Upper Mantle Dynamics and
Quaternary Climate in Cratonic Areas

International Lithosphere Program (ILP) Regional Co-ordination Committee CC 1/5

A Joint DynaQlim / GGOS Workshop

The Global Geodetic Observing System (GGOS) of the International Association of Geodesy (IAG) and the International Lithosphere Program (ILP) Regional Co- ordination Committee DynaQlim invites scientists and experts to participate in the Joint DynaQlim/GGOS workshop "Understanding Glacial Isostatic Adjustment" to be held in Espoo, Finland June 23-26, 2009.

Background

GGOS is the Global Geodetic Observing System of the International Association of Geodesy (IAG). It provides observations of the three fundamental geodetic observables and their variations, that is, the Earth's shape, the Earth's gravity field and the Earth's rotational motion.  GGOS integrates different geodetic techniques, different models, different approaches in order to ensure a long-term, precise monitoring of the geodetic observables in agreement with the Integrated Global Observing Strategy (IGOS). GGOS provides the observational basis to maintain a stable, accurate and global reference frame and in this function is crucial for all Earth observation and many practical applications. (GGOS web page)

The ILP Regional Coordination Committee DynaQlim (Upper Mantle Dynamics and Quaternary Climate in Cratonic Areas) was established in 2007 for studying the relationship between Glacial Isostatic Adjustment (GIA), upper mantle structure, dynamics and Quaternary climate. It integrates existing data and models from a variety of disciplines that consider processes over a range of spatial and temporal scales relating to the Quaternary evolution of cratonic regions. A key aim will be to facilitate the development of various models in order to generate more accurate predictions of Earth and ice sheet evolution during the Quaternary, and thus to understand the past and contemporaneous evolution of topography in previously glaciated terrains. (DynaQlim web page)

The Local Organisers are the National Lithosphere Committee and the DynaQlim project, Finnish Geodetic Institute, and Geologial Survey of Finland.

Introduction

The phenomenon of glacial isostatic adjustment (GIA) with its unique temporal signatures is one of the great opportunities in geosciences for obtaining information about Earth processes. GIA contains information about recent climate forcing, being dependent on the geologically recent on- and off-loading of ice sheets; it presents a unique opportunity to study the dynamics and rheology of the lithosphere and asthenosphere with increasingly detailed models; and it is of fundamental importance in geodesy since the global reference frames, Earth rotation and polar motion are influenced by it. DynaQlim (Upper Mantle Dynamics and Quaternary Climate in Cratonic Areas), a project of the International Lithosphere Program, aims to understand the relationship between upper mantle dynamics, mantle and lithosphere composition, and their physical properties in order study GIA, climate variations, and Weichselian glaciations during the Quaternary.

Geodesy provides accurate measurements of contemporary deformation and gravity change. Space geodetic techniques, such as GPS, allow the construction of 3-D motions from relatively short (less than 10 years) time series. And variations in gravity can be determined from both ground-based and space-based instruments. These position and gravity measurements can be used to both constrain models of glacial isostatic adjustment and to verify and validate the models. The global geodetic observing system (GGOS), a component of the International Association of Geodesy, provides the geodetic infrastructure necessary for monitoring the Earth system, including the site position and gravity measurements that are important to determining models of glacial isostatic adjustment.


Workshop objectives

The objective of the workshop is to

• review the current state of the science in modeling glacial isostatic adjustment, 
• review the use of geodetic measurements to both constrain and to test GIA models,
• identify obstacles to improving GIA models, and
• identify the improvements to the global geodetic observing system that are required to advance our understanding of glacial isostatic adjustment.

Expected Outcome

The major outcome of the workshop will be a report summarizing the current state of the science, a description of future research directions, and a description of the future observations that are needed to improve our understanding of glacial isostatic adjustment. The report will include sections on:

• models of glacial isostatic adjustment
• theoretical developments
• lateral heterogeneity
• rotational feedback
• constraints on models
• use of geodetic measurements
• regional
•  Fennoscandia
• Laurentide
• Greenland
• Antarctica
• geodetic tests of glacial isostatic adjustment models
• geometric
• site displacements
• gravimetric
• space-based (GRACE)
• ground-based (absolute and superconducting gravimeters)
• future research requirements
• future observational requirements
• terrestrial reference frame
• ground-based observations
• geometric
• gravimetric
• space-based observations
• GRACE follow-on