Stratigraphic Unit No. 10. Interpreted deposit type: tephra fall-reworked. Thickness: 108 cm. Grain size: coarse lapilli to fine ash. Bedding: cross-beds, dippling bed, fine-ash lenses. Sorting: poorly sorted. Juvenile clast type: white pumice. Sample AT-230 to AT-232, light tan colored pumice clasts suggest a non-Crater Peak or Mount Spurr source. Remarks: pumice from dipping beds. Munsell color-wet: 10YR 4/2. Munsell color-dry: 5Y 8/1 and N5. Grain shape: angular. Age: 3650-3970 yr. B.P.
Characterization and discrimination of Holocene tephra-fall deposits, Mount Spurr volcano, Alaska
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