Termitaria as Regolith and Landscape Attributes: a case study from Titania Au-Prospect, Northern Territory
A.E. Petts University of Adelaide & CRC LEME
Supervisors S.M. Hill, University of Adelaide/CRCLEME & L. Worrall, Geoscience Australia/CRCLEME
Sprigg Symposium, Adelaide 07 The Tanami Landscape
TERMITES!!!
Sprigg Symposium, Adelaide 07 Termites – Soil Engineers of the Tanami!
The presence of termite mounds (termitaria) is synonomous with the Tanami Desert - Over 14 species of termitaria have been recorded in the Tanami (Watson et al, 1993).
Detailed regolith-landform mapping and the recording of the distribution of termitariaProblem?! at Coyote Prospect Or(Petts & Hill, 2005) as well as across Titania Prospect has allowed assumptions to be made concerningpossible the relationship betweenindicator termite species and regolith-landform setting. of past These assumptions include: • Nasutitermes triodiaelandscapes?are common in ALLUVIAL regolith-landform settings • Drepanotermes rubriceps and Amitermes spp. common within COLLUVIAL and AEOLIAN regolith-landform settings
Sprigg Symposium, Adelaide 07 Aims of Presentation
Key research issues Æ What do we want to know?
QUESTION – How can we relate the spatial distribution of termitaria to the subsurface geology?
FOCUS – Interaction of mound-building termite species with specific landscape settings.
AIM – Show that termitaria may be used as palaeosurface indicators.
Sprigg Symposium, Adelaide 07 Location & Geology of the Titania Prospect
Adapted from Hendrickx et al (2001)
Sprigg Symposium, Adelaide 07 Regional Regolith Geology
October 05 Mapping Area
Adapted from Wilford, 2000
Sprigg Symposium, Adelaide 07 Regolith Geology of the Titania Prospect
Mineralisation
Aeolian
October 05 Mapping Area
Colluvial
Approximate Alluvial Palaeochannel Boundary
600000 601000 602000 603000 604000 605000
Sprigg Symposium, Adelaide 07 Simplified Regolith Geology
Main points to consider:
• 3 main types regolith- landform units; aeolian, alluvial and colluvial.
• Mineralisation occurs close to palaeochannel boundary. Watch this point! •The termites featured at Titania DO have constrained landscape preferences… Approximate palaeochannel boundary
Sprigg Symposium, Adelaide 07 Regolith-landform Attributes Termitaria have a long residence time in the landscape (Williams, 1968; Lee & Wood, 1971)
Regolith profiles are inverted through the bioturbating actions of termitaria and other soil organisms (Le Roux et al, 1991) – direct input into local surficial materials
Potential has been shown previously (Petts & Hill, 2005) for termitaria as indicators of regolith-landform setting Æ N. triodiae. - alluvial settings Æ D. rubriceps and Amitermes spp. - aeolian settings.
Sprigg Symposium, Adelaide 07 Common Mound-building Termites at Titania
Nasutitermes triodiae
Drepanotermes rubriceps
Amitermes spp. Sprigg Symposium, Adelaide 07 Spatial Distribution of Termitaria
D. RubricepsRelative Height (0.2 to 0.4m)0.2 to 0.4 m Amitermes0.5 to 0.8 spp. m (0.5 to 0.8 m)0.9 to 1.3 m Amitermes2.5 m spp. (0.9 m) & N. triodiae (1.3 m plus) Sprigg Symposium, Adelaide 07 N. Triodiae (2.5 m plus) Regolith-landform associations
Amitermes spp. PREFER mixed grasslands (both alluvial and aeolian regolith-landscape settings)
D. rubriceps PREFER well- drained, sandy soils
Sprigg Symposium, Adelaide 07 Regolith-landform associations
N. triodiae dominate the often flooded alluvial depressions proximal to the palaeochannel
(well vegetated, and mound morphology offers them protection from MOST flooding events!)
Approximate palaeochannel boundary
Sprigg Symposium, Adelaide 07 Regolith-landform associations
Is this really an anomalously located Cathedral Termite mound?
Approximate palaeochannel boundary
Sprigg Symposium, Adelaide 07 Spot the Difference…
Sprigg Symposia, Adelaide 07 Location Vs Species
Is this really an anomalously located Cathedral Termite mound?
N. Triodiae dominated areas
Relative Height 0.2 to 0.4 m 0.5 to 0.8 m Observed N. Triodiae 0.9 to 1.3 m 2.5 m Sprigg Symposium, Adelaide 07 Termitaria – Palaeolandscape Indicators!
Site location: From ToAlluvial Aeolian Floodplain Sandplain!
Sprigg Symposium, Adelaide 07 Expectations & Assumptions
We can EXPECT D. rubriceps to be present in sandplains, and N. triodiae in alluvial floodplains…
Also, we may ASSUME that their presence can assist in approximating the depth of transported cover.
THEREFORE…. The anomalously-located mound REFLECTS the nature of the subsurface geology & INDICATES that the surficial cover comprised of aeolian-sediments is not thick.
IMPLICATIONS?
Regolith-landscape attributes such as termitaria are proven indicators of past, as well as present, landscapes.
Sprigg Symposium, Adelaide 07 Acknowledgements & References Firstly, I would like to thank my supervisors, Steve Hill (especially for the use of his fantastic photos) and Lisa Worrall for all their excellent support, wisdom and guidance! Also, my research colleagues Nathan Reid, Dirk Kirste, Brad Pillans, John Joseph, Martin Smith and Tony Eggleton. Thankyou to CRCLEME and the University of Adelaide for the continued financial and in-kind support, and to the industry partners of the Tanami Collaboration Project – Newmont Asia Pacific Ltd, Tanami Gold NL, Anglo American, Geoscience Australia, Geological Society of Western Australia, and the Northern Territory Geological Survey.
References: ANDERSEN, A. & P. JACKLYN (2000). Termites of the Top End - Engineering marvels of termite mounds , CRC Tropical Savannah Environmental Protection Agency. 2005. KEBEDE, F. (2004). "Use of termite mounds in geochemical exploration in North Ethiopia." Journal of African Earth Sciences 40: 101-103. LEE, K. E. and T. G. WOOD (1971). "Physical and chemical effects on soils of some Australian termites, and their pedobiological significance." Pedobiologica 11: 376-409. LE ROUX, J. P. & B. B. HAMBLETON-JONES (1991). The analysis of termite hills to locate uranium mineralization in the Karoo Basin of South Africa. Journal of Geochemical Exploration 41: 341-347. PETTS, A. E. & HILL, S. M. (2005). The ‘ABC’ of Regolith: Attributes, Biota and their (Landscape) Context. International Geochemical Exploration Symposia Proceedings . Perth, Australia. WATSON, J. A. L. & ABBEY, H. M. (1993). Atlas of Australian Termites. Canberra, CSIRO Division of Entomology. WILFORD, J. R. (2000). Regolith- landform mapping and GIS synthesis for mineral exploration in the Tanami Region. Canberra, CRCLEME: 146R. WILLIAMS, M. A. J. (1968). "Termites and soil development near Brock's Creek, Northern Territory." Australian Journal of Science 31: 153-154. WYGRALAK, A. S. &T. P. MERNAGH (2001). Gold Mineralisation of the Tanami Region. Darwin, Northern Territory Geological Survey: 40.