Finding gold is notoriously difficult with asurprisingly small-scale amountdiscovered in Earth ’s history . While some may discoverexceptionally large nugget , most go home empty - handed . In New Zealand however , one group of research worker had a brainwave : by compound the strange mixture of geology and the genetic science of fish populations they have quite literally scratch gold .
New Zealand sit on two tectonic dental plate , meaning thegeologyof the country has been forever change as heap ranges are created and rivers are altered in their course . Over the last 20 million class the drain in eastern Southland has shift considerably get changes to the distribution of alluvial amber . Also caught up in this geologic upheaval are a lowly unassuming radical of aboriginal freshwater fish in the genus Galaxias .
These fish were get living on both side of a naturally created divide known as a “ Hadrian ’s Wall ” , which separates the New Zealand arena of Otago and Southland . This stack roadblock is mostly creditworthy for the drainage change in both of these sphere and was initiated in the late Miocene or early Pliocene . The squad chop-chop realize that the Pisces the Fishes had been one population that had been split when the mountain range was created . This lead the team to wonder if they could use the fish genetic science to work out just when that rent had happened .
Three genetically dissimilar group of Pisces known as flatheads , roundheads , and pencil can be used to estimate the timing of the geologic events using a “ genetic clock ” that helps researchers find out when population become isolated and thus genetically distinct .
" There are places where the fish record is strong and the geology is n’t , and places where the geological record is strong and the fish are less informative . But by putting the two together , we can put the piece of the jigsaw puzzle together , ” biologist Jon Waters toldEos .
As the geology of the land changed , populations of these Pisces became isolated top to change in their morphology and genetics as well as forcible closing off from other population . The mountains between Southland and Otago caused this closing off leading to a Southland flathead species and then subsequent roundhead derivation . A particularly distinctive looking for and therefore strange roundhead species in the Pomahaka area take the team to mistrust that the Pomahaka River only became a tributary to the Clutha in the last million twelvemonth .
The team has gone on to use the fish as a means of auspicate where the old rivers flowed . The method acting is so successful that it has even been used across the Earth in South America . Central Otago is noted for its atomic number 79 depositary and as the rivers flowed southwards the gold was carried with it . The team made predictions establish on the Pisces populations that there is an ancient river under what is now farmland that could be loaded with alluvial Au , although as it is buried very deep the chances of extracting it are slim . And besides , if they found it , would they even beallowed to keep it ?
The newspaper is published in theNew Zealand Journal of Geology and Geophysics .
