Three more beautiful cores arrived on deck on Thursday, the last one from a bottom depth of 261.5 meters. Now the drillers have a little bit longer break for weekend, due to italian holidays. A good chance for the science team on site to catch up with some core logging.
... and the core production keeps going! Another set of eigth cores today, and we arrived to a bottom depth of 252 meters. Fresh metagabbros with big garnet porphyroblasts, garnet-rich layers and mylonites are just some of the nice structures revealed by the cores of the day. Meanwhile an enthusiastic visit from the representatives of a nearby local company kepts some of the divers busy with some outreach.
After another good day with 4 intact cores on deck, PQ rods had to be pulled out and the drill bit has been thanked for its long lasting and efficient service. Meanwhile the magnetic susceptibility logger has been repaired and the drilling site has been visited by the Swiss Geophysical Commission.
Another efficient day today: crossing the 200 meters depth and getting eight intact cores on deck. Nice garnet-rich mafic lithologies, often crossed by sealed fractures and shear zones with various mineralogy. Quite some work for the new science crew which arrived yesterday, together with the first snow of the year!
After a bit "frightening" fragmented zone, with interesting cavities, breccia and vein-filling minerals, the cores continued in the lithology we got used to in the past days: metagabbro, with cm to dm scale variability, and many pseudotachylyte/cataclasite zones. Another productive day, with 21 m of new cores, and current hole bottom at 184 m depth. Rain, but in exchange not that cold
A very efficient day in Megolo di Mezzo: 8 cores for a total of 24 metres of cores, mostly metagabbros with some additional nice features. The on-site density estimator had been set up: metapelites at 2.90 and metagabbros at 3.29 g/cm³, is this the Moho?
After a series of clarifications on the actual depth, a productive afternoon brought us many cores, less and less fractures, and gabbro: the last core was broken only in one place! Fluid sampling from early morning to afternoon, and a third microbiology sample was also taken. If every drilling day could be this productive...
Rock consistency varies more rapidly than the rate at which drillers can adapt the drilling bit type. As a result, only 6 meters of cores today, we are past another fragmented zone at ca. 123 m depth. Nevertheless, the rocks and the fractures remain very interesting. In the waiting times we could catch up with some paperwork.
Today the new science crew arrived and had quite a productive day, after we have crossed a depth of 100 m over the weekend. Drilling now is at 115 m, a small fractured zone was crossed and five more cores arrived on deck.
Even so a minor issue with the drill rig slowed down the work on site, we arrived at 97.3 m today and microbiological sampling started! Interesting cores rich of metamorphic and tectonic structures keep arriving on deck.
Nice and productive day, with 18 m of mostly intact cores showing a variety of lithologies and structures. Bottom depth is now 94 m. Busy day but quite a satisfaction for drillers and geologists on site!
The cement is dry and drilling into the much-awaited bedrock could begin. Two days of drilling got us to a depth of 75 meters. Many of the retrieved cores are considerably fractured, but do contain a wide variety of structures that will certainly be of interest to the DIVE scientists. The microbiology team arrived, ready to work on the most suitable samples for the search for deep life.
After tasting the bedrock at a depth of 57.8 meters, a new borehole had to be drilled to adjust for an optimal inclination. Two days of destructive drilling were enough to be back on track and the corrected borehole has already been secured with cement. While waiting the curing, our on-site scientific team is actively analyzing the initial crystalline cores retrieved at the interface between the alluvial deposits and bedrock.
After getting to a depth of 48 m into the sedimentary cover, some difficulties aroused due the presence of very heterogranular sediments. With some changes of drill bits and a temporary use of polymer we got the first rock cores on deck today!
Few more days of drilling into sediments led to a depth of 46.1 meters. Cores on deck were mostly homogeneous silt and fine sand, but the last ones included some angular rock fragments suggesting we might not be far from the bedrock. Meanwhile the preparation of the containers and tent for the science team had been completed and the site is ready to host the first team arriving next week.
Containers for the science team finally arrived and the preparation is proceeding, despite quite a rainy day. Equipment for online gas analyses also arrived and is ready to be installed. Meanwhile, the sedimentary cover has not yet been crossed.
Drilling through the sedimentary cover started today at 5071_1_A (DT-1a; Megolo) and the first 3 m of sediments were recovered. While waiting for the drill bit to touch the crystalline basement and the first rock core to be on deck, DIVE site managers are already on site for the preparation of scientific activities. Other members of the science team are eager to leave for Megolo and ready to work on the so awaited cores!
All cores of DIVE borehole 1B are now in the national core repository for continental drill cores in Berlin-Spandau (GER) where a preliminary sampling party for PhD and post-doc research tightly related to DIVE has taken place recently. After some initial hurdles, our routine could be established: XRF and MSCL scans were performed on all cores that have subsequently been sampled. The smallest sample taken was ca. 250 g, the largest more than 9 kg (!). It will be returned. We look forward to the forthcoming results.
This is the end! The end of on-site activities in welcoming Ornavasso, and the upper end of the borehole on the photo: it is now sealed for a few weeks until a longer-term solution is installed. HUGE THANKS to everyone who has worked and helped on site!!! See you in 2023.
DIVE has completed logging and cleared the science part of site 5071_1B by Sunday December 18th. It then required a local heavyweight roadshow to pick up a single GFZ-container today. The entertainment was free of charge for innocent observers. The borehole will be properly sealed for the coming weeks, until site restoration early next year.
Snowy logging today. Succesful OTV in the bottom part of the hole, the gamma tool did not work properly. A few more days to go, VSP is next on the program.
Logging and blogging. These are the remaining two activities at site 5071_1_B. The borehole is now fully accessible and logging has started, with the plan to finish all the program by Sunday, with active participation of ICDP-OSG, MU Leoben, Uni Lausanne, and several other university partners.
Today the DIVE drilling target 5071_1_B in Ornavasso has finished the drilling activities, and the borehole has reached 578.7 metres depth below surface. The final images of the day show the bottom of the last core, ongoing packing, and the great finisher team on site!
After the ultimate reinsertion of rods, the last run of efforts are ongoing to drill, currently at 575 m depth. Brittle deformations seem to draw a big arrow on this particular core, showing large sulphide crystals inside. Preparation for the winter hibernation continued while snow started to cover the site.
From about 560 m depth, the borehole still kindly provides us quite some rock-type variability! At the surface, the seismics while drilling experiment is nearing its end, preparation for final logging has started, and temperatures plummeted below freezing point.
Most of the fluid that came out over the logging week-end has now been used again and reinjected to the hole during drilling, reaching 549.3 m depth by the end of the day. An important decision has been taken: due to the structural context, it has been decided that drilling hole 5051_1_B will be stopped before the end of this week. The results are satisfactory and no major progress can be expected from here on.
A new tramway line to the drilling site? No, just fixing the wireline winch. The 200th core was extracted, and some euhedral sulphide crystals found inside a fracture. Current borehole depth is 522.4 m.
New week, new crews: while re-insertion of the rods into the borehole began, the joint interpretation of logs and core scans has been completed. A strategy meeting is scheduled for tomorrow. In the meanwhile, 25 interested high-school students visited the site and benefited from a special lecture by Andrew Greenwood (see photo).
A second optical televiewer logging session today has revealed a bit more of the borehole walls than on Thursday, the images are being picked and merged with previous datasets. We also sampled the fluids under (but separately from) the persisting rain, and collected a good amount of the rising gas bubbles (see photo). Drilling should resume tomorrow.
A quiet day on site, spent mostly with data processing and analysis, storing the outflowing fluid, and tidying the compound. All data seem to point to steeply dipping foliation, a joint interpretation is in preparation to put everything in perspective. On this note, the photo shows our DT-1b site from – 200 m depth.
A beautiful, sunny December morning has seen a lot of pipes come out of the hole in preparation for logging. As the Sun has set behind the mountains at 13h, the logging lab has started to be installed. By the late evening a successful optical and acoustic televiewer logging has nicely imaged the bottom 60 m, respectively 250 m, of the borehole. Credits go to Andrew, Ludovic, good preparation, and our new winch.
The crossing of the 500 m depth level has been celebrated in the early afternoon, when the 6th core out of today's 7 has seen light. The pulling ability of the rig is now fully functional. The current bottom depth is 504.3 m, drilling resumes on Monday. Until then, a geophysical logging program is on the agenda, to evaluate the position of the borehole with respect to the geological structure more precisely.
Efforts continued overnight and all day to fix the presumably last bug of the new rig. When it drills, cores are produced very quickly, but pulling remains irregular. Six cores produced in the past 24 hours, reaching 483 m depth. Today has seen several visitors on site, in particular the CEO and chief geologist of the drilling company, all in a positive atmosphere.
The day plan included a rapid change of rigs, which ended up taking the whole day. Nevertheless, the new, strong and blue PSM-16GT rig became operational in the late evening, and a night-shift crew left from the side of their beds to pick up work and hopefully new cores, restarting from 465.4 m depth.
After loss of circulation and sudden stop of rods in the morning, the drilling could continue and went beyond 450 metre depth. The evening has brought full-house attendance at the local town hall meeting, in the cinema/theatre room, with 1.5 hours of presentations followed by a Q&A session.
Another drill bit got worn down and required changing, see the very clear photo comparing the old and new bits. Changeover takes quite some time at 438.8 m depth. We hope the new bit will last at least as long as the previous ones.
After 7 weeks of drilling, core-box number 100 was filled with cores, and the hole reached 429.5 m depth. Large leucocratic layers were observable on most cores. The site is now fully restored after yesterday's storm. A public event in the village Ornavasso that is hosting the drill site will take place Friday evening.
Soon after breaking the 400-metre-depth line this morning, wind gusts attacked the drillsite and overturned every tent and gazebo, dismantled the fences and more. Thanks to a major effort of the on-site team, everything was reconstructed by the evening. In the meanwhile the drillers have produced at least 12 metres of fresh core, quality-wise similar to yesterday.
The week-end has seen the arrival of the microbiology microscope, verified by looking at the tracer. The hunt for microbial activity traces can start for good! Today coring is back on track, with a beautiful, straight, continuous 3-m-long HQ core extracted from 390 m depth, sampling a sharp metapelite–amphibolite contact.
Binary file (standard input) matches Today's picture, ""The Lost Catcher and the Old Bit"", turned out to be a shorter story than ""The Old Man and the Sea"", but for DIVE it was still an award-winning event as drilling could then continue and reach 372.4 m depth.
Not every day brings good surprises. Today the core catcher broke (see on the left of the photo). Most of it could be pulled out, but a piece remained at the bottom of the hole (similar to what is highlighted with the arrow on the right). Hopefully it will be still attached to the piece of core lost during the recovery.
At about 350 m current depth, and 20-25 km paleo-depth, surprises come in the form of cavities like this finger-size, crystal-padded niche. Microbes may like to live here! (Spoiler
We past 300 m depth with a borehole deviation of less than 1.5° from vertical, which is well within the wished tolerance. After a logging session over the weekend, we resumed drilling and changed from PQ to HQ diameter. Using HQ, we collected 15 m of cores in a single day shift. The foliation we observe now is at an angle from vertical.
Today the 300 m line was passed still using PQ. This will allow the broadband seismometer to sit there comfortable in the future. During the weekend logging will now take place before we resume drilling using a smaller, HQ, diameter. -we'll know better after this week-end's logging where we are structurally, indeed in the recent days many cores showed axis parallel foliation, which we don't want to see for too long -after the logging, drilling will continue with HQ and hopefully speed up a bit -there have been interesting mineralogical news, graphite, some sulphides, and very nice ductile deformation features
No drilling shifts on Saturday night or Sunday but we have plotted the first 180m of Magnetic Susceptibility data recorded at 10cm intervals along the core. After (core-diameter) volumetric corrections we can clearly see some lithologic changes and localised anomalies.
Core bit n.7 is performing well with another great 24hrs of drilling and 24m of core recovered. Now at core number 110. We also have intersected graphite.
Currently passed 160 m with trials of different drill bits continuing. The softer matrix of the bits exposes new diamonds more regularly, but at the expense of higher bit wear.A fine balance needs to be found. Photo of Bit # 3
A bigger rig has arrived. Il piccolo carro di perforazione has left site and il medio carro di perforazione has arrived. A new diamond drill bit will be put the test in the hope of getting a better RoP in this very hard rock, and we also cased off the upper section of the borehole 3m during the change over. Fingers crossed no more obstacles ahead.
We have reached our first 100m with the best production day to date. And, the bigger rig arrives tomorrow with more crew and double shifts starting soon.
Another week of drilling and a new set of young geologist on site to help. We are itching to break the first 100m, but things are still slow. Trial and error with different drill bits to try and beet this extremely hard, but beautiful, rock,continues.
