Leaena’s Breath Cave

Australian Geographic - - Geo buzz -

This 73m-long un­der­ground cham­ber has func­tioned like a mas­sive nat­u­ral pit­fall trap for hun­dreds of thou­sands of years. An­i­mals fell in, flew in or were brought into the cave by preda­tors and, un­able to es­cape, died there.

MUCH OF OUR KNOWL­EDGE of Nullar­bor pre­his­tory comes from fos­sil re­mains found in un­der­ground caves, which are char­ac­ter­is­tic of a karst land­scape due to its por­ous un­der­ly­ing lime­stone bedrock. Leaena’s Breath Cave (LBC) is one of three large caves be­neath the Nullar­bor known col­lec­tively as the Thy­la­coleo Caves. Th­ese formed more than 4 mil­lion years ago, and on­go­ing and oc­ca­sional roof col­lapses have ex­panded them into what we see to­day.

Karst caves can be palaeon­to­log­i­cal trea­sure-troves and that’s ex­actly what we have on the Nullar­bor. Their cool, dry en­vi­ron­ments and pro­tec­tion they of­fer from the el­e­ments or dis­tur­bance by an­i­mals or hu­mans can re­sult in ex­cep­tion­ally pre­served spec­i­mens. They can be used as roosts or dens, mean­ing there may be large bone as­sem­blages rep­re­sent­ing the left­overs of meals. And, as for some of the Nullar­bor caves, they may also be­come traps.

An un­der­ground cave’s pres­ence may only be be­trayed by a small hole drilled through the lime­stone by wa­ter. An­i­mals may walk, f ly or fall in, and, through in­jury, dis­ori­en­ta­tion or an in­abil­ity to climb, be un­able to make

Karst caves can be palaeon­to­log­i­cal trea­sure-troves and that’s ex­actly what we have on the Nullar­bor.

their way out again. LBC presents just such a pit­fall trap.

Its fun­nel-shaped en­trance was first doc­u­mented by caver and fos­sil en­thu­si­ast Paul Devine in April 2002 as he headed across the Nullar­bor land­scape to join a group of cavers. With the sun set­ting, he quickly tied off a rope to his four-wheel-drive, and ab­seiled down through the small open­ing to the cave f loor some 20m be­low. What Devine found was to re­write the Pleis­tocene his­tory (1.8 mil­lion–11,700 years ago) of the Nullar­bor.

A large silt f loor was lit­tered with bones. Some, along with mum­mif ied re­mains, were re­cent vic­tims of the deadly trap, but oth­ers Devine recog­nised as be­long­ing to crea­tures long gone from the Nullar­bor of to­day. Duck­ing un­der a rock over­hang, he crawled up a low pas­sage and was con­fronted by a near-com­plete skele­ton of the mar­su­pial lion, Thy­la­coleo carnifex, stretched out where it had died a lonely death from thirst or in­jury sev­eral hun­dred thou­sand years ear­lier. Sadly, Devine, who was a piv­otal mem­ber of sub­se­quent LBC ex­pe­di­tions, died in 2012. But his legacy is be­ing built upon by a team of re­searchers led by palaeon­tol­o­gist Gavin Prideaux from Flin­ders Univer­sity in Ade­laide.

1

The Nullar­bor’s Pleis­tocene land­scape may have re­sem­bled open mallee wood­land and the small cave en­trance would have been hard to spot in the veg­e­ta­tion. 2 1 3 4 5

2

This photo shows part of the cave floor from a rock­fall at the nar­row­est part of the cave. The tops of sta­lag­mites can be seen pok­ing up out of the sed­i­ment that has ac­cu­mu­lated around them.

3

Stun­ning sta­lac­tites are found in the cave. The up­per sed­i­ment in the cave and its fos­sils have been dated to at least 400,000–200,000 years old, thanks to an en­crus­ta­tion of sta­lac­tite ma­te­rial on a fos­silised skull on the cave floor.

4

Sed­i­ment on the cave floor is ex­ca­vated in 5cm lay­ers, called ‘spits’, in a grid for­ma­tion. This fine ma­te­rial, which ac­cu­mu­lated over thou­sands of years and con­tains a wealth of small bones, sits in a layer 1.5m deep atop a rock floor.

5

A so­lu­tion pipe drilled nat­u­rally through the lime­stone by wa­ter opens into the cave about 20m be­low. Here, the first per­son to doc­u­ment the cave’s ex­is­tence, Paul Devine, ab­seils through this en­trance dur­ing a 2002 ex­pe­di­tion.

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.