Devonian-Early Carboniferous climate change: glacial deposits and proxy records
Geological Society of America Annual Meeting

Philadelphia, Pennsylvania

October 22-25, 2006

Conveners: Peter Isaacson isaacson@uidaho.edu & Tom Algeo  Thomas.Algeo@uc.edu

Synopsis: The Devonian to Early Carboniferous interval represents the initial change between the global greenhouse climate of the early to mid-Paleozoic and the major continental glaciations of the late Paleozoic.  An episode of continental glaciation during the latest Devonian is now well documented from glacial deposits in South America, Africa, and eastern Laurentia as well as from sequence stratigraphic and geochemical proxy records elsewhere.  The causes, duration, and significance of this glaciation remain uncertain, however.  Among the factors that may have influenced global climate change during the Middle to Late Devonian are concurrent changes in terrestrial floral assemblages, weathering rates and patterns, emergence of the Acadian and Variscan orogens, volcanic and submarine hydrothermal activity, and atmospheric pCO2 and pO2.  Cause- and-effect relationships among these factors and their relative importance for Devonian-Early Carboniferous global events are areas of continuing research upon which this session is intended to focus.  A particular challenge is to determine the relative timing and causal linkages between penecontemporaneous events in the marine and terrestrial realms.  The significance of the end- Devonian glaciation for subsequent climate evolution also remains uncertain—was this an isolated event or the first step in a continuing process of global cooling that led to growth of large continental icesheets by the mid-Carboniferous?  What role did climate change in general and the end-Devonian glaciation in particular play in contemporaneous biotic extinctions and turnovers?  Our goal in proposing this session is to bring together researchers from a wide range of geologic subdisciplines who have worked on the Devonian or Early Carboniferous in order to promote interdisciplinary discussion and integration of diverse datasets relevant to these issues.  To this end, we would like to bring together researchers from the following geologic communities: glacial geologists, paleoclimate modelers, sedimentary geochemists, sequence stratigraphers, paleobotanists, and marine paleontologists.

Invitation: We would like to invite you to submit an abstract for this session.  If you know of other colleagues who might like to contribute, please inform us so that we can contact them.  Please note that GSA’s online abstract submission site will become operational around April 1st, and that the deadline for submitting abstracts is July 11th.

Publication: If this theme session generates sufficient interest, we would like to generate a publication (i.e., set of papers) from it. This would take the form of either a GSA Special Paper or a special issue of a major journal.  If you think that you might like to contribute a manuscript to this project, please let us know early so that we can gauge interest and open negotiations with potential publishers.

Field trip: A one day, informal (i.e., not GSA-sponsored) field trip is planned to visit diamictite intervals of the latest Devonian Spechty Kopf Formation of Pennsylvania’s Anthracite region. Cecil et al. (2002) recently have showed that a polymict diamictite with faceted, striated, and polished clasts is present in the lower Spechty Kopf Formation.  This diamictite interval is interpreted to be glacial in origin. The Spechty Kopf unit is coeval with the more extensive Gondwana Devonian glacial event.  We invite interested individuals to a one day field trip examining Appalachian field evidence for Late Devonian glaciation. Participants would meet in Wilkes Barre, PA on Friday evening, October 20, 2006, at a hotel to be announced.  An overview will be given that evening by Vik Skema of the PA Geological Survey and David Brezinski of the Maryland Geological Survey.  The field trip, on Saturday, October 21, will involve two to three exemplary outcrops.  We intend to be in Philadelphia in time for the evening’s icebreaker.  Participants will be responsible for their own transportation, lodging and meals.

RSVP: We would like to make an initial assessment of interest in the project outlined above.  Please respond and let us know if you might 1) submit an abstract or 2) join the fieldtrip at the Annual GSA Meeting in Philadelphia, or if you would be 3) interested in submitting a manuscript for a publication project after the meeting.

Paleoclimates: Is the Past the Key to the Future?

American Association of Petroleum Geologists

International Conference and Exhibition

Perth, Australia, 5-8 November 2006

Conveners: Brian West ( brian.p.west@exxonmobil.com) & Paul Markwick (pjm@getech.leeds.ac.uk)

Abstract Deadline: 18 January 2006

More information about this meeting can be found at: http://www.aapg.org/perth/index.cfm

Synopsis: Session 0-64/P-64: Paleoclimates: Is the Past the Key to the Future?
 

The Earth's climate has changed radically through geologic time and this has been recognized since the early 19th century. But, only in the last two decades have computer-based climate models become sophisticated enough to robustly represent these changes. Because depositional systems are intrinsically dictated by contemporary climate and oceanography, these models have now become a powerful tool in frontier exploration, especially for predicting the past distribution and character of source, reservoir and seal facies. These are the same models that are used for assessing the nature and impact of future climate change. Therefore, understanding the veracity of model results is crucial for both explorationists and policy makers alike. Indeed, with current predictions of future concentrations of atmospheric CO2 on the order of 2x pre-industrial values by 2100, the pre-Pleistocene record may be our only guide to the future response of the climate system to such changes. Consequently, an important role of paleoclimate studies is to quantitatively test model results for widely varying climate states using geologic data from both the public domain and, where possible, the wealth of high quality data diligently collected by the oil Industry over the past century.
  
The goal of this session is therefore to bring together climate modelers, paleoclimatologists and explorationists in order to understand the past history of climate, the strengths and weakness of both paleoclimate models and data, and what implications this has for applications in oil and gas exploration as well as climate change research. We especially wish to encourage submissions from researchers involved in 'ground-truthing' model results through quantitative and qualitative data-model comparison.

Raiding the Palaeozoic/Mesozoic sedimentary archive:investigating environmental change with multiple proxies (SSP 10)

European Geosciences Union
General Assembly 2006
Vienna, Austria, 2 - 7 April 2006

Convenors:  Ian Jarvis, Hugh Jenkyns, Isabel Montañez & Adrian Immenhauser

The symposium is being co-sponsored by IAS and EGU, and in association with the symposium we hope to produce an IAS Special Publication based on the papers presented at the meeting.  The general meeting (EGU 2006) home site is at http://meetings.copernicus.org/egu2006/
 
Abstract Deadline: 13 January 2006
 
Aim:  To bring together palaeontologists, sedimentologists, stratigraphers, organic and inorganic geochemists and palaeoceanographers to demonstrate how multiple palaeoenvironmental proxies can be applied to Palaeozoic and Mesozoic sedimentary successions to better understand and model major shifts and perturbations in the Earth System, including oceanic anoxic events, extinction events, and climate change.
 
Background:  Over the last two decades, the combination of carbon and oxygen stable isotope records with palaeontological and sedimentological proxies has proven to be a powerful tool in advancing our understanding of palaeoclimate and other palaeoenvironmental change through the Palaeozoic – Mesozoic.  Strontium isotopes have provided a new stratigraphic tool and have improved our knowledge of variations in the continental weathering flux.  Nonetheless, most records of Palaeozoic – Mesozoic environmental change remain largely qualitative.  However, considerable scope now exists for improved quantification and modelling by employing a multi-proxy approach that incorporates newly developed methods, such as:

 
Elemental chemistry:  productivity proxies using P, Ba, and Cd/Ca ratios; improved palaeotemperature, palaeoclimate and sea-level change records employing Sr, Mn, Mg/Ca and Sr/Ca ratios.
 
Novel isotope systems:  B, Ca, Ge, Li, Mg, Os and Si isotopes to assess variables including palaeoclimate, palaeo-pH, and hydrothermal versus continental weathering fluxes. Nd isotopes to trace ancient water masses.
 
Organic geochemical proxies:  Applications of the TEX86 palaeotemperature proxy.  Carbon and N isotope studies of biomarkers to devolve terrestrial and marine records of carbon cycle perturbations.  Biomarker distributions in deep ocean sediments as indicators of photic zone anoxia.
 
We do not have any funds to support speakers, but IAS are offering travel grants to post-graduate student members (http://www.iasnet.org/), so if you have any students working in this area please encourage them to apply.

Geosystems: Ancient Greenhouse Emissions and Hothouse Climates

AAAS Annual Meeting, Saint Louis, MO
February 16-20, 2006

Organizers: Isabel Montañez, (montanez@geology.ucdavis.edu) & Gerald Dickens (jerry@rice.edu)

Synopsis: At current projections, our society will add 3,000-5,000 gigatons of carbon to the atmosphere before exhausting fossil fuel resources. The prospect of greenhouse gas increases of geologic magnitude will likely have global consequences for the climate, ocean circulation, hydrography, and the health of the biosphere that are unparalleled in the Quaternary record. The deep-time (pre-Quaternary) rock record offers multiple time intervals of extreme warmth, some with minimal increases in atmospheric carbon dioxide and others clearly linked to massive greenhouse gas emissions. Studies document that these past intervals of warming were associated with major changes in climate patterns and biological diversity, both on land and in the ocean. Short-term (<100,000 years) examples of massive greenhouse gas emissions include onsets of oceanic anoxic events throughout the mid- to late-Cretaceous and the Paleocene-Eocene thermal maximum. Longer-term intervals of significant warming appear to have been superimposed on icehouse worlds of the late Paleozoic (320 to 280 million years ago) and late Cenozoic, including the Pliocene (~3 million years ago), the last period of sustained global warmth. Notably, the small changes in atmospheric carbon dioxide that characterized the Pliocene global warming drove significant changes in the climate system by destabilizing critical components of that system, thus indicating that future global warming could be substantially worse than currently estimated by numerical simulations. In this session, we examine three of these major periods of hothouse climates and their associated greenhouse gas levels from the deep-time geological perspective provided by atmospheric-ocean models and integrated geologic, chemical, and biologic proxy records.

Talk titles & speakers :

Resolving the environmental record at the onset of Oceanic Anoxic Events: Implications for biotic response
Tim Bralower, Pennsylvania State University

Integrated model-data reconstructions of Late Cretaceous tropical temperatures and atmospheric CO2
Karen Bice, Woods Hole Oceanographic Institution
Marine-terrestrial linkages during a Cretaceous Ocean Anoxic Event
Brad Sageman, Northwestern University

Extreme oceanic change at the Paleocene-Eocene boundary: Implications for past
and future carbon sequestration
James Zachos, University of California, Santa Cruz

Deep-sea biota: Consequences of massive greenhouse gas emissions
Ellen Thomas, Wesleyan University

Response of mid-latitude floras to rapid global warming at the Paleocene-Eocene boundary
Scott Wing, Smithsonian Museum of Natural History

The last great global warming: A modeling perspective into mid-Pliocene climate
Mark Chandler, Columbia University

Discussion (30 minutes) led by Gerald Dickens (Discussant) - address
and contact information as above