The photo on the left shows an intrusive contact with an olivine-rich lava flow on top and a fracture surface of the intrusion exposed below the contact. The photo on the right shows the bottom contact of that same intrusion over that same lava flow, with a different fracture surface exposed again. The psychedelic colors you see are probably all within the smectite clay mineral family, formed by low-temperature alteration of the intrusive rock as it was chemically weathered by groundwater. This four-foot-thick unit is the first intrusion we've seen for hundreds of feet, but it was well worth the wait!
Beautiful stuff. Keep up the great posts.
ReplyDeleteThanks for the support! Always nice to get approval from an HSDP original. Stop by some time when you're in town if you want to see some rocks in person.
DeleteWill do. When is DT putting tools down hole? Core box photo reminds me of some of the stuff we saw at HSDP. That `A`a doesn't look fun to drill through...
ReplyDeleteMy estimate is that he could be doing water sampling in a week or so, it depends on when we reach 3000' and conditions at that depth. So far no one has come forward to do downhole geophysical surveys, so it would only be water sampling tools. As for the ʻaʻa, if you're referring to some of the shallow and nearly nonvesicular rock in the shallow portion of the hole, that was great drilling compared to the loose material in between the flows that would eat up bits and cave into the hole almost constantly.
DeleteThat rubble between flows is a killer. I remember it eating up a lot of equipment. The massive sections of `a`a are really cool. Is DT's wireline still working or is he planning on sampling with the drill string?
DeleteHe will be sampling using the current rig's wireline, I haven't seen the exact tools he'll be using though.
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