Craters on Earth and the other Planets

[Turtle]

Hello Turtle

 

I know the Hawaii islands are not on the boundry of plates. They are at a hot spot created by convectional currents created by the movement of the oceanic plate folding down and under. This convectional current takes oceanic floor material withit and realeasing it via the volcanoes.

 

Making silly comments does not make you right.

 

I'm here to discuss issues not to go into some form of silly conflict of words.

 

Old ideas,,,,,,,,,,,very funny

 

Hello Harry,

Yes there is convection, but no to the mechanism you describe as driving the convection. The oceanic plate, that is the Pacific Plate is only folding under other plates at the boundaries, and then at other boundaries it does not go under at all, but slides along. That is a strike slip boundary and the San Andreas fault is one such.

Not only do you have a mistaken concept of hot spots in the ocean, that mistaken concept disregards Yellowstone's hot spot.

The issue is, you have many of the correct terms, but you have given them in mistaken circumstance. I do not take matters of fact as 'silly conflicts of words'. You gave the wrong figure for the life of ocean plates, and likewise you give the wrong description as I just described. Moreover, you have provided no links or supporting material for your statements or acknowledged your error(s).

My jests are just some sweetner for the bitter facts. :confused:

[Eclogite]

Turtle,

I am not sure what you feel is incorrect in Harry's description of plate tectonics. I think his four hundred year figure was a simple slip of the tyepwriter keyboard - I believe he menat four hundred million, which is the right close order of magnitude.

Also his description of plate movements and hot spots, basic as they are, do not appear to be in conflict with current theory. Perhaps I am missing something?

I agree Harry (sorry Harry) can be very vague in his statements, but I just don't think he is too far out here.

 

(Of course I am assuming that when he writes They are at a hot spot created by convectional currents created by the movement of the oceanic plate folding down and under. he actually means They are at a hot spot created by convectional currents which are also moving the oceanic plates and folding these down and under at plate boundaries.

[Turtle]

Turtle,

I am not sure what you feel is incorrect in Harry's description of plate tectonics. I think his four hundred year figure was a simple slip of the tyepwriter keyboard - I believe he menat four hundred million, which is the right close order of magnitude.

Also his description of plate movements and hot spots, basic as they are, do not appear to be in conflict with current theory. Perhaps I am missing something?

I agree Harry (sorry Harry) can be very vague in his statements, but I just don't think he is too far out here.

 

(Of course I am assuming that when he writes They are at a hot spot created by convectional currents created by the movement of the oceanic plate folding down and under. he actually means They are at a hot spot created by convectional currents which are also moving the oceanic plates and folding these down and under at plate boundaries.

 

Thanks Eclo! You are the go-to guy, and may well be correct. If Harry stops laughing long enough, perhaps he will affirm your explanation.

 

Besides typos, vaugeness, etc., I take contention with Harry's implication that the origin of hot spots is known simply because there is convection below them. What I am getting at is that the mechanics of the convection are not known, that is to say we don't know why a hot spot should form away from a plate boundary in a particular place.

 

Just waking, so I'll get back to this later. Again your help is appreciated.:) :)

 

PS Eclogite, what do you think of my wild speculation that an impact may create a hot spot?

[Turtle]

While not about craters, I have an article that goes to the points of plate mechanics and what we don't know, as well as the use of old information no matter how well recalled. Science is always ammendable. :hyper:

 

 

A section of the Appalachian Mountains discovered in Mexico is forcing scientists to redraw their maps of ancient Earth.

 

http://www.msnbc.msn.com/id/15774076/

[Harry Costas]

Hello All

 

Hello Eclogite, mate you are correct. The oceanic floor is only a few hundred million years old. Typo error.

 

The convectional currents that I speak off can be found in text books.

Turtle does not understand.

 

Oh! yes if I want to smile. So what!!!!!!!!!!!

 

Some people make me laugh the wrong way.

[Turtle]

Besides space-rock impacts and volcanoes, steam/expanding gas explosions cause cratering on Earth and other planets. I have visited one in Oregon called 'Hole in the Ground' (clever name, eh!?:cocktail: ) Looks for all the world like a smallered 'Meteor Crater' in Arizona. I'll be back with at least a few links to support these claims. :esmoking:

 

Post Script Link(s):

Hole in the Ground:

http://www.fs.fed.us/r6/centraloregon/geology/info/volcanoes/holeground.shtml

Course on cratering:

http://pangea.stanford.edu/courses/gp025/webbook/10_groundzero.html

[Harry Costas]

Hello Turtle

 

I agree with you craters can be created by other means.

 

Sometimes when the volcanoe explodes it leaves behind a giant creater hundreds of meters deep.

[Turtle]

Hello Turtle

 

I agree with you craters can be created by other means.

 

Sometimes when the volcanoe explodes it leaves behind a giant creater hundreds of meters deep.

 

Mt. Mazama did just that about 7,000 years ago and formed Crater Lake in Oregon.

http://volcano.und.edu/vwdocs/volc_images/north_america/crater_lake.html

 

Then we have Mt. St. Helens, which is just 40 miles from me, that blew out laterally to the surprise of geologists. It has continued errupting for over a year now as it rebuilds itself.

http://hypography.com/forums/earth-science/6546-mount-st-helens.html

 

Then we have Long Valley Caldera that Buffy lives near:

http://hypography.com/forums/earth-science/8913-supervolcanos.html

B)

PS Looking at your initial post Harry, I wonder are we just trading facts or do you have a point to make?

[LaurieAG]

Then we have Long Valley Caldera that Buffy lives near:

http://hypography.com/forums/earth-science/8913-supervolcanos.html

 

Hello Turtle,

 

I live near the (dormant) Richmond caldera in Australia.

 

Here's a bit of a thought experiment for you Turtle. All of the disaster movies show an asteroid/comet etc racing towards earth and massive destruction etc. While this may be one possible scenario, how about a situation where a relatively stationary (or slow moving) asteroid gets pulled directly into our planets orbit path around our sun.

 

As our planet would actually be moving towards the space rock and not vs a vs, wouldn't you expect at least one (or a series of) bounce dent(s) (probably appearing as lakes on land), that follow a trajectory that is a result of the combination of their own initial trajectory and the earths rotation, which ends in a large rock?

 

Anything that fell in from 'above' would curl one way (straight line from lake to rock) while anything that fell in from below would curl the other way. One common ratio seems to be (for something falling from above) that the rock will be 7 units down and 2 across from the bounce lake. At least that seems to be a common factor between lakes and rocks (and several key global religions).

[LaurieAG]

I may as well continue (web page glitch double up).

 

And you mustn't forget that craters and rocks may not be the only things that you find at the end of, or along these paths. Large mineral deposits can be another possible payload (some of the larger gold nuggets look very much like molten gold 'shot' into wet sand). Croagh Patrick (mount St Patrick) in Ireland contains the only commercially mineable gold deposit remaining in the country. A couple of years ago a company called Dragon Mining gained a gold lease in one of the scandinavian countries. The concerns over disturbing reindeers was countered by the fact that the company was only going to go and pick the deposit up off the ground and place it into trucks.

 

I worked at Elura mine in western New South Wales in the 80's. In a relatively straight line there are 3 major deposits (and mines). In Cobar there is the old open cut Great Western mine that held copper and lead. 5 miles out there is the underground CSR lead/zinc mine that has a relatively shallow deposit. Finally, around 40 miles out, there is the Elura underground lead zinc mine with the largest deposit in the southern hemisphere (at around 1 mile or so underground).

[Turtle]

Hello Turtle,

 

I live near the (dormant) Richmond caldera in Australia.

 

Here's a bit of a thought experiment for you Turtle. All of the disaster movies show an asteroid/comet etc racing towards earth and massive destruction etc. While this may be one possible scenario, how about a situation where a relatively stationary (or slow moving) asteroid gets pulled directly into our planets orbit path around our sun.

 

As our planet would actually be moving towards the space rock and not vs a vs, wouldn't you expect at least one (or a series of) bounce dent(s) (probably appearing as lakes on land), that follow a trajectory that is a result of the combination of their own initial trajectory and the earths rotation, which ends in a large rock?

 

Howdy Laurie. Interesting proposition. I'm not the one to compute that possibility exactly, but I have some speculations. If the incoming rock was descending at a steep enough angle to bounce off Earth, it probably would skip off the atmosphere first. If the incoming rock is 'slow' it may get thrown off by the gravity, in the way we use the planets to sling-shot our exploratory satellites, or possibly be captured into an Earth orbit. (This happens quite a bit we are finding, that is, asteroids come in, go into orbit around Earth a while, and then they get flung off again. Corkscrew Asteroid Article )

Is the skipping meteorite your idea or have you seen it from others? :eek_big:

[LaurieAG]

If the incoming rock is 'slow' it may get thrown off by the gravity, in the way we use the planets to sling-shot our exploratory satellites, or possibly be captured into an Earth orbit. (This happens quite a bit we are finding, that is, asteroids come in, go into orbit around Earth a while, and then they get flung off again. Is the skipping meteorite your idea or have you seen it from others? :cup:

 

Hello Turtle, my idea isn't quite like quasi moons (asteroid or artificial) that rotate around both the sun and our planet, and it isn't really like skipping stones either (even though they are possible trajectories).

 

I suppose it wouldn't be like an asteroid coming in either, but more like the earths gravitational field moving (and rotating) onto a relatively stationary object in its path. There wouldn't be that much rotation as the object isn't being captured by our planets gravity and the whole process would be more like pushing something like an exercise ball onto a fixed object i.e. the gravitational field would act like a cushion on the asteroid and break its fall if it wasn't deflected.

 

A Mercator Projection allows you to plot straight line trajectories (especially of this type of event) without worrying about the earths curvature.

 

http://en.wikipedia.org/wiki/Mercator_projection

[Harry Costas]

Hello All

 

In most cases you can work out how they are formed.

 

By either by external or by internal earth activity.

 

The moon is a different case. Most craters there are formed from meteors.

[Eclogite]

This is somewhat off-topic, and completely invalid in statistical terms, but the only time I've felt completely safe from accidentally being struck by a small (or large) meteor, is while standing in Meteor Crater, Arizona. I mean, what are the chances of a second strike in the same place within a mere 50,000 years.;)

[Turtle]

This is somewhat off-topic, and completely invalid in statistical terms, but the only time I've felt completely safe from accidentally being struck by a small (or large) meteor, is while standing in Meteor Crater, Arizona. I mean, what are the chances of a second strike in the same place within a mere 50,000 years.:singer:

 

Somewhat on topic of the off topic, you can also find sanctuary of the same statistically invalid kind in an outhouse in Norway.

[Qfwfq]

I mean, what are the chances of a second strike in the same place within a mere 50,000 years.;)

Exactly the same as the chances for it striking elsewhere. It's a Poisson distribution.

[LaurieAG]

In most cases you can work out how they are formed.

 

By either by external or by internal earth activity.

 

The moon is a different case. Most craters there are formed from meteors.

 

Hello Harry,

 

I have just read up on the 2029 passby of Apophis and it appears that it will cross over the earths orbit in the same direction of rotation. The article also showed the predicted trajectory if it did have an encounter with our planet.

 

Also, if we ever had a repeat 'visit' and there were humans around to observe and record the 'visit' in the past (like Halleys comet) there may be some manmade (or natural) structures around that follow its trajectory.