Logged to 3261.7 feet, a pallet of core boxes ready for storage

When we finished logging yesterday, we had reached a depth of 3261.7 ft.  This is 134.1 ft in a single day, it certainly helps when you have four people logging!  Over the next couple months we'll have three people logging almost every day of the week, so we should have the preliminary logging of the first phase of drilling complete by the end of July.

After logging is complete, we stack, wrap, and strap the boxes on a pallet in this trailer so they can be brought up to the drill site and be put into storage.  This stack shows the last 48 of the PQ core boxes on top of the 30 shallowest HQ boxes.  My rough estimate of the weight of each pallet is ~3000 pounds (~1360 kg).

Logged to 3127.6 feet, 177 units

Today we logged core boxes to a depth of 3127.6 ft, 209.6 ft deeper than three days ago.  So far we have identified 177 lithologic units; from the expected pahoehoe, ʻaʻa, soil, ash, cinder and intrusions to surprising dune sands, sandstones, conglomerates, and glacial till deposits.  Soon we'll be stacking and wrapping up another pallet of rock boxes to put into storage, and logging some of the most complex intrusions recovered from the entire first phase of drilling.  I'll try and post a picture of one or both of these by early next week.       

Logged to the bottom of the PQ section, 2918 feet

Today our logging efforts took us to the bottom of the PQ portion of the hole (3.375" diameter), 2918 ft.  This is 332 ft deeper than the logging depth we reached a week ago.  The logging will happen more quickly now that we're focusing on it exclusively, and everything involving the HQ core (2.625" diameter) seems a little quicker and easier.  The core box on the left is the final PQ box, it contains pahoehoe with a dense flow interior (click on the picture for a larger view of the box).

Processed to 5786 feet, the end of drilling Phase 1

Today we finished boxing up the 90 ft of core that was drilled yesterday.  This is the end of the first phase of HGRP drilling.  It's time for the drill crew to go on break, once they pack up all their equipment and leave the rig in good order.  Over the next couple months, we'll continue to log core down here at UH Hilo, and prepare for the next phase of drilling.  Blog updates will not be daily, but I will continue to update the blog regularly with project news.  We expect to have some scientists who are interested in studying the core visit us during this time, and some of the preliminary studies of the groundwater and rocks are about to begin.  

Processed to 5696 feet, secondary mineral slickensides or slickenfibres

Today we boxed rock core to a depth of 5696 ft, 70 ft deeper than yesterday.  The drillers actually drilled 90 ft of core, but not all of it was brought down to us because of some of the activity related to wrapping up the drilling.  Tonight will be the end of the first phase of drilling this hole, I'll post the stopping depth tomorrow.  Meanwhile, here's another picture of a new and interesting feature we saw in the core today:

Here Bryan is holding a piece of core (diameter 2.625") that has green to white mineralizations on a fracture surface.  These minerals look just like the majority of the secondary material we're seeing in core vesicles and fractures, except that here they're striated in one direction.  Considering how much of this secondary mineralization we've seen in the deeper reaches of the hole, it's surprising that we haven't seen this kind of feature until today (when we saw two examples of this).  The composition of this material is certainly different from the slickensides/slickenfibres we saw shallower in the hole, but the process that formed all of them is probably the same.

Processed to 5626 feet, another sedimentary unit

Today we boxed up rock core to a depth of 5626 ft, 100 ft deeper than yesterday.  At this depth, if the rock drills well, this is about the maximum possible recovery in a single day. 

Above is a photo of another sedimentary unit, lately the drilling has recovered one interval of sedimentary rock each day.  This unit contains two large clasts in a finer-grained matrix at its top and middle portions, and then fine sediment at its base that shows bedding and cross bedding.  Note the presence of a variety of clast types in this unit, as well as green and white secondary materials. 

Processed to 5526 feet, logged to 2586 feet

A quick update on drilling and logging progress:  Today we boxed rock core to a depth of 5526 ft, 70 ft deeper than yesterday.  We saw more ʻaʻa today than usual, in fact it was the first time in a few days that we've seen ʻaʻa at all. 

Each day when we finish boxing up the newly drilled core, we head over to the rock lab and log the core's features into the database.  As of the time of this blog post, we've logged to a depth of 2586 ft; 86 ft deeper than a few days ago.  Soon the first hole of the project will be finished and we'll devote all of our workdays to completing the logging of all the rock recovered from that hole.

Processed to 5456 feet, more sediment

Today we boxed rock core to 5456 ft, 80 ft deeper than yesterday.  One of the really interesting sections of rock that we saw is the sediment shown in the photos below:


The photo on the left shows the entire interval of sediment (1.4 ft thick), while the photo on the right is a close-up view of the upper portion of this interval.  Note the bedding of the sediment, and the abundance of green (altered) material that is helping cement the sediment together.  The grain sizes of the sediments range from gravel to silt, but there is no particular gradation in sediment size with depth.  Also note that in the upper portion of this sediment interval there are pahoehoe flow fragments (center of right photo), which presumably were eroded from their original location and ended up in the body of water where the sediments were deposited.

Processed to 5376 feet, extremely coherent rock

Today we boxed up another 100 ft of rock core, to a depth of 5376 ft.  Below is a picture of the rock that was drilled last night, which we processed this morning.  When fractures are this rare, the rock generally can be drilled more easily to produce full runs and it is also easier to process and interpret.

Note: Each tray is 6 ft in length, with the top ends painted.  There are pieces of circular foam at each end and a cover on each tray during transport.  Wooden blocks with the bottom depth of each run written on them are placed at the end of each run.  A full run is 10 feet in length.  With the foam and wood blocks and fractured rock, one run nearly or completely fills two trays.

Processed to 5276 feet, logged to 2500 feet

Today we boxed rock core to a depth of 5276 ft, 70 ft deeper than yesterday.  The slightly lower amount of rock drilled was due to an upgrade of a few parts on the drill rig, which will help the crew save time in the long run. 

Down here at UH Hilo, less core means more time we spend logging.  We've now logged just past 2500 ft.  Sorry today is just another text update, I promise a picture tomorrow.

Processed to 5206 feet

Just a quick text update on the drilling progress: Today we processed another 80 ft to a depth of 5206 ft.  The drillers seem to have this recovery rate dialed in, hitting it on the dot nearly every day.  The bit they're using has lasted over 1000 ft so far, and could finish this hole.  Today was rainy and not great for pictures, tomorrow I'll try and post a photo of some of the interesting rock we've been seeing.

Processed to 5126 feet, moved more boxes of rocks around

Just a quick update today on our progress.  This morning we boxed rock core to a depth of 5126 ft, 80 ft deeper than yesterday.  After that, it was time to move all the boxes we've logged out of the rock lab, onto a pallet, and into storage.  Finally, we filled the lab with new boxes to log and shifted other boxes into the drying area. 

Above, Mike uses the rock saw to cut a particularly long, unbroken piece of rock core into two-foot sections that will fit in the core box. 

Processed to 5046 feet, logged to 2444.3 feet, sandstone unit

Today we processed rock core to a depth of 5046 ft, 160 ft deeper than two days ago.  The drilling is in the home stretch of this first hole now, as we're fast approaching the 6000-6500 ft target depth.  At this rate, we could complete the first hole in 2-3 more weeks.  Each afternoon we continue to log the rocks, and by the end of today we've logged some interesting units to a depth of 2444.3 ft.  Below is a picture of the first sandstone unit we just recently logged (field of view is ~3 cm across)

This sandstone is made up of olivine grains (green), lithic fragments of basalt (black or gray), hematite (rusty orange), and a variety of other white to clear secondary minerals like calcite and zeolites produced by physical and chemical weathering of the original rock.  The sand has been compacted by the weight of over 2000 ft of rock resting on top of it, and weakly cemented together by secondary mineral growth.  The average grain size and degree of sorting indicate that this sand is fluvial in origin (deposited by a stream).  However, the angularity of the grains and lack of bedding indicate such a stream was probably ephemeral and may have washed the sand downslope to its final resting point in as little as one heavy rain event. 

Processed to 4886 feet, flaky green secondary mineralization

Today we boxed rock core to a depth of 4886 ft, 170 ft deeper than two days ago.  We saw one intrusion that was only a couple feet thick, and overall less secondary minerals than we've become used to seeing.  However, one fracture in particular showed quite a deposit (photo shows about eight inches from top to bottom):

 

At the time of the photo, this material was still wet and showed this striking green color.  When it dries however, it becomes a pale green and doesn't contrast as well with the surrounding rock.

Processed to 4716 feet, logged to 2322.6 feet

Today we processed 80 more feet of rock core, to a depth of 4716 ft.  The rock continues to hold together extremely well, and the secondary minerals aren't causing as many problems with the drilling as before.  We also made significant progress logging this afternoon, interpreting rock units to a depth of 2322.6 ft.

Processed to 4636 feet, elongate black olivine and more secondary mineralizations in vesicles

Today we boxed rock core to a depth of 4636.0 ft, 150.5 ft deeper than two days ago.  The rock continues to hold together extremely well, making our job a bit easier.  Here are a couple images of the features we've been seeing lately in the core:

Both images are of the same rock, the one on the left is core that has been dried while the one on the right is still wet.  The greenish hue of many of the secondary vesicle fillings is more evident in the wet core, while the elongate, black olivine is easier to see in the dry rock.  Note that the green material is concentrated toward the bottom of the vesicles, and it grades upward to white.  We have even seen layers of fill in some vesicles, with a sharp horizon mid-vesicle where the secondary mineralization changes from green to white material.  As for the elongate black olivine, we've been seeing extensive amounts of it throughout many units, so it isn't correlated with rapid cooling near unit contacts like the elongate olivine observed shallower in the hole.  I suspect that this olivine is black from the low-temperature alteration that is filling the vesicles, rather than the typical baking that can turn olivine black.

Processed to 4485.5 feet, a closeup of phillipsite

Today we boxed rock core to a depth of 4485.5 ft, 89.5 ft deeper than yesterday.  There was one intrusion among the units we processed, and lots of vesicles filled partially or entirely with secondary minerals.  Below is an example of a common zeolite mineral we've been seeing lining vesicles in the core, it's white and called phillipsite:

This image is only about one inch from top to bottom, and the phillipsite looks like small spheres lining the vesicles.  In fact, phillipsite does not make spheres at all, but rather many thin fibers grow radially outward from a central nucleation point.  This gives the impression of a sphere unless you use magnification to view the mineral or find a large enough sample to see the fibers with the naked eye.  Phillipsite and the other zeolites we're currently seeing in the core all incorporate water into their structure, indicating chemical interaction between the rock and groundwater caused the formation of these minerals.

Processed to 4396 feet, slow drilling rock

Today we boxed rock core to a depth of 4396 ft, 79 ft deeper than yesterday.  Some of the lava units that we've been seeing lately are particularly rich in secondary zeolite minerals and smectite clays.  At least one of these secondary alteration products has a soapy, slippery consistency that is making it difficult for the drill bit to bite into and cut the rock.  Drilling units rich in this material can take two to three times as long as those without.  Here is a picture of a typical one of these units:

Note that the unit is also rich in olivine (brown from alteration, with a bit of green unaltered olivine visible in the center of some grains if you click on the photo and view the larger version).  The core is quite unfractured, implying that the secondary vesicle fill may actually be adding strength and coherency to the rock.  Not all the lava units look like this, but these type of units are encountered nearly every drilling shift at some point.    

Processed to 4317 feet

Just a quick text update today to mention that we boxed rock core to a depth of 4317 ft, 101 ft deeper than yesterday.  We were able to finish that just after lunch, and logged core boxes for the rest of the afternoon.  Tomorrow I promise to post a picture of some of the interesting rock we've been seeing.

Processed to 4216 feet, least fractured core of the project

Today we boxed rock core to a depth of 4216 ft, 250 ft deeper than the last blog post.  I haven't been able to update the blog until today, but we've continued to process and log core over the past few days.  I have some interesting photos of the rock to share, here are a couple taken earlier today:

Above are the core trays delivered late this morning, which are some of the least fractured runs of the entire project.  The third tray from the left contains an unbroken length of core that our 6'-tall manager stood next to for scale.  Stay tuned for further photo updates that show these rocks in greater detail.