Rankin Island Report

Len Zell
9 July 2004

For
Dr Moya Smith - Anthropologist
Western Australian Museum - WAM

Professor Peter Flood - Dean of the Sciences - geologist
University of New England - UNE

Greg Mortimer
Aurora Expeditions - AE

With thanks to:

Mike Cusack - mapping and spotting stone 'tool pools' - Aurora Expeditions
Chris Done - cave sediment probing and mapping - Aurora Expeditions
Coral Princess Cruises - staff and equipment support
Aurora Expeditions and Australian Geographic passengers - general observations, mapping and collection support.

Preamble

During an Aurora Expeditions 'expeditionary stop' to Rankin Island in 2003 to investigate pools shown in a photograph by Damon Smith a large site of human constructed stone walls and 'pools' in the loose beach ridge rocks about 2m above present sea-level was found. Adjacent to this worked material is a small cave with possible evidence of human occupation.

As a result of this initial investigation a proposal was put to the WAM, UNE and AE to support a more intensive examination of the site and a collection of organic material from the walls, more photography, mapping and general examination of the site.

Due to the efforts of Dr Moya Smith permission was obtained from the traditional owners to undertake the proposed second investigatory visits and collection of material and data in June 2004.

Preparations were made and the AE expeditions into the area on board Coral Princess were undertaken on Thursday 10 June and Friday 25 June 2004 with the possible visits again in later July for some more specimen collection only.

Objectives

To:

1. Collect organic material from within or below the human
constructed walls for dating to assess the age of the material and indicate what earliest age the walls were constructed.
2. Collect organic material from the beach-rock strike for
dating.
3. Map the site.
4. Probe the sediments of the cave floor to assess
suitability for excavation.

Equipment

Photography - Nikon Coolpix 5000 (5 megapixel) and 8700 (8 megapixel) digital cameras on Fine settings and broom handle marked into 10cm sections as a scale.

Mapping - Garmin 12 channel and Garmin Gekko GPSs, 10m tape measure, pencils and paper.

Sediment probing - 1m 9mm threaded bar, small ball pean hammer and notepad and pen.

Organic material collection - zip-lock bags and marking pen.


Results

Organic Material Collection

Walls

Two coral specimens were taken from within the human constructed wall on the inside (away from the seaward edge) and two from the seaward side of the wall. The latter two were not integrated into the wall and could conceivably have been washed in by extreme seas or similar events and were later
discarded. All specimens were photographed in situ prior to removal.

Beach rock

As the beach rock was well below present high tide mark it was initially decided not to collect from it. On the second visit two specimens were taken from its upper and lower limits.

As the beach rock was well below present high tide mark it was initially decided not to collect from it. On the second visit two specimens were taken from its upper and lower limits.

Mapping

A map of GPS coordinates taken on each of the wall points, cave and stone tools location is attached. In addition four walk tracks around much of the site and 26 waypoints were collected on 25 June as shown on the attached aerial photos of the site. The raw data is stored on the attached CD in NMEA format 10 June and Garmin format 25 June.

Aerial view of primary site showing approximate waypoints and track positions.

Cave Sediment Probes

The floor and size of the cave were measured and photographed with a series of probes on a rough grid pattern being driven gently into the sediment. Each probe depth was measured and its location plotted on a 'mud map' of the cave floor. The maximum depth achieved was 26cm with an average of about 18cm.

Chris Done gently taps the probe into the cave floor for sediment depth assessment

The floor of the cave was fine powder littered with small slab-like ceiling material and some water worn rocks. The aspect of the cave is southerly with the floor level appearing to be 0.5-1m below the top of the stone beach ridge with the wall.

Photography

On June 10 256 and 62 images were taken of the site, cave, tools and source rocks, 'tool pools', surrounds and any interesting features and are on the attached CD. Some of these were then stitched together into panoramas which are also on the CD. Also on the CD are the images from the 2003 visit to the site.

General Observations

Whilst undertaking the mapping Mike Cusack spotted a stone axe in the base of one of the 'pool' areas and this discovery led to many stone axes, spear points, source rocks and chipped flakes being found in most of the 'pools'. Some of this material was GPS plotted and photographed. All material was left where it was found.

These 'tool pool' areas were found to be on much of the tops of the walls and lower areas near the walls throughout the whole of the island areas visited as seen on the aerial photos showing the tracks and waypoints.

As much of the site was covered in Stinking Passionfruit Vine (Passiflora
foetida) it was difficult to assess the extent of the tool pool areas. A quick assessment indicates that all the level areas had tool pools present and with worked material in them.

In addition it was found that there appeared to be 'mines' about a metre deep into the rocks at the eastern end of the wall beach wall. These may have been for tools source rocks or to dig out yam roots or similar.

Several small 'midden' sites were also observed.

There were also found the marks on the rocks indicating that a helicopter has recently landed on the site.

Recommendations

That:

1. Accurate mapping of the site be undertaken.

2. An anthropologist assess the site and excavate the cave sediments.

3. A survey of the remainder of the island be undertaken to assess its archaeological values and conservation status.

4. That included in any planning of an extensive survey will be the need for a cleaning of the site of the Stinking Passionfruit vine by fire or weed killer and fire.

5. Appropriate interpretation and management of the site be undertaken to ensure its survival.

6. That an immediate placement of some site usagerestriction be implemented to ensure the site can be controlled and damage to it minimized. This would also include permitted entry by those meeting the site management requirements.