Geologic units containing lahar

Lahar

A mudflow composed chiefly of volcaniclastic materials on the flank of a volcano.

This category is also used for volcanic mudflows.

Subtopics:
(none)

Rhode Island

Newport Group - Price Neck Formation (Late Proterozoic? or older?): Newport Group - Price Neck Formation - Fine-grained graded beds of feldspathic siltstone and sandstone, interstratified with carbonate conglomerate, and ash-flow and lapilli tuff; some units may be lahar deposits.

Washington

Landslide and mudflow deposits (Holocene): Predominantly landslide debris. Includes till-like mudflow deposits of andesitic rock fragments in clayey sand matrix in Buckley-Enumclaw area of Kind and Pierce Counties.
Miocene-Pliocene nonmarine rocks (Miocene-Pliocene): Tuffaceous and pumiceous andesitic sandstone and siltstone with interbedded conglomerate and claystone. Conglomerate beds chiefly andesitic, but also quartzitic, granitic, and basaltic; includes basalt flows locally.
Older glacial drift (Pleistocene): Till, outwash, and associated interglacial deposits; sorted and unsorted gravel, sand, silt, and clay. Includes peat beds and non-glacial sediments locally. Mostly pre-Wisconsin in age.
Pliocene nonmarine rocks (Pliocene): Conglomerate, sandstone, shale, and mudstone. Tuffaceous in part; contains alluvial fan type material locally.