Wednesday, May 20, 2015

Geo 1095: May 19, Day 869: Channel Conveyor?

If Anne hadn't pointed these channels on our trip the previous summer, I would've either not noticed them, or I would've assumed they were probably lava gutters (here are a couple of examples of lava gutters). However, these may actually be water carved channels, or possibly water-modified lava gutters. I'm relying on a short discussion a couple of years ago, and I'm not sure how clearly I remember it. But look at how verdant the vegetation is here! There are rhododendrons in the upper left, a young cedar on the center left, and another in the lower right. This does not look at all like an extremely young lava flow; it looks more like a late-stage second growth conifer forest. The general idea, as I understand it, is that rare burst floods from the slopes above this glacially carved valley may be responsible for carving or modifying channels like this one, and provide a potential explanation for how portions of the Collier Cone Flow in this area have been so rapidly reforested. Such floods may have provided sediment and plant debris, allowing a jump start to soil formation. Otherwise, the slow breakdown and colonization of fresh lava would taken several times as long. Similar flows with similar climatic and environmental conditions nearby are nowhere near as heavily vegetated.  As I pointed out in the previous post, the distribution of heavily tree covered areas on this flow is patchy. Here, close to this channel, we're in lush, mature forest.

Photo unmodified. October 9, 2014. FlashEarth location.

No comments: