2011 Schreibers Meadow cinder cone, lava, and tephra

The Schreibers Meadow cinder cone, south flank of Mount Baker, seen from the north. DT photo. Click to enlarge.

September 24 and October 1, 2011. MBVRC twice offered a 2 mile round trip guided geology hike to examine the 9500-year-old cinder cone in Schreibers Meadow on Mount Baker’s south flank. The trip sold out the first time, so we offered it again, and it sold out again- and then some! In additon to the cinder cone hike, the excursion stopped at a road cut about 1km northeast of the cone to examine scoriaceous tephra that fell out of the eruption cloud, and a quarried section of the lava that flowed out of the cone after the tephra eruption had ended.

Scoriaceou lapilli ('cinders') that fell out of the eruption plume from the Schreibers cinder cone. Photo by Neil Gilham.

The bushwack up to the cinder cone rim. Click to enlarge.

Between the two trips, there were 34 participants, who ranged from 15 to ‘a certain age’ (that means well beyond retirement age; we’ll leave it at that). There were a couple of geology undergraduates (UW and                      in Victoria, BC) and two professional geologists. All the others were interested members of the public with little to only slight background in geology. That was the intent of this trip, though, to provide an opportunity for the general public to experience nearby volcanic geology and learn something about volcanism in general. They paid to go on the excursions. Proceeds accumulate in MBVRC’s research grant fund.

The first trip enjoyed dry weather, with views of Mount Baker, and a mostly dry hike through huckleberry brush to the cinder cone. Participants on the October trip had to deal with a sporadic thin drizzle, which made the cross-country hike to the forested cone damp and slippery. After ascending a trail-less 30 degree slope for about 100 feet to the crater rim, we descended about 50 feet to the curious pair of ponds lying in the crater. We speculated on why a cone made of such a  porous material as loose basalt gravel-sized fragments falling out of the air would hold water. Several ideas were broached, but so far the leading contender seems to be the accumulation of organic forest litter in the crater as the cone became vegetated. The fine grained, slowly rotting organics may have plugged up the  voids between tephra lapilli allowing rainwater and melting snow to gradually accumulate.

One of the pionds in the crater of the Schreibers Meadow cinder cone. Photo by Bill Waight.

Today, soggy moss and grass forms most of the shore of the little lakes. Another highlight of the hike was the blueberry-rich piles of bear scat- they had certainly high-tailed it away as our group thrashed through the brush to and from the volcanic cone.

At the lava flow quarry, we could see vesicles, some stretched by movement of the basalt lava, the blocky flow surface. With the aid of a hand lens, folks could see the larger crystals in the gray rock of the lava flow: clear and glassy plagioclase, greenish-black clinopyroxene, honey brown orthopyroxene, and a few coke-bottle green grains of olivine.

Getting a close view of the Sulphur Creek lava. Photo by Kitty King.

These trips were a success for MBVRC and provided a unique outdoors volcano education for the participants. The popular excursion will certainly be offered again in 2012. Subscribe to this website to have the earliest opportunity to register for the next time it is offered (summer of 2012).

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