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Paleoclimatic and paleoecological implications of a Paleocene-Eocene fossil leaf assemblage, Chickaloon Formation, Alaska

David Sunderlin, Garrison Loope, Nancy E. Parker and Christopher J. Williams
Paleoclimatic and paleoecological implications of a Paleocene-Eocene fossil leaf assemblage, Chickaloon Formation, Alaska
Palaios (June 2011) 26 (6): 335-345

Abstract

New collections of a leaf compression-impression paleoflora preserved in fluvio-lacustrine sediments of the upper Chickaloon Formation, south-central Alaska, United States, provide leaf physiognomic climate estimates for the early Eocene in southern Alaska and rare data on plant-insect interactions from a subarctic setting. Thirty-nine broadleaf angiosperm morphotypes occur in a parautochthonous assemblage along with Metasequoia shoots and trunks, compressions of a diverse suite of seeds, monocotyledonous aquatic plants, freshwater gastropods, and inclusion-bearing dispersed amber. Leaf-character derived mean annual temperature estimates (11-14.6 degrees C) are significantly warmer than Alaska at present and indicate warm temperate conditions at the time of deposition. Leaf-derived mean annual precipitation estimates of approximately 110-160 cm/annum are comparable to those from similar-age paleofloras in Arctic Canada and indicate wetter conditions than nearly coeval paleofloras further south in the North American mid-latitudes. Leaf herbivory is rare in the Chickaloon assemblage ( approximately 9% of leaf fragments) as compared to other, lower latitude Eocene assemblages, but exhibits four of the main leaf-damage guilds (hole feeding, margin feeding, surface feeding, and skeletonization). These data provide a rare glimpse at a high-latitude terrestrial forested ecosystem during a global hothouse climate phase and thus have implications in understanding how biogeographic patterning and ecological systems respond to non-analog, warm high-latitude environmental conditions.


ISSN: 0883-1351
Serial Title: Palaios
Serial Volume: 26
Serial Issue: 6
Title: Paleoclimatic and paleoecological implications of a Paleocene-Eocene fossil leaf assemblage, Chickaloon Formation, Alaska
Affiliation: Lafayette College, Department of Geology and Environmental Geosciences, Easton, PA, United States
Pages: 335-345
Published: 201106
Text Language: English
Publisher: Society for Sedimentary Geology, Tulsa, OK, United States
References: 80
Accession Number: 2011-061489
Categories: Stratigraphy
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. strat. col., sect., 5 tables, geol. sketch map
N61°43'60" - N61°43'60", W148°56'60" - W148°56'60"
Secondary Affiliation: Oberlin College, USA, United StatesFranklin and Marshall College, USA, United States
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by SEPM (Society for Sedimentary Geology), Tulsa, OK, United States
Update Code: 201134
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