Quaternary Environments Non-Marine Biological Evidence Proxy Records Macrofossil Evidence Packrats Tree-line Microfossil Evidence Pollen fluctuation Insects.
Download ReportTranscript Quaternary Environments Non-Marine Biological Evidence Proxy Records Macrofossil Evidence Packrats Tree-line Microfossil Evidence Pollen fluctuation Insects.
Quaternary Environments Non-Marine Biological Evidence Proxy Records Macrofossil Evidence Packrats Tree-line Microfossil Evidence Pollen fluctuation Insects Macrofossil Evidence Quantitative analysis of Quaternary plant macrofossils began in 1957 (West 1957) Seeds, fruits (orchids to coconuts), cones, sporangia Leaves, needles, buds Wood Macrofossil Seeds Needle Cross Section Macrofossil Diagram Paleoscatology Scat Procedure Blend Screen Coprolites Analysis Can identify food sources and disease Cuticles Waxy coating that has distinct morphology Stomata: control gas exchange Trichomes (leaf hairs) Cork cells (provide leaf support) Silica cells (support, discourage foliavores) Phytoliths Production Disperal Silica is deposited in the secondary plant wall of some plants, particularly grasses and occasionally in wood. Phytoliths most abundant in grasslands and steppes. Large fragments move short distances (fragile) small fragments (silt sized) may be distributed by wind. Preservation Resistant to oxidation, but the silica can be dissolved by ground-water movement Phytolith Morphology Poaceae Zea luxuriens Phytolith Poaceae Paspalum lividum Phytolith Asteraceae Lipochaeta sp. Phytolith Phytoliths Identification Many plants don't produce phytoliths: only a partial indication of plants in area Non-related species produce the same types : dumbbells, saddles, bowls, boats, bottoms Some Taxonomic categories can be recognized: panicoid, festucoid, chloroid A few forms are diagnostic to species level: e.g., maize Phytolith Methods Oxidize sample (boil in H2O2) Wet sieve (phytoliths silt size) Flotation (tetrabromoethane, ZnBr2) phytoliths have specific gravity of 1.5-2.3, quartz 2.65 Wood Anatomy Can identify wood to the species or genus level Cell structure Pits Tracheids Pores Resin ducts Wood Anatomy Treeline Upper Treeline Temperature controlled Dating wood from tree above current treeline Arctic brown paleosols beneath recent Spodosols Lower Treeline Moisture controlled Packrat Middens Krummholz Prostrate stunted vegetation Protected by snow pack Can grow above present treeline Technically a different genetic species of a plant that has stunted growth, but broadly used for environmentally stunted trees Flagged leaders standing out from a Krummholz matt ©Tom Kloster 2001: http://www.splintercat.org/JeffParkRidge/ParkRidgeImages/ ©Tom Kloster 2001: http://www.splintercat.org/JeffParkRidge/ParkRidgeImages/ http://patti.tensegrity.net/album/moraine/display/trees.html Problems with Treeline Studies Incomplete fossil record (highest elevation trees may not have been found) Elevation of mountain summits restrict how high treeline could be recorded Present treeline is hard to determine Disturbances can affect tree line (fire, grazing, avalanches, wind abrasion, insects) Lag time in response to climate changes Advance faster than retreat Treeline may be affected by isostatic uplift Treeline Fluctuations, Sweden Dahl and Nesje 1996 Vegetation Zones with Elevation Vegetation Zones with Elevation Changes in Major Vegetation Zones for 22,000 years in Nevada Packrats (Neotoma) First used in Quaternary Paleoecology introduced by Phillip Wells (Wells and Jorgensen, 1964), a zoologist doing vegetation reconnaissance on the Nevada Test Site. Collect all vegetation around the midden Preserved by amberat (urine) Also bring in pollen Packrat Midden Locations Davis: http://www.geo.arizona.edu/palynology/geos462/28packrats.html Packrat Midden Packrat Midden Packrat Midden from University of Arizona (has Giant Sloth Bones) Macrofossils and Pollen from Packrat Middens Davis: http://www.geo.arizona.edu/palynology/geos462/28packrats.html Problems with Packrats Collected material may not represent a random representation of surrounding environment Different species have different preferences Discontinuous deposits Bioturbation Creosote Distribution From Packrat Middens Davis: http://www.geo.arizona.edu/palynology/geos462/28packrats.html Insect Studies Organisms used Coleoptera (Beetles) most common Diptera (Flies) Hymenoptera (Wasps and Ants) Found in sedimentary deposits such as lake beds or peat Based on exoskeleton morphology Little lag in assemblage changes Insects Study of late Quaternary beetle faunas began with Production Taphonomy poorly studied, but fossils are interpreted as local, however, many beetles can fly and their remains are present in streams. Preservation More species of beetles than of all other animals. Dispersal J.V. Matthews (1975) North American G.R. Coope's (1977) study of British deposits S.A. Elias (1985) western U.S. Beetle carapaces are the most resistant of all insect fossils. Their elytrae (chitinous wing covers) are particularly abundant, heads and legs also common. Identification Beetles are probably the best studied insect group (taxonomically), and their preserved remains useful in identification Beetle Morphology Reconstructed Paleotemperature Based on Insect Remains, UK Mutual Climate Range Chironomid Percentage Diagram