Posted by: cousindampier | 30 January 2011

Glaciers, Mountains, and Seas: A novice geological history

I made it to the Franz Josef Glacier on Friday.  There is a hotel here I’ll be working at for the next two or two and a half months, in the laundry room.  However, on the nine-hour bus ride from Nelson to Franz Josef, I got to see my first glimpse of the Tasman Sea and the Southern Alps.

Really, my entire experience in New Zealand has been one gorgeous sight after another.  Starting in Wellington with the harbour, moving to Nelson and hiking a mountain overlooking the city, and driving down the west coast, one of the most amazing features of New Zealand if not the most, was an unintentional but fortunate way to start a journey.

The drive down the west coast moves from the flatlands and vineyards of the Marlborough region to a river valley to a very winding road along the coast.  All of these regions were formed as New Zealand split from Australia and drifted to the east.

The following is a rough outline.

Laurasia-Gondwanaland - Thanks Wikipedia!

Most everybody knows Pangea, the last supercontinent.  Pangea eventually split into two continents, Laurasia, which contained most of the landmass of North America and Eurasia (minus the important area now called India) and Gondwanaland, which contained South America, Africa, Antarctica, Australia, New Zealand, and India.

Eventually, the landmass of South America broke away, drifting west; the others drifted east.  Another split occurred in which the landmasses of Australia, Antarctica, India, and New Zealand split from Africa; and then Antarctica and India split from the Australia and Zealandia masses.

New Zealand lies on its own continental shelf, called Zealandia.  Most of Zealandia lies under the ocean, but the landmass is comparable in size to Greenland.  A fault line runs directly in the middle of this continental shelf – where the islands of New Zealand stand exposed.  The North Island is part of the Australian plate, while the southern is mostly part of the Pacific plate.  Where these two plates meet are the Southern Alps.

Abel Tasman, via Wikipedia

The Southern Alps were first noted by Abel Tasman, and further described in detail by James Cook.  This will be a pattern in most of New Zealand history – Tasman was the first to discover, but Cook was the first to chart, describe, sample, and bring into reality for much of Europe.  Tasman’s voyage, while not ignored, was partially kept hidden by the Dutch for political reasons, and otherwise unreliable – until Cook’s first voyage, no navigator had an accurate way to calculate longitude, meaning many of the islands of the Pacific were charted far from their actual position.

The Alps are important for Franz Josef for three reasons.  First, they provide absolutely stunning scenery.  It is continually stunning to be in the area, because the cloud cover shifts frequently and changes the view one has of the mountains constantly.  Second, without the Alps, there is no Franz Josef Glacier.  Third, much like the Olympic Mountains in Washington, the Alps make for an effective barrier to rain clouds, meaning the township of Franz Josef is in a rain forest while simultaneously promoting a very cold feature of the mountains.

A little more than midway down the southern island lies Franz Josef Glacier, and further the Fox Glacier.  Named after the Austrian Emperor, Franz Josef descends the Southern Alps to around 900 feet above sea level and during the last ice age, ran out to sea.  It is also getting larger, in contrast to nearly every other glacier in the Southern Alps.

Glaciers disrupt everything they flow over, forming incredible features on a landscape.  The walk to Franz Josef is over what seems to be a vast riverbed, but is actually the glacial bed, formed when the glacier extended much further towards the sea.  It is an amazing landscape of gravel, boulders, and shale, with a number of small waterfalls dropping nearly vertical, as the hills and mountains are steep.

Cptn. James Cook (via Wikipedia)

The glacier used to flow into the Tasman Sea, named after that same Abel Tasman.   It was mapped by James Cook, largely during his first two voyage – he is immortalized via Cook Strait, which runs between the North and South islands of New Zealand, and by nearly every named geological feature in New Zealand, as Cook visited the islands six times over four years, extensively mapping the area.

The Tasman Sea is important for any number of reasons, but two predominate.  First, it makes New Zealand not a part of Australia.  New Zealand separated from Australia early enough to remain a fairly pristine environment.  Unlike Australia, New Zealand never had natural mammalian predators.  A large number of flightless birds inhabit the islands, because there was never anything to hunt them until Europeans showed up and brought dogs, stoats, and possums.   The forests of the southwest, around the Fiordland area, are as similar to the Jurassic period as any on earth.

Second, the interplay between the Tasman Sea and the Southern Alps gives the west coast its beauty.  New Zealand sticks down into the ‘roaring forties’ – the latitude between forty and fifty degrees south latitude which has strong westerly winds (meaning they push any ship using sail east).  This is one of the key reasons New Zealand wasn’t ‘discovered’ for so long – no voyage setting out from Chile was able to reach the islands, and Dutch and British navigators used the winds to get to Batavia in Indonesia, and moved north far too early.

The west coast is a gorgeous place due to the interaction of these three features.  It is a World Heritage Site, and for good reason.  It is absolutely a gorgeous place.

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