Geology Colloquium Thursday, April 12th, Dr. Mark Abbot, Univ. of Pitt The Holocene Environmental History of the Central Andes from Lakes and Glaciers 4:00 pm in Room 310 White Hall. Refreshments will be available at 3:45 PM. Everybody is welcome! Glacial Deposits • Lodgement Till • Ablation Till • Flow Till Form a Committee and see what you get… Till Genesis: Till Work Group 1977-82 Report (Dreimanis) Till Subglacial Till Supraglacial Till Sub- Melt- aqueous & Out & Subaerial Sublim Mass- ation Movement Till Till (Flow Till) Melt-Out Till Melt-Out Lodgement Till Deformation Till Mass-Movement Till Mass-Movement Key: Subaquatic Till Melt-Out Ortho- Till Allo-Till 1 Till - a Type of Glacial Sediment Basal till from the last major glaciation ~ 18,000 years ago; Loch Torridon, Scotland. M. J. Hambrey photo. http://www.swisseduc.ch/glaciers/glossary/till-en.html Glacier-Till Contact, Iceland Photo by Tom Lowell 2 Striated Boulder, Hargraves Glacier, B.C. Photo by Tom Lowell Striated Boulder, Solheimajokull, Iceland. Photo by Tom Lowell Largest Erratic in Maine MAINE DEPARTMENT OF CONSERVATION PHOTO http://www.state.m e.us/doc/nrimc/pu bedinf/photogal/su rfical/surfphot.htm 3 DEPOSITIONAL LANDFORMS COMPOSED OF TILL: • Moraines = Ice-Marginal Positions Image from Judson L. Ahern http://dynamic.ou.edu/notes/glaciers/moraines.jpg Alpine Moraines Moraine = Landform on Margins of Glacier Lateral Moraine Medial Moraine End Moraine Medial Moraines 4 Photo by Tom Lowell Moraine System, Sierra Nevada, California Massive Lateral & End Moraines New Zealand Photo by Tom Lowell 5 End Moraines Terminal Moraine Recessional Moraines Athabaska Glacier, Alberta Moraine from “Continental” Glaciers: Iceland Photo by Tom Lowell http://www.state .me.us/doc/nrim 700c/pubedinf/facts m ht/bedrock/meg eol.htm Basin Ponds Moraine <60 m Mt. Katahdin, Maine 6 Frozen-Bed Margins (e.g. MN, WI, RI) Wet Bed Freezing Bed Frozen Bed Wet-Melting Wet-Freezing Frozen Frozen-Bed Margins Abrasion Plucking No Erosion Abrasion Plucking Stagnant Frozen-Bed Margins Su pra gla Basal De ci br al Debris is l Debris Flow Englacia Subglacial Till Debris Plucking Stagnant 7 Frozen-Bed Moraines End Moraine Ground “Moraine” Moraine Ridge Hummocky Topo Drumlins Kettle Moraine State Park, Wisconsin Till Plain Outwash 10 ft. contours Frozen-Bed Margin Drainage Ground Moraine Moraine Hummocky Ridge Moraine 8 Wet-Bed Moraines (OH, IN, IL, PA) Wet Bed Wet-Melting Wet-Bed Moraines Wet Bed Lodgement Frozen-Bed Margin Drainage Ground Moraine End Moraine = Thick Ground Moraine End Moraine Ground “Moraine” Lodgement Till 9 Outwash at Wet-Bed Moraines Wet Bed Outwash Conforms to Topography Outwash Wet-Bed Margin Drainage Ground Moraine End Moraine = Thick Ground Moraine End Moraine Ground Pitted Outwash “Moraine” Outwash Plain Moraine, Adams Co., Indiana, near Ohio border 5 ft. contours 10 What is the Age of Each Moraine? Assume Moraines are in Northern Hemisphere North South Apply Rules of “Morphostratigraphy” • What is the Age of Each Moraine? Last Next First ?? ? North South Till Stratigraphy in Moraines • Retreat with Still-Stand Sequence • What is the Age of Each Moraine? Last Next First North South 11 Till Stratigraphy in Moraines • Retreat with Readvance Sequence • What is the Age of Each Moraine? Last Next First 3 2 1 North South Compound (Palimpsest) Moraines • Stratigraphy = Better Age Indicator than “Morphostratigraphy” Last Next First 3 1 2 North South Minor Moraines • Ice-push Moraines (Bulldozer in Winter, vs. Conveyor Belt) • De Geer Moraines (Annual) • Washboard Moraines (Grounding Line Retreat) 12 Minor Moraines, Sedgewick, Maine MAINE DEPARTMENT OF CONSERVATION PHOTO http://www.state.m e.us/doc/nrimc/pu bedinf/photogal/su rfical/surfphot.htm Minor Moraines, Coastal Maine MAINE DEPARTMENT OF CONSERVATION PHOTO http://www.state.m e.us/doc/nrimc/pu bedinf/photogal/su rfical/surfphot.htm Not True Moraines, Despite Names • Ground Moraine • Pseudo-moraines (stacked thrust sheets of till or bedrock) • Rogen Moraine (compressive flow in enclosed basins) 13 Fluted Till Saskatchewan Glacier, Banff National Park • Tom Lowell Photo Drumlins, near Charlevoix, Michigan Photo by Lou Maher, Univ. of Wisconsin Drumlin near Madison, Wisconsin • Photo by Dave Mickelson 14 Kettle Moraine Drumlins Frozen-Bed Margin Drainage Ground Moraine Drumlins Hummocky Moraine Moraine Ridge Frozen-Bed Margin Drainage Wet Bed Freezing Bed Out-Burst Flooding Frozen Bed 15 Frozen-Bed Margin Drainage Wet Bed Freezing Bed Frozen Bed Frozen-Bed Margin Drainage Ground Moraine Eskers Drumlins ns Fa h as w ut O Tunnel Outwash Valleys Plain Cedar Creek Tunnel Valley, Adams Co., Indiana 16 Deposits Related to Glaciers • Outwash - Glaciofluvial • Glaciolacustrine •Glaciomarine • (Glacio) Aeolian • (Glacio) Colluvial Ice-Contact Stratified Drift (ICSD) • Variable Sorting • Variety of Bedforms & Other Sedimentary Structures • Collapse Features (e.g. Normal Faults) Landforms Associated with Meltwater (ICSD) • Eskers • Kames • Kame Terraces • Pitted Outwash •Outwash 17 Esker • Significance to Flow (Stagnant or Passive) • Subglacial, Englacial, Supraglacial or Ice-Walled • Segments, Bifurcations • X-Section, w/ Crs Gravel Core Possible Esker Positions Ice- Walled Supraglacial Englacial Subglacial Ice Cave Mendenhall Glacier, AK Photographer: John Bortniak, 1991 NOAA Corps http://www.photolib.noaa.gov/ lb_images/corps/corp1964.htm 18 Plugged Esker Tube, Angel Glacier, Jasper NP, Alberta Photo by Doug McVey Esker Evolution Esker Evolution: Post Ablation Maine Esker, ME GS photo Collapse Structures 19 Glacial "Water-Table", 3D Network, May Have Local Flow "Up Hill" (i.e. Up Subsurface Topography) “Up Slope” Eskers 0 Ice Surface Glacier” Water Table” Esker Flow Paleocurrent Indicators Esker, Kezar Ponds, Maine MAINE DEPARTMENT OF CONSERVATION PHOTO http://www.state.m e.us/doc/nrimc/pu bedinf/photogal/su rfical/surfphot.htm 20 Enfield Horseback, (= Esker) near Passadumkeag, Maine Kames: irregular to hummocky positive topographic features composed of ICSD Kame, Maine Geol. Survey 21 Moulin Kame Supraglacial Runoff Ice Ice Ice-Contact Fan Supraglacial Runoff Ice Moulin Kame: Garriety Hill 7 km NE of Dundee, Wisconsin Moulin Kames Photo by Lou Maher, Univ. of Wisconsin 22 1 km Most Ice-Contact Deltas are Gilbert Deltas Topset Ice Foreset Bottomset MAINE DEPARTMENT OF CONSERVATION PHOTO Topset Paleo-Base Level Foreset 23 Ice-Contact Delta, Maine MAINE DEPARTMENT OF CONSERVATION PHOTO Topset Paleo-Base Level Foreset Colluvium http://www.state.me.us/doc/nrimc/pub edinf/photogal/surfical/surfphot.htm Ice-Walled Lake Plain Ice Ice Ice-Walled Lake Plain Ice Ice 24 Ice-Walled Lake Plain Submarine Psuedo-Deltas, Maine Ice Ice Shelf Ice Sheet Berg SubglacialEsker Runoff Ice-Rafted Detritus Grounding Line 25 Ice-Marginal Streams Erosional Depositional Runoff Kame Terrace, Newcastle, Western PA Photo by Gary Fleeger, PA Geol. Survey Ice-marginal (Meltwater) Channels & Kame Terraces • Landform depends on Sediment Supply and Stream Power 26 Outwash • Outwash Head (Ice-marginal position) • Outwash Fan • Outwash Plain • Pitted Outwash - Kettles • Valley Train - Confined to Valley Kite Stream Outwash Kite Stream, Victoria Valley, Antacrtica Outwash of Skeidarasandur 27 Outflow to Skeidarasandur Outwash of Skeidarasandur Multiple Outwash (Depositional) Terraces O1 28 Multiple Outwash (Depositional) Terraces O2 O2 O1 Multiple Outwash (Depositional) Terraces O2 O2 O1 29.