[HN Gopher] Galapagos Islands: Erosion fells Darwin's Arch
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Galapagos Islands: Erosion fells Darwin's Arch
Author : janpot
Score : 57 points
Date : 2021-05-18 07:22 UTC (15 hours ago)
(HTM) web link (www.bbc.com)
(TXT) w3m dump (www.bbc.com)
| mrtnmcc wrote:
| Are we seeing the formation of new arches at a similar rate? It
| seems we must.
| rob74 wrote:
| Good question! I guess most "new" arches start out as small and
| relatively unspectacular "windows", then grow over thousands or
| millions of years and finally collapse. So when a new arch
| forms, it doesn't turn into a tourist attraction right away.
|
| The place with probably the highest density of arches in the
| world, Arches National Park, doesn't even seem to be sure how
| many arches it has. Their homepage says "over 2000", while the
| article
| https://www.nps.gov/parkhistory/online_books/geology/publica...
| has a much more conservative estimate of 124...
| WarOnPrivacy wrote:
| Arches seem to be notable because they are the shortest part of
| the erosion process - but still last years.
|
| My take: A quickening erosion cycle could see an accelerated
| creation of arches, providing the cycle hasn't been altered eg:
| more top-down erosion.
|
| It could be that an accelerated process is still happening too
| slow to see new arches. It may also be that climate change
| isn't strongly manifesting itself this way.
| lmilcin wrote:
| > My take: A quickening erosion cycle could see an
| accelerated creation of arches
|
| I think increased erosion would also cause arches to fail
| faster (run through its lifetime at increased speed).
|
| I think there is no limit to how fast an arch can erode (ie.
| the erosion can easily speed up orders of magnitude) but at
| the same time I don't think we could be seeing orders of
| magnitude more arches created, which would be necessary to
| maintain the number of arches that are now going through
| their lifecycle faster.
|
| This lets me believe that overall increased erosion would
| cause less arches to be present at any point in time.
|
| This is just a thought experiment, I have no data to back it
| up.
| limaoscarjuliet wrote:
| I'm wondering if humans are helping the destruction. Warmer, more
| acidic ocean; more waves; more storms...
| tomhoward wrote:
| Nature running its course.
|
| I live in the same state as The Twelve Apostles, a famous group
| of limestone stacks on the coast of Victoria, Australia, south-
| west of Melbourne.
|
| Just up the road, there is a formation that was called London
| Bridge - a limestone formation protruding out from the land, with
| two stacks, making it a double-span bridge.
|
| Then one day in 1990, the bridge section adjoining the land
| collapsed. Two sightseers were on the formation at the time,
| though mercifully not on the part that collapsed; they were
| rescued by helicopter after a few hours.
|
| It just so happened that this collapse occurred during the high
| school year when we were studying limestone cliff formations in
| geography class. I remember our teacher impressing upon us that
| it was a geologically regular and normal occurrence, but
| infrequent in human life terms, so we were lucky to be able to
| observe the event just at the time we were studying the
| phenomenon.
|
| Since then they've called it London Arch [2].
|
| [1] https://explorethegreatoceanroad.com.au/the-twelve-
| apostles-...
|
| [2] https://en.wikipedia.org/wiki/London_Arch
| daveslash wrote:
| Reminds me of the 2008 collapse of Wall Arch in Arches Nat'l
| Park, Utah. https://en.wikipedia.org/wiki/Wall_Arch.
|
| Just a few days before it's collapse, I was climbing on it;
| well, I couldn't quite get to the Arch part _(so I know it 's
| collapse wasn't my fault)_, but I can't help but think: if it
| was on the verge of collapse, would it have been able to hold a
| couple of 150lb monkeys jumping around on it (my buddy and me)?
| mc32 wrote:
| I think wind forces are probably over 300lbs though perhaps
| different vectors. But who knows maybe you could have been
| the straw that would have broken the camel's back.
| rob74 wrote:
| Sad, but that's the way of the world...
|
| Honestly, I visited Galapagos in 2019 and wasn't even aware this
| arch existed. Might be due to the fact that Darwin & Wolf Islands
| are two of the smallest islands in the archipelago and located ~
| 100 km away from the rest. Plus, they are interesting mostly only
| for divers, while the other islands offer more varied attractions
| (turtles, penguins, other endemic flora & fauna, volcanoes,
| snorkeling, ...).
| arbuge wrote:
| Brings this to mind from 4 years ago:
|
| https://en.wikipedia.org/wiki/Azure_Window
|
| https://timesofmalta.com/articles/view/the-azure-window-lost...
| automatic6131 wrote:
| The azure window has gone!! I didn't know that. It's such a
| shame, because I dived it twice in my life in 2008 and 2010.
| Gozo does indeed have many other good diving spots.
| yread wrote:
| Aw man! First Azure Window on Malta now this one!
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