OREGON STATE UNIVERSITY

Stop 2

Stop 2 22°41'05.07"S/ 67°16'23.5"W/4846 m

23-10-10

Flow units

 

Pict 10.- Proximal Tara Ignimbrite. A 20 cm thick coarse grain sequence showing cross bedding, clasts supported (almost no fine material). This surge deposit has horizontal continuity and varies upward to a silky flow deposit and a “sillar” or vapor phase    

 Tara ignimbrite.- Outcrops related to the 3.49 Ma Tara ignimbrite were observed, a proximal one, close to the eastern scarp and a distal one, outside of the caldera edge. 

 

 

 

 

 

 

 

 

 

 

Pict 11.- Distal Tara ignimbrite underneath the Zapaleri volcano

  

Pict 12.- Distal Tara Ignimbrite over older volcanic basement three surge deposits are seen close to the base

Outside the margins of the caldera a very well exposed sequence of distal Tara ignimbrite was described (actually we were in Argentina here). On top lavas related to the Zapaleri volcano, cover this 60 m thick sequence (pict 11)