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Theme 10

Climate Evolution: Processes and Records

Gary Hemming, LDEO-Columbia,
Claude Hillaire-Marcel,

Co-hosted sessions

SESSIONS

10a. Proxy development for paleoclimate and paleocean chemistry

(co-hosted by Themes 10 and 13)

Co-convenors:
Ann Russell (University of California at Davis) - adrussellucdavis.edu
Pamela Martin (Indiana University-Purdue) - pamelaamartingmail.com
Bärbel Hönisch (Lamont-Doherty Earth Observatory) - hoenischldeo.columbia.edu

Development of geochemical proxies for reconstructing past climatic and ocean chemical conditions is a key component of paleoclimate and paleoceanographic research and essential for gleaning insight into the Earth’s future from its history. Archives of paleoenvironmental information include both biogenic and authigenic precipitates and isolating an environmental signal can be convoluted by post-depositional overgrowths. Covariation of environmental parameters can also make it difficult to calibrate the response of a proxy to a single environmental parameter. In deep time, additional complications can arise when the possible controls over proxy relationships are less constrained and different‐from‐modern seawater chemistry may change proxy relationships from the conditions under which the proxy was calibrated.

This session seeks to share progress on identifying the primary geochemical mechanisms and environmental controls over marine proxies, as well as approaches and tools for addressing post- depositional alteration. We welcome contributions focused on the geochemistry of proxies from carbonates, diatoms, organic material, as well as bulk sediments and authigenic precipitates. We encourage analytic method development and specifically contributions that go beyond empirical correlations between ocean parameters and proxy signals, which may improve the quality of proxy applications by delving into the mechanistic basis for the relationship.

Keynote speaker:
Jess Adkins (CalTech), jessgps.caltech.edu
Invited speakers:
Hagit Affek (Yale University), hagit.affekyale.edu
Alexander Gagnon (Lawrence Berkeley National Lab), acgagnonlbl.gov
Stephen Romaniello (Arizona State University), sromanieasu.edu

10b. Seawater chemistry changes through time

(co-hosted by Themes 10 and 13)

Co-convenors:
Troy Rasbury (SUNY-Stony Brook) - erasburynotes.cc.sunysb.edu
Lee Kump (Penn State University) - lkumppsu.edu)

Marine records are by far the highest resolution records of changes in the Earth system, including its climate history. We envision contributions on modern observations on the controls on seawater isotope and elemental values and from the archives from the geologic record. We are also interested in contributions that bear on the major element, trace element, radiogenic and non-radiogenic isotope compositions of fluids (or the altered products) that reflect the sources and sinks to the oceans, including rivers, subterranean groundwater discharge, interaction of hydrothermal solutions through ocean crust and overlying sediments (e.g., low temperature off-flank flux, reverse weathering, etc), and element and isotope abundances and residence times. Finally, we need to consider controls on Earth climate through models predicting changes in seawater chemistry.

Keynote speaker:
Fred T. Mackenzie (University of Hawaii), fredmsoest.hawaii.edu

10c. Past and future changes in ocean circulation

Co-convenors:
Eric Galbraith (GEOTOP-McGill University) - eric.galbraithmcgill.ca
Laura Robinson (University of Bristol) - laura.robinsonbristol.ac.uk

Despite decades of research, the large-scale drivers of deep-ocean circulation - and its susceptibility to change - remain poorly understood. Ocean mixing, especially vertical mixing, is of critical importance to this circulation, but is difficult to observe in the modern ocean. Paleoceanographic records offer great potential in constraining past changes in ocean circulation, which can help reveal natural variability of ocean mixing, while ocean models can provide insight into mechanisms, constrained by present-day observations. Together, these approaches help to predict the biogeochemical impacts of future changes in ocean circulation. This session aims to bring together geochemical observations and theory that can shed light on ocean mixing and its impacts on ocean circulation, and gas and nutrient cycling in the past, present and future. We invite contributions that can constrain or quantify deep ocean circulation on any timescale, and particularly encourage contributions that bear on vertical mixing in the ocean. We also welcome theoretical and modeling contributions that address the role of ocean circulation on biogeochemistry, or that help to interpret geochemical observations.

Keynote speaker:
Daniel Sigman (Princeton University), sigmanprinceton.edu

10d. The Cryosphere: Tracers, records and processes

Co-convenors :
Joerg Schaefer (Lamont Doherty Earth Observatory) - schaeferldeo.columbia.edu
Anne de Vernal (GEOTOP-UQAM) - devernal.anneuqam.ca
Martin Roy (GEOTOP-UQAM) - roy.martinuqam.ca
Alberto Reyes (University of Wisconsin-Madison) - avreyes2wisc.edu
Anders Carlson (Oregon State University) - acarlsongeology.wisc.edu
Camille Li (Bjerknes Centre for Climate Research, Norway) - camilleuib.no

The cryosphere is a major, highly vulnerable component of the Earth’s climate system, playing an important role in surface energy balance, freshwater budget, and sea-level fluctuations, while directly influencing ocean circulation and the biosphere. Past, present and future dynamics of ice sheets, mountain glaciers and sea ice are of highest relevance for earth scientists and our society alike. In spite of recent progress in strategies to document past and present changes of the cryosphere and advances in modeling efforts, a more quantitative, regional to global understanding of ice-climate processes is urgently needed.

This session invites contributions on all aspects of ice in the climate system: Geochemical data and modern observations documenting the evolution of the cryosphere, including ice sheets and mountain glaciers, ice-related impacts on ocean circulation, tracer studies of ice and meltwater discharge and records of sea ice variations, as well as model-based studies towards a clearer understanding of the proxy record in a dynamical framework.

Keynote speakers:
Sidney Hemming (Lamont-Doherty Earth Observatory), sidneyldeo.columbia.edu
Eric Steig (University of Washington) - steigess.washington.edu
Invited speakers:
Summer Rupper (Brigham Young University, U.S.A.), summer_rupperbyu.edu
Marcus Gutjahr (University of Southampton, UK), M.Gutjahrsoton.ac.uk
Aaron Putnam (University of Maine, U.S.A.), Aaron.Putnamumit.maine.edu
Ulysses Ninnemann (University of Bergen), ulysses.ninnemanngeo.uib.no
Simon T. Belt (Plymouth University, UK), sbeltplymouth.ac.uk
Claude Hillaire-Marcel (GEOTOP & UQAM), hillaire-marcel.claudeuqam.ca

10e. Geochemical approaches to reconstructing ice sheet history: modern processes and paleo-perspectives

Co-conveners:
Alberto Reyes (University of Wisconsin-Madison) - avreyes2wisc.edu
Anders Carlson (Oregon State University) - acarlsongeology.wisc.edu

SESSION MERGED with 10d

10f. Interpreting terrestrial geochemical proxy records of climate change

Co-convenors:
Paul Tomascak (SUNY-Oswego) - paul.tomascakoswego.edu
Sidney Hemming, (Lamont-Doherty Earth Observatory) - sidneyldeo.columbia.edu

The continental proxy record of climate change provides critical information for comparison with marine records. Deciphering the geochemical climate proxies stored in terrestrial archives poses unique challenges for paleoclimatologists. The geology and geochronology evidence is often cryptic and complicated, but if decoded these archives may offer unprecedented insight into coarse- and fine-scale climate variation. We seek abstracts presenting innovative approaches to the study of terrestrial climate records, including empirical studies of proxies based on field or laboratory investigations, records of terrestrial climate change on all time scales, geochronology developments for terrestrial time scales, and numerical simulations of climate change and associated proxy responses.

Keynote speaker:
Wallace S. Broecker (Lamont-Doherty Earth Observatory) – broeckerldeo.columbia.edu

10g. Paleotemperature proxies: processes and comparisons

Co-convenors:
Peter Douglas (Yale University) - peter.douglasyale.edu
Yige Zhang (Yale University) - yige.zhangyale.edu

Recently there has been a major expansion in the number of geochemical temperature proxies applied to paleoclimate studies, with techniques employing trace element ratios, the distribution of organic molecules, clumped isotopes and non-traditional stable isotopes, as well as new approaches to oxygen isotope paleothermometry. Nevertheless, there remains many fundamental questions regarding the underlying mechanisms controlling the temperature dependence of these chemical systems, the seasonality and environment of their preserved temperature signal and the extent to which other environmental variables bias recorded temperatures. This session will focus on critical analyses of temperature proxy data that seek to improve our understanding of these techniques and their application to understanding past changes in the Earth's climate. We especially encourage studies that analyze modern materials to test and refine paleotemperature proxy techniques, and multi-proxy paleoclimate studies that seek to understand the relationship between different proxies.

Keynote speaker:
Richard Pancost (University of Bristol) - r.d.pancostbristol.ac.uk
Invited speakers:
Ann Pearson (Harvard University), apearsoneps.harvard.edu
Michael Hren (The University of Tennessee at Knoxville), mrhenutk.edu
Zhengrong Wang (Yale University), zhengrong.wangyale.edu

10h. Deciphering unstable climate intervals: from the Cretaceous to the Pliocene

(co-hosted by Themes 10 and 13)

Co-convenors:
Peter Bijl (University of Utrecht) - P.K.Bijluu.nl
Steven Bohaty (University of Southampton) - S.Bohatysoton.ac.uk
Howie Scher (University of South Carolina) - hschergeol.sc.edu
Marcus Badger (University of Bristol) - marcus.badgerbristol.ac.uk
Miguel Martínez-Botí (University of Southampton) - M.A.Martinez-Botinoc.soton.ac.uk

Global scale proxies for deep-sea temperature, ice volume, and carbon dioxide have outlined the mean state of the pre-Pleistocene climate system. Departures from this mean state provide opportunities to evaluate the rapid response characteristics of the climate system. This session highlights recent advances in understanding anomalous departures from the global mean climate state on Pliocene to Cretaceous time scales. The warmth of the Pliocene prevailed with only slightly higher CO₂ levels than at present, and earth system boundary conditions (i.e., plate arrangements and biota) that were broadly similar today, providing an opportunity to evaluate how the earth system behaves in a warmer world. In the early Cenozoic, short-lived climatic departures from the long-term average reveal both unstable warm and cool climate episodes, that appear linked to ice volume, changes in ocean chemistry, and continental weathering. With this session we aim to bring together contributions from the climate record and modeling communities to address questions regarding how the earth system maintains its mean climate state as well as the magnitude, timing, duration, and frequency of unstable departures from the mean state.

Keynote speakers:
Tina van De Flierdt (Imperial College, London), tina.vandeflierdtimperial.ac.uk
Gerald H. Haug/Geological Institute, ETH Zürich, gerald.haugerdw.ethz.ch
Invited speakers:
Peter Douglas (Yale University), peter.douglasyale.edu
Alan Haywood (University of Leeds), A.M.Haywoodleeds.ac.uk

10i. Deciphering the Pliocene Warmth: records, causes and consequences

Co-convenors:
Marcus Badger (University of Bristol) - marcus.badgerbristol.ac.uk
Miguel Martínez-Botí (University of Southampton) - M.A.Martinez-Botinoc.soton.ac.uk

SESSION MERGED with 10h

10j. Ice-ocean-atmosphere interactions in the climate system

Co-convenors:
Sidney Hemming (Lamont Doherty Earth Observatory) - sidneyldeo.columbia.edu
Camille Li (Bjerknes Centre for Climate Research, Norway) - camilleuib.no

SESSION MERGED with 10d

Co-hosted sessions:

Please note that for abstract submission purposes, the following sessions and their respective descriptions appear in their primary Theme assignments (numbers in red or before the title).

7d.- Records of climate change from terrestrial archives: palaeosols and loess.

Co-convenors: Mohammed Rafi G. Sayyed/India and Martine Gerard/Paris
(co-hosted by Themes 7, 10 and 11).

7e.-The global weathering thermostat

Co-convenors: Heather Buss, Rich Pancost and Andy Ridgwell/University of Bristol
(co-hosted by Themes 7 and 10)

11a.- Biogeochemical cycling of aerosols and their effects in the evolving Earth’s climate

Co-convenors: Nicholas Meskhidze/NC State and Ina Tegen/Institute for Tropospheric Research, Leipzig
(co-hosted by Themes 11 and 10)

17f.- Frontiers in U-Series as tracers and chronometers of environmental processes and paleoclimatic archives

Co-convenors: Pierre Deschamps/CEREGE, Francois Chabaux/LHyGeS, Strasbourg, Andrea Dutton/University of Florida and Bassam Ghaleb, GEOTOP-UQAM
(co-hosted by Themes 17, 7 and 10)

17g.- Traditional and novel isotopes as tracers of weathering processes

Co-convenors: Jérôme Gaillardet/IPG-Paris, Sophie Opfergelt/Oxford, Thomas Bullen/USGS and Friendhelm von Blanckenburg/Postdam
(co-hosted by Themes 17, 7 and 10)

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