Megaripple fields Cerro Blanco (volcano)

campo de piedra pómez megaripples

mega ripple marks formed gravel found in cerro blanco area , among extreme on earth. these formed wind-driven processes acting on local ignimbrites, including saltation of fine grains , sand during wind. ripples have amplitudes varying 0.1–2 metres (3.9 in–6 ft 6.7 in) , wavelengths of 10–30 metres (33–98 ft). coarse gravel found @ top , more fine silt in lower parts. pumice blocks found in lee surfaces of ripples, interripple areas relatively flat. unlike dunes these structures not migrate once stably formed. material these structures formed includes lithic clasts densities 2,600–3,000 kilograms per cubic metre (4,400–5,100 lb/cu yd) , pumices densities 800–1,300 kilograms per cubic metre (1,300–2,200 lb/cu yd). formation of ripples associated bedrock ridges. these ripple marks have been compared martian ripple fields.

the largest field named campo piedra pómez (centered 26°36′17.30″s 67°34′50.46″w / 26.6048056°s 67.5806833°w / -26.6048056; -67.5806833) , covers surface area of 600 square kilometres (230 sq mi), descending 3,800 metres (12,500 ft) @ la hoyada in south 3,000 metres (9,800 ft) carachipampa volcano in north. megaripples in field dark, formed older ignimbrites , lavas of 70,000-year-old piedra pómez ignimbrite. northwest of cerro blanco caldera , towards laguna purulla lies field (centered 26°39′49.97″s 67°48′55.83″w / 26.6638806°s 67.8155083°w / -26.6638806; -67.8155083) surface area of 127 square kilometres (49 sq mi), has dark colour andesitic lava , falls down 4,100 metres (13,500 ft) altitude @ la hoyada 3,700 metres (12,100 ft) @ laguna purulla. reddish-brown rosada ignimbrites , white basement material components of field. other fields 12 square kilometres (4.6 sq mi) campo purulla (centered 26°37′12.27″s 67°46′00.66″w / 26.6200750°s 67.7668500°w / -26.6200750; -67.7668500) field downslope of cerro purulla distinct albedo 13,000 years old purulla ignimbrite, , 54 square kilometres (21 sq mi) salar de incahuasi (centered 26°31′53.61″s 67°41′36.93″w / 26.5315583°s 67.6935917°w / -26.5315583; -67.6935917) field piedra pómez ignimbrite of brown colour.