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.
