Golestan province. Copyright © 2012 John Wiley & Sons, Ltd.