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 Bed Freezing d Frozen Be
Wet-Melting Wet-Freezing Frozen
Frozen-Bed Margins
Abrasion
Plucking No Erosion
Abrasion Plucking Stagnant
Frozen-Bed Margins
Su pra gla De cial bri s Flow bris Basal al De Till glaci Debris En Subglacial Plucking Stagnant Debris
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
Moraine Hummocky Ridge Moraine
Frozen-Bed Margin Drainage
t Bed We Out-Burst Bed Freezing Flooding d Frozen Be
15 Frozen-Bed Margin Drainage
Wet Bed Bed Freezing d Frozen Be
Frozen-Bed Margin Drainage
Ground Moraine Eskers
s Drumlins n Fa h as tw u O Outwash Tunnel Plain Valleys
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