Territory Stories

Report on the lands of the Ord River catchment, Northern Territory



Report on the lands of the Ord River catchment, Northern Territory

Other title

by J. M. Aldrick, D. F. Howe and C. R. Dunlop.


Aldrick, J. M.; Howe, D. F. (David F.); Dunlop, C. R. (Clyde Robert)


E-Publications; E-Books; PublicationNT; 78/24




Made available via the Publications (Legal Deposit) Act 2004 (NT).


Date:1978; Bibliographhy: p. 103.




Land use -- Northern Territory -- Ord River Region

Publisher name

Animal Industry & Agriculture Branch, Dept. of the Northern Territory

Place of publication





109 p.,[23] p. of plates : ill., maps ; 29 cm.

File type




Copyright owner

Check within Publication or with content Publisher.

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Fine textured sedimentary material is represented in the siltstones, limestones, dolomites and cherts that occur in varying proportions in the land systems Blue Hole, Frayne 1, 2, 3 and 4, Campbell 1, 2 and 3, Margery 1, 2 and 3 and in Headley 1, 2, 3, 4 and 5. The greater part of these land systems is dominated by outcrop, especially on the steeper slopes. Where gradients are below 3%, some clay soils have developed. "Floaters", surface flags of the parent rock, and areas of outcrop are commonly associated with these clay soils. In most cases rock was encountered within the 120 cm sampling depth. Grey cracking clay soils occur on more level areas of the limestones and dolomites in Campbell 3, Frayne 3 and 4 and in Headley 1. Brown cracking clays with gilgai and associated run-away cavities and surface rock'occur in small areas of Headley 1. Colluvial slopes in the more rugged areas of these land systems are typified by stony detritus and scattered outcrops. Shallow, immature red earths that are usually weakly calcareous also occur sporadically in Frayne 4 and Blue Hole land systems. Soils associated with the Negri Group of sedimentary rocks in the Hardman Basin have been described by Robinson (1971) and were not examined during this survey. The Headleys Limestone is the lowest formation in this geological group, directly overlying the volcanics of the Antrim Plateau. Headley I, 2, 3, 4, and 5 land systems are restricted to this area. All except Headley 1 are dominated by skeletal soils with outcropping limestone; Headley 3 and 4 being almost entirely outcrop. Headley 5 has skeletals on limestone on the mesa crests with skeletals on detrital volcanics on colluvial slopes below scarps. Limestone scree apparently weathers rapidly and is not common below scarps in Headley 5. Moderately deep brown and grey cracking clays with stones are limited to small valley floors between the mesas in Headley 5, and this material shows evidence of having been re-worked by seasonal water flows. (b) Soils of the Antrim Plateau Volcanics Distribution of the soils of the Antrim Plateau Volcanics is correlated with land form, which show strong structural control from the nearly horizontal lava flows. The landscape is characterised by mesas, buttes, and structural plateaux. The lava beds vary from 1.5 metres to about 50 metres thick, and the texture of the volcanic material varies from fine or coarsely crystalline basalt to highly vesicular scoria. Some areas of basaltic agglomerate occur in Agglomerate 1 and 2 land systems on plateaux and mesa tops. - 20

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