Geosciences Research in DML, Antarctica

Dr. G.H. Grantham, University of Johannesburg, Johannesburg

Prof. I. Meicklejohn, Rhodes University, Grahamstown

Scientific Agendas• CGG – Connecting Geology and Geophysics SCAR Action Group lead by Prof. J.

Jacobs, University of Bergen and NPI “Central Dronning Maud Land requires focused field work with ground-truthing of the new geophysical data in search of the significance of the major Forster Magnetic Anomaly and the UlvetannaLineament. ”

• ADMAP – SCAR program Geophysical database of Aeromagnetic, Gravity data of Antarctica

• Geomap – SCAR program - Updating geological Maps of Antarctica• NPI Geological Map compilation initiative• SCAR ROADMAP – Horizon Scan

DYNAMIC EARTH -‐ PROBING BENEATH ANTARCTIC ICE

35. How does the bedrock geology under the Antarctic Ice Sheet inform our understanding of supercontinent assembly and break-up through Earth history?

36. Do variations in geothermal heat flux in Antarctica provide a diagnostic signature of sub-ice geology?

38. How does volcanism affect the evolution of the Antarctic lithosphere, ice sheet dynamics, and global climate?

Current field access procedures

• Currently travel overland by skidoo + sledge from SANAE ~240kms to Troll.

• Air support 3 helicopter flights per season for fuel drops + sample and waste removal .

• Field season restricted to late December to end January.

Focus of ProjectGondwana Amalgamation and Breakup

Aeromag Aerogravity

Progress 2012-2016 Gondwana Amalgamation

Ahlmanryggen & Straumsnutane

• 2012-2013

• Structural and Geochemical study in Straumsnutane and Geochemical/-Geochronologicalstudy of Grunehogna Granite.

• Geochemistry of StraumsnutaneAndesites identical to Espungaberra lavas of Mozambique – MSc study of Neo Moabi – 1st black geologist of African descent to conduct field work and post graduate study in SANAP.

• Age of Grunehogna Granite ~1100Ma.

Sverdrupfjella• 2013-2015• Central and southern Sverdrupfjella

study on the chemistry, age and structure of granite intrusions, radiogenic isotope chemistry of basement rocks and uplift history of Sverdrupfjella and Kirwanveggan.

• 3 ages of granite sheets – younger two phases related to amalgamatianprocesses give ages of ~480Ma and 540Ma

• Basement also very variable in E-W Sverdrupfjella

• E Sverdrupfjella same as Gjelsvikfjellayounger than W. Sverdrupfjella but older than Sor Rondane.

Progress 2012-2016 Gondwana Amalgamation

• Gjelsvikfjella 2015/2016

• Central and southern Gjelsvikfjella (Near Troll) continued study on the chemistry, age and structure of granite intrusions, radiogenic isotope chemistry of basement rocks and uplift history of Sverdrupfjella and Kirwanveggan.

• Gjelsvikfjella 2016/2017

• Central and southern Gjelsvikfjella (E. of Troll) continued study on the chemistry, age and structure of granite intrusions, radiogenic isotope chemistry of basement rocks and uplift history of Sverdrupfjella and

Kirwanveggan.

Progress 2013-2016 Gondwana Fragmentation

• Study focusses on structural orientation, chemistry and age of Jurassic dykes

emplaced during fragmentation of Gondwana.

• Has possible implications for sea floor sedimentation and related gas deposits

on Mozambiqueocean floor.

• Sixty samples through Sverdrupfjella analysed with 20 Ar/Ar whole rock ages

determined.

Thank you – I have had a whale of a time!!

Active Layer Processes and Environments in the Ahlmannryggen and Jutulsessen Areas, Western Dronning Maud Land, Antarctica

Ian MeiklejohnDepartment of Geography

Rhodes University

Western Dronning Maud Land

Ahlmannryggen Jutulsessen

Mean Annual Ground Temperatures: WDML

Ground Thermal Controls

• Geology,• Substrate,• Surface Area (Ice

Effects),• Exposure Period,• Local Topography,• Regional Climate.

Relationship Between Ground Temperature, Soil Moisture & the Abundance of Maudheimia wilsoni.

Lee, J.E., Le Roux, P.C., Meiklejohn, K.I. & Chown, S.L. 2013. Species Distribution Modelling in Low-Interaction Environments: Insights from a Terrestrial Antarctic System. Austral Ecology, 38, 279-288.

Images:

J. Lee & I. Meiklejohn (2010), GeoEye (2009).

Microbial Community & PCA Analyses

Matcher, G. & Meiklejohn, I. 2014. Bacterial diversity profiles associated with patterned ground features on Antarctic nunataks. SANAP PI Symposium, Grahamstown, Rhodes University, 3-6 June 2014.

Robertskollen &Vesleskarvet Thermal Profiles

Vesleskarvet

Vesleskarvet

Robertskollen

Robertskollen

24km apart; 390m altitude difference.

Data from 2013

Images:Meiklejohn 2010

STUDENTS & COLLEAGUESJacqui DavisDavid HeddingJennifer LeeMichael LoubserJay le RouxChristel HansenWerner NelBarend van der MerweGwynneth MatcherRosie DwightDavid ScottLiezel RudolphCamilla KotzeGabrielle AyresJessica RosenfelsJenna KnoxTebogo MasebeNicola Wilmot

FUNDING

LOGISTICS

Acknowledgements