Raised Beaches Podcast: Episode 4

Raised Beaches Podcast: Episode 4

The deep dive of episode 4 is on Milankovitch Cycles.

Listen here: https://raisedbeaches.buzzsprout.com/

Watch here: https://www.youtube.com/@evangowan

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Episode 4 – Intro

I discuss what I have been doing in November and December 2024, as well as an overview of all of 2024.

• Current work on ice sheet reconstructions.
• Trip to Okinawa and a discussion on the sea level indicators there, based on beachrock.
• Some discussion of the Aso Caldera in Kyushu.
• The anomalously hot water around Japan, and how it is affecting the fisheries.
• The ammonite fossil exhibit at Kumamoto University.
• Overview of my activities in 2024.

References:

• Evelpidou et al (2019) – Evolution of relative sea level in Okinawa (Japan) during Holocene: https://doi.org/10.4461/GFDQ.2019.42.1
• News report by Nippon Television on the migration of the Ise Ebi due to warming ocean water temperatures: https://www.youtube.com/watch?v=Bvn5g0uKHSU

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Episode 4 Deep Dive – Milankovitch Cycles

I introduce Milankovitch Orbital Theory and Milankovitch Cycles, and why orbital variability is the main control on paleoclimate changes. I also give examples of well known proxy records that demonstrate Milankovitch Cycles.

References:

• Milutin Milanković on Wikipedia: https://en.wikipedia.org/wiki/Milutin_Milankovi%C4%87
• Milankovitch Cycles on NASA: https://science.nasa.gov/science-research/earth-science/milankovitch-orbital-cycles-and-their-role-in-earths-climate/
• Insolation calculator: https://vo.imcce.fr/insola/earth/online/earth/online/index.php
• Laskar et al (2004) – A long term numerical solution for the insolation quantities of the Earth: https://doi.org/10.1051/0004-6361:20041335
• The LR04 Stack: https://lorraine-lisiecki.com/stack.html
• Lisiecki and Raymo (2005) – A Pliocene-Pleistocene stack of 57 globally distributed benthic δ18O records: https://doi.org/10.1029/2004PA001071
• Wang et al (2008) – Millennial- and orbital-scale changes in the East Asian monsoon over the past 224,000 years: https://doi.org/10.1038/nature06692

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Episode 4 – More on Milankovitch Cycles

I discuss about James Croll’s hypothesis on orbital changes being responsible for climate changes, which predates Milankovitch’s theory, Charles Darwin’s remarks on it, as well as why it was not accepted. I also discuss Milankovitch Cycles on Mars.

References:

• James Croll on Wikipedia: https://en.wikipedia.org/wiki/James_Croll
• Croll (1864): On the Physical Cause of the Change of Climate During Geological Epochs: https://www.google.ca/books/edition/Philosophical_Magazine/2DBDAQAAMAAJ?hl=en&gbpv=0
• Arrhenius (1896) – On the influence of carbonic acid in the air upon the temperature of the ground: https://doi.org/10.1080/14786449608620846
• Touma and Wisdom (1993) – The Chaotic obliquity of Mars: https://doi.org/10.1126/science.259.5099.1294
• Head et al (2003) – Recent ice ages on Mars: https://doi.org/10.1038/nature02114
• Mars Glacier in Hellas Planitia, NASA/JPL-Caltech/UArizona: https://hirise.lpl.arizona.edu/PSP_002320_1415

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Episode 4 – Papers

I discuss a paper that I am coauthor on, led by Karla Rubio-Sandoval, which is an investigation of four raised beach/shoreline deposits in Camarones, Argentina. This research was part of the WARMCOASTS project, which I was part of.

References:

• Rubio-Sandoval et al (2024) – Quaternary and Pliocene sea-level changes at Camarones, central Patagonia, Argentina: https://doi.org/10.1016/j.quascirev.2024.108999
• Rovere et al (2020) – Higher than present global mean sea level recorded by an Early Pliocene intertidal unit in Patagonia (Argentina): https://doi.org/10.1038/s43247-020-00067-6
• Gowan et al (2024) – Last interglacial (MIS 5e) sea-level proxies in southeastern South America: https://doi.org/10.5194/essd-13-171-2021

Thanks to Alessio Rovere for some of the pictures used here, and of course for being a great mentor on investigating raised coastal deposits!

WARMCOASTS – Sea level and extreme waves in the Last Interglacial: This project received funding from the European Research Council (ERC) under the European Union’s Horizon 2020 research and innovation program (grant agreement no. 802414)

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Thank you to:

Raised Beaches Podcast logo by Aurooj: https://www.instagram.com/artbytinyleaf/
Sean for the Raised Beaches Podcast theme song
That Blasted Salami, who helped me get started: https://www.youtube.com/channel/UC5GTc4yWm-yiBFTuV3MsGaQ

Follow Dr. Evan J. Gowan on social media:

Mastodon: @DrEvanGowan@fediscience.org

Bluesky: @evangowan.bsky.social