Christmas Island Caves

Overview

Christmas Island’s myriad caves are the result of its geological history. The island first appeared around 60 million years ago, when the peak of a volcanic basalt seamount rose from the ocean floor. Through several subsequent geological uplifts, coral reefs built up on the basalt core, creating a soft limestone cap over the island. The limestone has slowly eroded, creating a karst landscape that includes many hidden caves and underground streams and pools. The island’s caves are popular with speleologists and are an important habitat for fauna including the Christmas Island Swiftlet and rare, endemic cave species.

Two Commonwealth Government agencies currently administer the caves on the Island. Parks Australia North manages the caves found within the National Park and the wildlife in all caves while Christmas Island Administration is responsible for all caves outside of the Park. The Grotto and Freshwater Cave are the most frequently visited by local people as swimming holes and social gathering destinations, particularly The Grotto.

Technical specifications

Issue date: 9 May 2023
Issue withdrawal date: 1 December 2023
Denomination: $1.20 x 1, $2.40 x 2, $3 x 1
Stamp design: Jo Muré, Australia Post Design Studio
Product design: Jo Muré, Australia Post Design Studio
Paper: gummed: Tullis Russell 104gsm Red Phos.
Printer: RA Printing
Printing process: Offset lithography
Stamp size (mm): 37.5 x 26
Minisheet size (mm): 135 x 80
Perforations: 13.86 x 14.6
Sheet layout: Module of 50 (no design)
FDI Postmark: Christmas Island WA 6798
FDI withdrawal date: 7 June 2023

Stamps in this issue

$1.20 Freshwater Cave

Freshwater Cave is popular with cave explorers and lies on the south coast within Christmas Island National Park. It is estimated to be about 700 metres long, featuring interconnected collapse chambers, some of which contain remains of original spongework (limestone rock that has a sponge-like appearance, due to small dissolution pits created by acidic water).

The stamp photograph is by Kirsty Faulkner of Faulkner Photography

$2.40 Daniel Roux Cave

Accessible from the mainland, Daniel Roux Cave is a complex of two separate caves, located on the northern coast of Christmas Island just beyond Smith Point. The complex consists of two very different cave systems; the upper being a large multi-chamber non-technical cave that is relatively well decorated with stalagmites, stalactites, shawls, pools and helictites, and the lower cave being a deep subterranean technical cave that is has an entrance that opens into the ocean. Discovered only as late as July 1960 by a local fisherman, the cave complex was not named after its discoverer but in memory of the dead son of a Swiss draftsman who worked on the island for many years.

The stamp photograph is by Yvonne McKenzie of Wondrous World Images.

$2.40 Bishops Cave

Further to the west, also on the north coast is Bishops Cave, first recorded in 1969. It is named after speleologist Roy Bishop, who explored and mapped Christmas Island caves in the 1960s. Around 400 metres long, this cave comprises a large collapse dome and lower solutional passage (formed by acidic water seeping into and dissolving rock).

The stamp photograph is by Rauleigh Webb.

$3 The Grotto

The Grotto is on the north-east point of the island. It can be accessed via Golf Course Road, a short drive from Settlement. It’s a small, picturesque cave, around 20 metres in length, with a pool fed by both fresh water and seawater. The beautiful crystal-clear pool is popular with swimmers and tourists.

The stamp photograph is by Yvonne McKenzie of Wondrous World Images.