Pleistocene Glaciation in the Pacific Northwest

I. Ice Ages A prolonged _______________ in Earth’s history in which global climate is significantly _________ than the mean with significant portions of surface covered by _______________. most ice ages lasted ____________________ ice ages of geologic past  _____________

I. Ice Ages Major Ice Ages in the geologic past Precambrian  Paleozoic  Mesozoic  Cenozoic 

Global “Ice Ages” through time

I. Ice Ages Cenozoic ~30 Ma (Oligocene)  first ice sheets in __________________ 12-10 Ma  _________________________ ~2.0 Ma  ___________________________

I. Ice Ages B. Causes Ice Ages Continental drift & tectonic uplifts Changes in atmospheric compositions  GHG’s Long term volcanism Sun-Earth orbital variations Changes in oceanic circulation Solar output

II. Glaciation Basics Types of glaciers 1. Alpine (mountain glaciers) 2. Continental Ice Sheets

II. Glaciation Basics B. Landforms

II. Glaciation Basics Erosional 2. Depositional

III. Pleistocene Glaciation

II. Pleistocene Glaciation A. Intro to the Pleistocene most recent glaciation  several glacial periods  globally  North America, northern Europe, northern Asia, Antarctica Extensive ____________________________

Pleistocene Ice Age: 30% of Earth’s surface covered

II. Pleistocene Glaciation B. Pleistocene North America Canada  ___________________________ New England & Great Lakes Northern Tier states Pacific Northwest  ____________________ Mountainous west

II. Pleistocene Glaciation C. Glacial Intervals Glacials = Interglacials =

III. Pleistocene Pacific Northwest Puget Lobe

III. Pleistocene Pacific Northwest

III. Pleistocene Pacific Northwest B. Okanogan Lobe & Central Washington

III. Pleistocene Pacific Northwest C. Colville, Pend Oreille, Purcell Lobes