10-5 Multi-Proxy Evidence for the M2 (?) Glaciation and Mid-Pliocene Warm Period at ODP Exp 151 Site 908

Session: Undergraduate and Graduate Geoscience Student Showcase (Posters)

Poster Booth No.: 62

Presenting Author:

Kristen Nehring

Authors:

Nehring, Kristen¹, DaPonte, Sydney², Davis, Reagen ³, Hammond, Ava⁴, McCollum, Joshua⁵, Oldham, Isaac⁶, Price, Malinee⁷, Rosa, Sophia⁸, Viskupic, Olivia⁹, St John, Kristen¹⁰

(1) Department of Geology & Environmental Science, James Madison University, Harrisonburg, VA, USA, (2) Department of Geology & Environmental Science, James Madison University, Harrisonburg, Virginia, USA, (3) Department of Geology & Environmental Science, James Madison University, Harrisonburg, Virginia, USA, (4) Department of Geology & Environmental Science, James Madison University, Harrisonburg, Virginia, USA, (5) Department of Geology & Environmental Science, James Madison University, Harrisonburg, Virginia, USA, (6) Department of Geology & Environmental Science, James Madison University, Harrisonburg, Virginia, USA, (7) Department of Geology & Environmental Science, James Madison University, Harrisonburg, VA, USA, (8) Department of Geology & Environmental Science, James Madison University, Harrisonburg, VA, USA, (9) Department of Geology & Environmental Science, James Madison University, Harrisonburg, VA, USA, (10) Department of Geology & Environmental Science, James Madison University, Harrisonburg, VA, USA,

Abstract:

The mid-Pliocene Warm Period (mPWP; 3.264–3.025 Ma) represents an interval in Earth’s history when global temperatures and atmospheric CO₂ levels were high (~350-450 ppm). At the start of this warm period was the short-lived M2 glaciation (M2; 3.312-3.264 Ma), a significant event marked by colder temperatures, lower sea level, ocean circulation changes, and expansive Northern Hemisphere ice sheets. This study investigates sediments recovered from ODP Site 908, situated in the southern Fram Strait. The Fram Strait is the primary gateway between the Arctic Ocean and the Atlantic Ocean, and an ideal site for reconstructing mid-Pliocene climatic conditions. The M2 is well documented further north in the Fram Strait (e.g., ODP Site 911) but is not as well documented in the southern Fram Strait (e.g., nearby ODP Site 909). This study uses a multi-proxy approach to investigate 1) whether changes in sediment transport mechanisms (IRD) can be identified across an expected stratigraphic interval spanning the M2-mPWP, and 2) whether bottom current speeds changed and if these changes coincide with the changing climates. These questions were addressed through grain size analysis (LDPSA, sieving), compositional census (binocular point counting), and XRF analyses of 37 samples between 113.45 and 121.88 mbsf. 

While uncertainties in the age model exist, results show a distinct stratigraphic interval from ~117 to 119 mbsf that may correlate with the M2. This interval is characterized by elevated amounts of mineral and rock fragments (IRD), small sortable silt mean sizes, low Ti/K, and reduced amounts of glauconite. These proxies suggest expansive ice sheets, slower bottom current speeds, and diminished terrigenous clays. This cold interval is situated between two warmer intervals, the latter of which may correlate with the mPWP. These intervals both show reduced amounts of IRD, larger sortable silt mean sizes, high Ti/K, and increased amounts of glauconite. These proxies indicate faster bottom currents, reduced ice volume, and an increase in terrigenous clays. Warmer intervals show increased variability of proxies in comparison to the cooler interval. Results align with previous studies documenting mid-Pliocene climates in the Arctic; however, it is uncertain if the cool interval is depicting the M2. Slight age model offsets indicate the possibility of Site 908 age model refinements and event clarity. 

Geological Society of America Abstracts with Programs. Vol. 58, No. 1, 2026

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