Possilbity of past life on Mars?

ChristianForCats said:

I don't recall saying Earth never had a continental drift before the creation of Pangea. However, it is clear in Genesis 1 God gathered the waters together to create one huge ocean. So at some point the Earth had multiple continents prior to Pangea; then they combined to become one except for most of Antartica.

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As I understand it, Pangea is just one of the most recent supercontinent formations; it's apparently a cyclical process. Where in Genesis does it say which supercontinent was involved?

ChristianForCats said:

One question that is still far from being answered is how Mars lost most of its athmosphere.

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NASA observations from the Maven probe suggest most of it was stripped by the solar wind. Mars' magnetosphere is too weak to protect it.

ChristianForCats said:

I don't recall saying Earth never had a continental drift before the creation of Pangea. However, it is clear in Genesis 1 God gathered the waters together to create one huge ocean. So at some point the Earth had multiple continents prior to Pangea; then they combined to become one except for most of Antartica.

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Wasn't saying you did, I just thought it was worth pointing out for the sake of information.

I don't think bringing Genesis 1 into this is particularly helpful. In the first creation account the bringing together of the waters is to separate the waters of the sea from the dry land. This occurs within the larger, poetic framework of the creation week. With the first three days consisting of separation and providing space, and the second three days consisting of filling those spaces with creatures. Hence the parallels between days 1 and 4, 2 and 5, and 3 and 6. The separation of dry land and sea in day three is complimented by the filling of the dry land with terrestrial creatures, even as the separation of the waters above and the waters below on day two is complimented by the filling the sky and seas with living things on day four.

Geologically the earth has undergone tectonic shifts resulting in the formation and breaking up of supercontinents several times. Pangea being the most recent.

-CryptoLutheran

ChristianForCats said:

"God called the dry land Earth, and the gathering of the waters He called seas." So the waters must be previously apart, then later mostly combined to form the Triasstic Ocean. The plural does not make this a false statement because there werre a a couple seas during the Permian period (300 million years ago).

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I'm not saying it's a false statement, I'm asking how you know which of the several different formations of supercontinents/global oceans it refers to.

ViaCrucis said:

Just to make sure it's clear, the earth has always had continental drift. Since the earth has a molten mantle then the plates, comprising the crust, are in constant motion. Moving apart, moving into, subducting, etc. This has been going on since the cooling of the crust during the Hadean eon.

-CryptoLutheran

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Several points here are incorrect.
1. The Earth's mantle is not molten. In the very uppermost mantle, roughly the top 400km, a portion of the mantle - in some locations - is partially molten. This percentage, in the effected areas, rarely exceeds 10%.
2. The early Earth almost certainly experienced stagnant lid tectonics (i.e. no moving plates). Active plate tectonics, as presently experienced was not initiated till later. This is still an active area of research and of heated debate.
3. The plates are not, as you suggest, composed of the crust, but of the crust and the asthenosphere - the upper part of the mantle I referred to earlier.
2. This is why the term continental drift is rarely used today, since it gives an inaccurate impression of what is involved.

ChristianForCats said:

Because nobody talks about the formation of Pangea - only its separation is discussed - questions are still unanswered about how waters were gathered. What does that mean? Will we ever know what Earth could have looked like geologically before Pangea existed? I would be interested if anyone finds out.

One thing we do know for sure is if any planet was like Earth, it is Mars.

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-CryptoLutheran

ChristianForCats said:

Because nobody talks about the formation of Pangea - only its separation is discussed - questions are still unanswered about how waters were gathered. What does that mean? Will we ever know what Earth could have looked like geologically before Pangea existed? I would be interested if anyone finds out.

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On the contrary, geologists talk about the formation of Pangea and the other supercontinents, and plate tectonics is the proposed mechanism.

ChristianForCats said:

I was not trying to imply Pangea was the first. It is just the only one I learned about.

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Again, that wasn't what I was saying.

ChristianForCats said:

Ophiolite, everyone uses the term continental drift when they talk about the Atlantic Ocean growing while the Pacific Ocean shrinks.

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Not if they have received sound training in geology. I readily accept corrections from those trained in physics, genetics, avionics and a bunch of other subjects of which I lack detailed knowledge. I think it makes sense to adopt the correct terminology when one becomes aware of it.
{Emphasis added}

ChristianForCats said:

Where this goes wrong is the drift could not begin before Pangea separated.

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The movement of plates was ongoing before Pangea separated, so your statement is incorrect. (Unless you wish to invent a new and meaningless/misleading definition for continental drift.)

ChristianForCats said:

So if you are talking about how it started, the correct term is earthquake (at least where what we always call South America broke off from Africa).

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Incorrect. An earthquake is a specific energy release occasioned by movement along a fault plane (or more usually along a series of fault planes and zones). Such movement is an essential part of plate tectonics. If you wish to identify "how it started" you need to look to convective motion in the solid mantle.

ChristianForCats said:

But after that happened and South America turned itself around it's accurate to call the plate tectonic movement a continental drift.

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1. South America did not "turn itself around".

2. The term continental drift is misleading and has been progressively abandoned by the geological community. The term plate tectonics was first used in print in a 1969 paper in Nature. (McKenzie, D.P. & Morgan, W.J. (1969). Evolution of triple junctions. Nature 224, 125–33). Even before then reference was being made to sea floor spreading was posited by Hess and expanded upon by Dietz, and demonstrated through the analysis of magnetic anomalies, first by Mason, then by Vine and Mathews.(See - Hess, H.H. (1962). History of Ocean Basins. In Petrologic Studies –A Volume in Honor of A.F. Buddington, pp.599–620; Dietz, R.S. (1961). Continent and ocean basin evolution by spreading of the sea floor. Nature 190, 854–7; Mason,R.G.(1958).A magnetic survey of the west coast of the United States between latitudes 32◦and36◦N, longitudes 121◦ and 128◦ W. Geophys.J.Roy.Astron.Soc.1,320–9; Vine, F.J. & Matthews, D.H. (1963). Magnetic anomalies over oceanic ridges. Nature 199, 947–9)
Thereafter the term was progressively dropped, except when referring to the historical development of both theories.

3. Continental drift envisaged sialic continents drifts over simatic oceans. That does not occur. Plates, that may be continental, oceanic, or a combination, move over the relatively weak asthenosphere. The two processes are quite different, though they share come common features. Calling plate tectonics continental drift it not too much different to calling the Big Bang Theory, Steady State Theory.

ChristianForCats said:

How did it rotate from a NW-SE angle to its current N-S direction?

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In my understanding of language "turn itself around" refers to a rotation of approximately 180 degrees. Given what you actually meant, here is the answer: that was due to a relative rotation of the plate that includes the continental mass of South America. Do you understand that is an important distinction? The South American continent did not rotate in isolation, but rotated with the attached western South Atlantic oceanic plate and the Nazca plate in the Pacific.

ChristianForCats said:

So continents just broke apart without the kind of movement that causes earthquakes?

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Earthquakes occurred, but the earthquakes are a consequence of forces generated between plates by three other factors:

• Slab pull, where a subducting slab drags the plate towards the the subduction zone
• Ridge push, where the cool lithosphere slides down the expanded, warm asthenosphere beneath the mid-ocean ridge
• Convection currents in the mantle

The relative importance of each is still a subject of some debate, but I think the current consensus favours slab pull as being the most important.

ChristianForCats said:

Yes I know that was not exactly the right phrase, but could not think of a better way to put it.

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I understand. I'm not nitpicking, just seeking to educate in a field I have some grounding in.

*** Can anyone spot the three unconscious puns? I could only find two!