Description: From Fierstein (2007): "From the vent at an elevation of 2,010 m, two of the flows extend 6 km to termini as low as 300-350 m in Martin Creek; we call these the "south lobes". One of the youngest flows bifurcates to the northeast; we call this the "Y-flow". The rim of the ice-filled crater on the East Summit is strewn with coarse scoriae and dense glassy blocks of phreatomagmatic ejecta, deposited upon the surfaces of thin lava flows exposed locally. Compositional data for one such ejecta block is used here to represent the "East Summit" in the following correlations."
"Considerable overlap in the microprobe data between the different East Mageik lavas and tephras (Fig. 23 [in original text]) preclude firm correlations, but we tentatively suggest that the…higher MgO of magnetite correlates the upper pale tan ash with the East Mageik Summit (∼2,600 14C years B.P.)."
"Separated from the mica-bearing ash (K-2500M) by another 15.5 cm of dark peaty soil is a 1-cm layer of pale tan ash (K-2500L). This ash is preserved farther upstream in Angle Creek (K-2498; Fig. 2 [in original text]) and in two additional key sections (Fig. 3 [in original text]), including atop the Martin coulees and in Mageik Creek (K-2197), where it is as much as 5 cm thick, 10 km ESE of the East Mageik crater (Fig. 2 [in original text]). These thicknesses suggest the tephra came from East Mageik, which is consistent with glass data that shows complete overlap with the two older Mageik ash layers (the lower grey ash and ODLF) represented in this section by K-2500 J and H (Fig. 13 [in original text]). Because sample K-2500L is halfway between K-2500 M and J (which brackets its age in this section between 2,310 and 3,355 14C year B.P.), our best estimate for deposition of the upper pale tan ash layer is ∼2,600-2,900 14C year B.P., favoring the younger extreme."