Attachment H - Acid Sulfate Soils Assessment

                             PROPOSED COMERCIAL & RESIDENTIAL DEVELOPMENT
                             30 & 32 DOONELLA STREET, TEWANTIN

5.0      REGIONAL GEOLOGY
The 1:100,000 scale Gympie Special Geological Map (Sheet 9445 and Part 9545, DME 1999) indicates that
the site is underlain by the late Triassic to Jurassic age Myrtle Creek Sandstone (denoted as RJdm). The
Myrtle Creek Sandstone formation typically comprises quartzose sandstone, siltstone, shale and
conglomerate.
This formation is not associated with the formation or occurrence of ASS.

An extract from the geological map is shown in Text Figure 4 below. Brown stippling indicated on the
geology map is indicative of a deep weathering profile, whereby the rock strata have generally weathered to
soil materials (typically clays for this unit) over geological time.


                                                                          RJdm - Myrtle Creek Sandstone

                                                                          Age         Late Triassic - Early Jurassic

                                                                                      Quartzose sandstone,
                                                                          Lithology   siltstone, shale conglomerate,
                                                                                      coal; weathered

                                                                          Dominant
                                                                                      ARENITE-MUDROCK
                                                                          Rock




Text Figure 4: Extract from Gympie Special Geology Map


6.0      GEOTECHNICAL SITE INVESTIGATION
A geotechnical investigation for the proposed development was completed by Tectonic in June 2018
(Tectonic Report No. 18151-001 Rev0). Site investigation comprised the drilling of five boreholes using a
4WD mounted rotatory drill rig to depths of between 3 m and 6 m below ground level (BGL).
The encountered subsurface conditions typically comprised:

       Fill Material – typically comprising 0.25 m to 0.75 m depth of loose to medium dense silty/clayey
        sands and gravels; overlying

       Inferred Residual Soil – comprising stiff to very stiff, natural silty/sandy/gravelly clays derived from
        weathering of the Myrtle Creek Sandstone to borehole termination.

Standing groundwater and/or seepage was not encountered in any of the boreholes at the time of
investigation.




26 May 2021
Report No. 18151-002-Rev0                                4