@TieDyeSciGuy@sam_learner Not sure if it is connected to Lake Malawi to the south, but I will take a guess that it is from Lake Tanganyka, to Lake Kivu, connected to smaller lakes to the White Nile, confluence with Blue Nile to the Mediterranean.
Mountains rise and fall on geologic timescales, but much of the process occurs thru episodic events like this mountain side mass wasting. Beautiful yet terrifying.
@WVURockDoc @IAVCEI_official@SmithsonianGVP Harrat al Birk is not well-studied, but a fairly nice description is in USGS-OF-03-93 by Bob Coleman et al. There is a fair info on the post-Miocene basement rocks, but no actual comment on thickness. My guess: a max of 200 m, but that is only a guess.
@subglacial@rockhardIES@visir_is I tend to agree with Adam Swindell's comments. It seems to be only the eruption rate that is periodic, with little evidence that it correlates with corresponding periodicity in the magma supply rate. However, a chemical change might well indicate otherwise.
@lisgallant I love the draped agglutinate drainback features here, and the NPS guide of the Mauna Ulu eruption is a well-written summary with personal experiences of a spectacular eruption from Don Swanson, Wendell Duffield, and Jeffery Judd.
@mt_dorsey @CinTyLee1 Flattened shear (?) fabric of the dike is not present in the interior 1/3 portion of the dike. Shearing may have been present in chilled borders while flow during dike pentetration of the interior was little effected.
@kurtschwehr @RockIceandSnow Track changes are one thing, but imagine writing four papers with a colleague in Saudi Arabia before email. We sent long letters of comments back and forth with turnaround times of about 2.5 weeks. It took 3 yrs of correspondence, but somehow we go it done!
This is an Archean peridotite from the Grib #diamond mine. How many more super old peridotites are there at Grib? Tune in on Friday 18 June (13:00 South Africa time) to find out ๐๐๐ฉโ๐ป
This IS a nice map, not only for en echelon pattern of MOR segments, but also for systematic variations in chemistry away from central rift, from MORB to EMORB to alkali basalt, as expected. Great to see this!
Some of the best gas segregation pipes around. Resistance to erosion is from vapor-phase crystallization of quartz/alk feld that binds the coarser pyroclasts, with smaller vitric ash depleted by gas escape. Beautiful example.