The wo­man who dates Hob­bits and gi­ant apes

Cosmos - - Spectrum - BELINDA SMITH is a sci­ence and tech­nol­ogy jour­nal­ist based in Mel­bourne, Australia.

At the bot­tom of a pit dug three me­tres into a cave floor, Kira West­away sat on a box, me­thod­i­cally push­ing hol­low tubes into the sur­round­ing dirt and pulling them out.

It was July, 2003. The cave, named Liang Bua, was nes­tled in dense trop­i­cal jun­gles on Flores, an is­land at the east­ern end of the In­done­sian ar­chi­pel­ago. Less than a year ear­lier, West­away was a scuba in­struc­tor in Thai­land with a suc­cess­ful busi­ness. Now she was a PHD stu­dent, spend­ing her time scoop­ing sub­ter­ranean sed­i­ment sam­ples. She planned to take the morsels of earth back to Australia to find out how old they were – and, by ex­ten­sion, the age of any arte­facts found in the lay­ers.

What she couldn’t plan for was what would be dis­cov­ered the next day. A tiny skele­ton be­long­ing to a new ho­minin species – Homo flo­re­sien­sis – would be un­earthed just 20 cen­time­tres un­der­neath the very spot she was sit­ting.

When re­vealed to the world, the “Hob­bit” – as it was dubbed – would up­turn our knowl­edge of hu­man evo­lu­tion and mi­gra­tion and be mired in years of con­tro­versy. Sci­ence magazine would pro­claim the bun­dle of bones the sec­ond-most im­por­tant find of 2004 (af­ter the dis­cov­ery of wa­ter on Mars).

But that was to come. In the cool calm of Liang Bua, the stu­dent con­tin­ued col­lect­ing her sed­i­ments, bliss­fully un­aware of the wild ride that lay ahead.

Hav­ing spent most of her life in Asia and Australia, West­away is now based at Mac­quarie Univer­sity in Syd­ney, but a lin­ger­ing ac­cent be­trays her birth coun­try: Eng­land. As an un­der­grad­u­ate she was fas­ci­nated by the nat­u­ral ge­og­ra­phy of Earth, thanks to a pas­sion­ate teacher. She em­barked on a sci­ence de­gree at the Univer­sity of Liver­pool, and a third-year sub­ject in qua­ter­nary sci­ence got her well and truly hooked.

The Qua­ter­nary era – the past 2.6 mil­lion years – is marked by cy­cles of vast ice sheets and glacia­tion mov­ing as far as 40 de­grees lat­i­tude from the poles (cov­er­ing Tas­ma­nia in the south, and New York in the north). “I re­ally got into that,” she says. “Work­ing on glaciers in Nor­way in cram­pons, do­ing that hard, crazy stuff – it was awe­some.”

She fol­lowed her first de­gree with a masters in qua­ter­nary sci­ence at Royal Hol­loway, part of the Univer­sity of Lon­don. It was there that she dis­cov­ered lu­mi­nes­cence dat­ing.

This mea­sures the amount of light that shines from min­er­als such as quartz and feldspar when they’re heated or il­lu­mi­nated. The bright­ness of the emit­ted light de­ter­mines when the sam­ple was last heated or ex­posed to sun­light.

Con­sider a grain of quartz on the ground. Over time, elec­trons en­er­gised by the de­cay of cos­mic ura­nium, potas­sium and tho­rium iso­topes be­come lodged in the quartz crys­tal lat­tice. When the grain is ex­posed to sun­light, that energy vi­brates the lat­tice, re­leas­ing the elec­trons in a burst of light and “re­set­ting” the clock to zero.

But if the quartz is washed into a cave by a stream, or blown in by wind and buried, it con­tin­ues to ac­cu­mu­late elec­trons with­out be­ing “re­set”. The longer the grain is buried, the more elec­trons it col­lects and the brighter it glows when it is dug up by ar­chae­ol­o­gists and ex­posed to light again in a lab­o­ra­tory.

This is the un­der­ly­ing prin­ci­ple of op­ti­cally stim­u­lated lu­mi­nes­cence dat­ing. Ther­mally stim­u­lated lu­mi­nes­cence dat­ing is sim­i­lar, but mea­sures the last time the sam­ple was heated to around 400 to 500 °C.

Lu­mi­nes­cence dat­ing is of­ten used in con­cert with ra­dioiso­tope dat­ing, which re­lies on com­par­ing the ra­tio of iso­topes in a sam­ple to nut out how old it is. Car­bon dat­ing, for in­stance, mea­sures the amount of car­bon-14 in a sam­ple, which de­cays by half ev­ery 5,730 years. Af­ter around 50,000 years, there’s very lit­tle car­bon-14 left to de­tect.

This is where lu­mi­nes­cence re­ally shines: it can mea­sure up to hun­dreds of thou­sands of years. This means it is much more use­ful for dat­ing arte­facts and bones from the Qua­ter­nary era, which roughly marks the emer­gence of our ear­li­est Homo an­ces­tors.

Say you find a stone tool in an ar­chae­o­log­i­cal dig, West­away says. With­out know­ing how old it is, you can’t say much about it. But us­ing lu­mi­nes­cence dat­ing, you could find out when it and its sur­round­ing sed­i­ment was buried. “Sud­denly you put an age to the stone tool and it could be the old­est stone tool on the con­ti­nent, or the first ev­i­dence that hu­mans were mak­ing tools.

“Dat­ing just puts that con­text, that mean­ing, on it. It re­ally is a huge game-changer.”

Af­ter her masters de­gree, a dream PHD project popped up: based in Lon­don and as­sign­ing dates to sites in the Hi­malayas. But she didn’t get it. She was so put out, she says, she al­most left the re­search realm for good. “But then I thought: If I drop out, is academia go­ing to suf­fer? Prob­a­bly not. But will I suf­fer? Yes! It’s my dream.”

So she did the re­search equiv­a­lent of cold-call­ing, send­ing her CV out to labs around the world. It worked. Shenghua Li from the Univer­sity of Hong Kong of­fered her a schol­ar­ship to do a masters in op­ti­cal dat­ing of quartz, where she’d also an­a­lyse and date an­cient sand dunes in South­ern China.

It sounded per­fect, yet West­away didn’t know what to do. Her fa­ther had died the year be­fore and she didn’t want

to leave her mother. But when she asked her mum for ad­vice, “she self­lessly said, ‘do it’. So I left at 21 and I lit­er­ally haven’t lived in Eng­land again since”.

So be­gan the Asia ad­ven­tures. Af­ter fin­ish­ing her sec­ond masters – and be­ing in her mid-20s – West­away took a break. She trav­elled and be­came a scuba in­struc­tor, tak­ing divers ex­plor­ing reefs and wrecks.

Still, the idea of a re­search ca­reer re­mained squir­relled away in her mind. She was run­ning a scuba div­ing shop in Thai­land when she “had this thought that I wanted to do my PHD be­fore I was 30”, she says. “So I did the ‘CV around the world’ thing again, be­cause it worked so well the first time.”

This time, Robert “Bert” Roberts at the Univer­sity of Wol­lon­gong an­swered the call. His project was dig­ging up the floor of a cave in In­done­sia. He needed some­one with lu­mi­nes­cence dat­ing ex­pe­ri­ence – and she’d be per­fect for it.

West­away had never been to Wol­lon­gong so Roberts urged her to have a look at the univer­sity web­site. It de­scribed a cam­pus nes­tled by Mt Keira – not an ex­act match to “Kira” but “it was the weirdest thing and I knew I had to do it”. She gave up the dive shop and moved to Australia.

A few months later, West­away, Roberts and their In­done­sian and Aus­tralian col­leagues were traips­ing through the In­done­sian jun­gle on the trail of Dutch mis­sion­ary Theodor Ver­ho­even. Ver­ho­even taught at a sem­i­nary on Flores in the 1950s and 1960s, but he was also an ac­com­plished am­a­teur ar­chae­ol­o­gist. Dur­ing his as­sign­ment, he un­cov­ered mod­ern hu­man graves, stone tools and an­cient an­i­mal fos­sils in nu­mer­ous caves on the is­land.

When Ver­ho­even left to re­turn to Europe, ar­chae­ol­o­gist Raden Soe­jono con­tin­ued ex­ca­vat­ing the sites. He found more fos­sils and tools, but could only dig to around three me­tres be­fore the walls of the pits be­came un­sta­ble and prone to cav­ing in.

Roberts and his ar­chae­ol­o­gist col­league Mike Mor­wood wanted to dig as far as pos­si­ble – down to the very bedrock it­self – but re­alised they would have to learn the right tech­niques to keep the sites safe. So they com­pleted a gravedig­ging course in Syd­ney, learn­ing how to shore the sides of the pits with wood.

They took that tech­nique to In­done­sia, taught it to the lo­cal ar­chae­o­log­i­cal team lead­ing the ex­ca­va­tion and bingo! They could safely dig fur­ther than be­fore. The deeper they dug, the fur­ther they peeled back the lay­ers of hu­man his­tory.

Caves are nat­u­ral shel­ters and can be used by gen­er­a­tions of hu­mans and other ho­minins who lived, cooked and died there. Dust and dirt cov­ered scraps of cooked bone or dis­carded tools – if they weren’t buried on pur­pose – and locked them away un­der lay­ers of com­pacted earth. There they could re­main, safe from dis­tur­bance – un­til the ar­chae­ol­o­gists came along.

West­away’s task was to as­sign dates to the lay­ers of sed­i­ment laid down in the cave over the mil­len­nia and give con­text to any ob­jects they found.

She ar­rived in March 2003. It was her first dig. While she’d been in caves be­fore, she wasn’t pre­pared for Liang Bua, which means ‘cool cave’. “You just get this un­be­liev­able awe when you walk in,” she says. “It could be drip­ping wet and hot out­side, and you walk into this cave and it’s re­ally cool and calm and has this lovely feel­ing about it.”

The cave is a nat­u­ral hall, with a tall ceil­ing and flat floor. Most re­cently, Dutch mis­sion­ar­ies used it as a school. One of West­away’s col­leagues on the dig, In­done­sian ar­chae­ol­o­gist Rohkas Awe Due, even had lessons there as a kid. “And no won­der,” West­away adds. “It’s such a nice place to hang out.”

But in Liang Bua in 2003 the ar­chae­ol­o­gists wanted to find ev­i­dence of Homo sapi­ens’ mi­gra­tion to Australia from Asia. In July, West­away took her fi­nal sam­ples, jumped on a plane back to Australia and walked into Roberts’ of­fice the next day. She greeted him with: “Hey! I’m back!” Roberts replied: “Oh my god! They’ve found a skele­ton.”

Be­tween her fly­ing out of Flores and ar­riv­ing in Wol­lon­gong, the In­done­sian re­searchers had dug two me­tres fur­ther, find­ing ev­i­dence of fire, re­mains of a now-ex­tinct ele­phant-like crea­ture called a Ste­godon – and the skele­ton of a small ho­minin.

None of the Western re­searchers were there at the time – just the In­done­sian crew. “I’m glad it was them that found it and not us,” West­away says. “It was their dis­cov­ery.”

The skele­ton was un­veiled in Na­ture in Oc­to­ber 2004: an al­most com­plete skull along with leg, pelvis, hand and foot bones. The crea­ture was prob­a­bly fe­male, around 30 years old when she died. While she stood just a me­tre tall, her feet were large for her body size – thus, H. flo­re­sien­sis’ nick­name “Hob­bit”, af­ter JRR Tolkien’s short-statured, big-footed

he­roes of The Lord of the Rings.

West­away’s sed­i­ment anal­y­sis pegged the Hob­bit’s life at 38,000 to 18,000 years ago – over­lap­ping with H. sapi­ens, who ar­rived in In­done­sia about 45,000 years ago, ac­cord­ing to the ev­i­dence at that time

And then de­scended the me­dia at­ten­tion. The spec­i­men’s story was cov­ered by Time, Der Spiegel, the BBC and Na­tional Ge­o­graphic. But so too came the doubters. Rather than a new species, some claimed, the Hob­bit was noth­ing more than a dis­eased mod­ern hu­man – per­haps suf­fer­ing mi­cro­cephaly, which could ex­plain her grape­fruit-sized head. Oth­ers thought she might be a dwarf.

An iden­ti­cal jaw­bone un­cov­ered in fur­ther Liang Bua ex­ca­va­tions in 2004 – and re­ported in Na­ture the fol­low­ing year – threw cold wa­ter on these the­o­ries. The orig­i­nal Hob­bit and the sec­ond mandible’s owner lived 3,000 years apart. The odds of them both suf­fer­ing the same head­shrink­ing dis­or­der were in­cred­i­bly small.

Re-ex­ca­vat­ing the cave in the years fol­low­ing also changed the time­line. Pe­cu­liar ero­sion pat­terns, not no­ticed in the ini­tial ex­ca­va­tions, meant the one sed­i­ment layer could be tens of thou­sands of years older than the layer di­rectly above it.

Dur­ing her first visit to Liang Bua – just be­fore the Hob­bit was un­earthed – West­away had in­ad­ver­tently col­lected 50,000- and 18,000-year-old sed­i­ment lay­ers in her tubes. When she mixed the sam­ples and dated them, she ended up with an av­er­age age: around 36,000 years.

But the Hob­bit lay in the older bank of sed­i­ment. It turns out the lit­tle ho­minin lived be­tween 100,000 and 60,000 years ago – a rev­e­la­tion re­ported in Na­ture in 2016. Whether H. flo­re­sien­sis as a species over­lapped with mod­ern hu­mans is still open for de­bate.

Post-hob­bit, West­away didn’t rest on her lau­rels – far from it. Her work took her far­ther afield in south­east Asia and Australia again – not div­ing this time, but piec­ing to­gether the cli­mate at the time of the Hob­bit and its an­ces­tors.

In Pu­nung in East Java, the wood­land en­vi­ron­ment sud­denly turned warm and trop­i­cal – il­lus­trated by Ste­godon, which pre­ferred a more open habi­tat, be­ing re­placed by rain­for­est-dwelling orang­utans and sun-bears in the fos­sil record. When that cli­matic shift oc­curred had only been roughly es­ti­mated – un­til West­away and Mor­wood ar­rived on the scene.

Mor­wood spot­ted a flow­stone – a flat, lay­ered rock built up by mil­len­nia of min­eral-rich wa­ter flow­ing over it, leav­ing mi­nus­cule de­posits. “They’re awe­some to date,” West­away says. “They give you a min­i­mum age for the sed­i­ment they cap. With­out flow­stones, I wouldn’t get half the ev­i­dence I get to­day.”dat­ing flow­stones from the area along with brec­cia – jagged frag­ments of rock and fos­sils ce­mented to­gether – she and her col­leagues (many of whom were on the orig­i­nal Hob­bit dig) con­cluded the cli­mate turned trop­i­cal be­tween 118,000 and 128,000 years ago.

So what does this mean for ho­minins at the time? Java is fa­mously the site of the first Homo erec­tus fos­sils, dis­cov­ered in 1891 by Dutch palaeoan­thro­pol­o­gist Eugene Dubois. But Dubois also found teeth, at­trib­uted to H. sapi­ens, in brec­cia from a Su­ma­tran cave called Lida Ajer.

West­away and her col­leagues re­dis­cov­ered the cave, con­firmed that the teeth were in­deed mod­ern hu­man and dated the ev­i­dence. This re­search, pub­lished in Na­ture in Au­gust 2017, sug­gests that H. sapi­ens made it all the way to Asia by 73,000 to 63,000 years ago – some 20,000 years ear­lier than pre­vi­ously thought.

In 2013, as the his­tory of the Hob­bit and its an­ces­tors was be­ing brought to life, Mor­wood passed away, a year af­ter be­ing di­ag­nosed with cancer. His death hit West­away hard.they had first met at a ho­tel in Ruteng, a town 10 km south of Liang Bua, the day be­fore she set foot on the site. She was “young, fit, en­thu­si­as­tic, feisty and in­ap­pro­pri­ately dressed in hip-hug­ging jeans, bare midriff and skimpy top”, Mor­wood wrote in his 2007 book, A New Hu­man: The Star­tling Dis­cov­ery and Strange Story of the ‘Hob­bits’ of Flores, In­done­sia. Be­ing a tra­di­tional Catholic area, work­ers at Liang Bua put down their tools and stared.

Mor­wood couldn’t have the ex­ca­va­tion dis­rupted when­ever West­away was on site – be­sides, those clothes were an oc­cu­pa­tional health and safety night­mare – so had a quiet word to her. The next day, she showed up to work in long baggy trousers and long-sleeved shirt. “Things quickly set­tled down and she proved a very com­pe­tent and hard­work­ing re­searcher,” Mor­wood’s book records.

He quickly be­came her men­tor, but the teach­ing ran both ways. West­away didn’t spend all her time in the cave; she spent a con­sid­er­able amount of it out and about, ex­plor­ing the sur­round­ing land­scape. This, Mor­wood thought, was a waste of time – to him, the im­por­tant stuff was in the cave – un­til West­away ex­plained that fig­ur­ing out when and how Liang Bua formed gave the ar­chae­ol­o­gists a max­i­mum date of oc­cu­pa­tion and that all-im­por­tant con­text for the ev­i­dence.

Even in his fi­nal days, Mor­wood had myr­iad projects and pa­pers on the go. More than four years af­ter his death, his name still ap­pears in jour­nals. He is in­cluded in the list of au­thors on West­away’s Au­gust Na­ture pa­per. “I’m not just be­ing re­spect­ful of his mem­ory,” she says. “He was an in­te­gral part of the re­search.”

When we spoke (in July, 2017), West­away had just re­turned from a trip to China. She had been in­vited to work

on Gi­gan­to­p­ithe­cus blacki – an ex­tinct gi­ant ape that, from just a few teeth and a cou­ple of mandibles, palaeon­tol­o­gists think stood three me­tres tall and weighed half a tonne. “I of­ten say I’ve moved from the small­est hu­man on the planet to the largest ape,” she laughs. “If you men­tion to a palaeon­tol­o­gist that you work on ‘Gi­ganto’, they all love it,” she adds. “It’s such a mys­tery.”

The mys­tery? Gi­ganto died out 300,000 years ago, a time when many other apes (in­clud­ing hu­mans) were flour­ish­ing. West­away wants to find out why it dis­ap­peared when it did.

Mean­while, she runs the lu­mi­nes­cence lab­o­ra­tory and teaches at Mac­quarie, a post she’s held since 2008. “If you do lu­mi­nes­cence, peo­ple will al­ways want you to do re­search with them,” she says. “I get in­vi­ta­tions to work with ar­chae­ol­o­gists, palaeon­tol­o­gist, bi­ol­o­gists, ge­ol­o­gists. Any­one who works with sed­i­ment needs to know the age of things. It just opens up all these op­por­tu­ni­ties.”

While West­away has dipped in and out of academia – years of div­ing in Thai­land, for in­stance – she has no re­grets. “Peo­ple think it was a U-turn but it ac­tu­ally fits in re­ally well with what I’m do­ing now be­cause all my work is in Asia,” she says. Her ad­vice to younger re­searchers is it’s im­por­tant to re­mem­ber that ca­reer pro­gres­sion is rarely a set of sim­ple steps: “You have to be aware that you’ll go on weird tan­gents. Things aren’t go­ing to go to plan, but you’ll get to where you want to go even­tu­ally, even if it takes 20 years.”

West­away be­gan her work in Asia us­ing lu­mi­nes­cence dat­ing of quartz to an­a­lyse sand dunes in South­ern China.

A hu­man tooth (top left) from the Lida Ajer cave found by Eugene Dubois in 1891, com­pared to an orang­utan tooth (right). Us­ing dif­fer­ent tech­niques, West­away and her col­leagues have dated the pres­ence of ho­minins in the cave to 73,000 to 63,000 years ago.

Newspapers in English

Newspapers from Australia

© PressReader. All rights reserved.