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• 1. [Article] Investigating the Holocene History of Eliot Glacier, Mount Hood, Oregon

  This research documents the Holocene glacial history of Mount Hood, Cascade Mountains, Oregon by analyzing a set of three lateral moraines abutting Eliot Glacier, the largest glacier on the mountain. This ...

  Citation × Citation Citation Abstract Copy Title: Investigating the Holocene History of Eliot Glacier, Mount Hood, Oregon Author: Jones, Nadia Sittara Year: 2012 This research documents the Holocene glacial history of Mount Hood, Cascade Mountains, Oregon by analyzing a set of three lateral moraines abutting Eliot Glacier, the largest glacier on the mountain. This study seeks to: 1) establish the relative ages of these lateral moraines and 2) determine if these features represent distinct glacial advances. The hypothesis is that the lateral moraines for Eliot Glacier represent three distinct periods of glacial advance based on their position relative to the current glacier and other diagnostic indicators. Soil profiles of three positions (shoulder, backslope, and footslope) on the distal side of each lateral moraine were described in the field and samples were taken from each horizon for laboratory analyses of pH and particle size. The results of the soil analysis show that the soils developing on the moraine closest to the current glacier are poorly developed and significantly younger than the other two features. The closest moraine likely dates to the Little Ice Age (600-150 YBP) and has soils with an A/C profile and a classification of Andic Cryopsamment. The soils on the middle and furthest moraines from the glacier are similar in the profile sequence (Andic Haplocryepts). Silt bulges were noted in the mid-slope pits. The furthest moraine has deeper horizons and more color development than the middle moraine. Ash layers were found in the backslope soil profile (36-51cm deep) on the middle moraine. Additional lab testing confirms the ash layers originated from Mount Hood, but no date can be assigned. The eruptive history of Mount Hood points to the Timberline eruptive period (1,500 YBP) as a likely candidate for one of the ash deposits. This evidence suggests the middle moraine was actively forming during this period and is intermediate in age between the furthest moraine and the Little Ice Age Moraine; hence, this sequence of moraines indicates three distinct periods of glacial advance in the Neoglacial. Title: Investigating the Holocene History of Eliot Glacier, Mount Hood, Oregon Author: Jones, Nadia Sittara Year: 2012 This research documents the Holocene glacial history of Mount Hood, Cascade Mountains, Oregon by analyzing a set of three lateral moraines abutting Eliot Glacier, the largest glacier on the mountain. This study seeks to: 1) establish the relative ages of these lateral moraines and 2) determine if these features represent distinct glacial advances. The hypothesis is that the lateral moraines for Eliot Glacier represent three distinct periods of glacial advance based on their position relative to the current glacier and other diagnostic indicators. Soil profiles of three positions (shoulder, backslope, and footslope) on the distal side of each lateral moraine were described in the field and samples were taken from each horizon for laboratory analyses of pH and particle size. The results of the soil analysis show that the soils developing on the moraine closest to the current glacier are poorly developed and significantly younger than the other two features. The closest moraine likely dates to the Little Ice Age (600-150 YBP) and has soils with an A/C profile and a classification of Andic Cryopsamment. The soils on the middle and furthest moraines from the glacier are similar in the profile sequence (Andic Haplocryepts). Silt bulges were noted in the mid-slope pits. The furthest moraine has deeper horizons and more color development than the middle moraine. Ash layers were found in the backslope soil profile (36-51cm deep) on the middle moraine. Additional lab testing confirms the ash layers originated from Mount Hood, but no date can be assigned. The eruptive history of Mount Hood points to the Timberline eruptive period (1,500 YBP) as a likely candidate for one of the ash deposits. This evidence suggests the middle moraine was actively forming during this period and is intermediate in age between the furthest moraine and the Little Ice Age Moraine; hence, this sequence of moraines indicates three distinct periods of glacial advance in the Neoglacial. Close

• 2. [Article] The Neoglacial History of Mt. Thielsen, Southern Oregon Cascades

  Little Ice Age (LIA) deposits are recognized on Mt. Tbielsen, southern Oregon Cascades (43° 9' N, 122° 3' W), based on particle morphology and relative position. The initial advance, Lathrop 1, created ...

  Citation × Citation Citation Abstract Copy Title: The Neoglacial History of Mt. Thielsen, Southern Oregon Cascades Author: Lafrenz, Martin Dietrich Year: 2001 Little Ice Age (LIA) deposits are recognized on Mt. Tbielsen, southern Oregon Cascades (43° 9' N, 122° 3' W), based on particle morphology and relative position. The initial advance, Lathrop 1, created a sharp-crested moraine and a protalus rampart within 200 m of the headwall. The retreat of the glacier and recent ice movement, Lathrop 2, is recognized by the deformation of the moraine and a mantle of "protalus till" creating a polygenetic "push-deformation'' moraine. Both the moraine and the protalus rampart have sparse vegetation, no lichens, and a lightly weathered Cox/C soil. This sequence is correlative with LIA Phase 1 and Phase 2 on Mt. Jefferson, central Oregon Cascades, and is broadly correlated with LIA deposits throughout the Cascades, Sierra Nevada, and Rocky Mountains. There is no evidence for pre-LIA deposits at Mt. Thielsen. The ELA on Lathrop Glacier (2450 m) is lower than ELAs on nearby glaciers. The glacier probably exists because of its preferential topographic position and extensive debris cover; thus, if annual snowfall decreases the glacier will persist longer than a similar sized bare ice glacier. Conversely, a growing protalus rampart may indicate an increase in annual snowfall but not necessarily a decrease in annual temperatures. The lack of older Neoglacial deposits on Mt. Thielsen may be a result of insufficient snowfall to maintain or advance the Lathrop Glacier. As such, the LIA may represent a period when climatic conditions were more severe than at any other time in the Neoglacial. Boulder size, shape, and orientation proved useful for classifying geomorphic features and assessing the relative ages of slopes. However, soils are the best method for correlating deposits in the cirque with other locations. Soils beyond the moraine are developed in Mazama ash and have moderately developed Bw horizons, depth to weathering over 70 cm, and Harden's PDI for B horizons of 2.10-3.64. Soils are Typic Vitricryands. Title: The Neoglacial History of Mt. Thielsen, Southern Oregon Cascades Author: Lafrenz, Martin Dietrich Year: 2001 Little Ice Age (LIA) deposits are recognized on Mt. Tbielsen, southern Oregon Cascades (43° 9' N, 122° 3' W), based on particle morphology and relative position. The initial advance, Lathrop 1, created a sharp-crested moraine and a protalus rampart within 200 m of the headwall. The retreat of the glacier and recent ice movement, Lathrop 2, is recognized by the deformation of the moraine and a mantle of "protalus till" creating a polygenetic "push-deformation'' moraine. Both the moraine and the protalus rampart have sparse vegetation, no lichens, and a lightly weathered Cox/C soil. This sequence is correlative with LIA Phase 1 and Phase 2 on Mt. Jefferson, central Oregon Cascades, and is broadly correlated with LIA deposits throughout the Cascades, Sierra Nevada, and Rocky Mountains. There is no evidence for pre-LIA deposits at Mt. Thielsen. The ELA on Lathrop Glacier (2450 m) is lower than ELAs on nearby glaciers. The glacier probably exists because of its preferential topographic position and extensive debris cover; thus, if annual snowfall decreases the glacier will persist longer than a similar sized bare ice glacier. Conversely, a growing protalus rampart may indicate an increase in annual snowfall but not necessarily a decrease in annual temperatures. The lack of older Neoglacial deposits on Mt. Thielsen may be a result of insufficient snowfall to maintain or advance the Lathrop Glacier. As such, the LIA may represent a period when climatic conditions were more severe than at any other time in the Neoglacial. Boulder size, shape, and orientation proved useful for classifying geomorphic features and assessing the relative ages of slopes. However, soils are the best method for correlating deposits in the cirque with other locations. Soils beyond the moraine are developed in Mazama ash and have moderately developed Bw horizons, depth to weathering over 70 cm, and Harden's PDI for B horizons of 2.10-3.64. Soils are Typic Vitricryands. Close