Normally I pass on responding to stuff like this. But I felt like this one was important enough to address before I jumped into my other topic.
Three points here:
- Claims of quote-mining and dishonesty
- My original intent
- The supposed Answer.
1. Claims of quote-mining and dishonesty
Roy, do you really think I was hoping to fool people in this forum through some form of quote mining? I know how smart, and thorough people are here. I knew full well that people would read the article and read about the answer given. (Also note that I did include the phrase “have answered” in my quotation there, just didn’t put it in bold. See why below).
In fact, while I was writing up my post, I actually started talking about their ‘answer’, because there were a few things I wanted to point out about it. However it was getting late that evening, and I just didn’t have that paragraph polished enough (for this group of reviewers), so at the last moment I just deleted it, sent my post, and knew full well that someone would bring up the proposed answer in that paper, and give me more time to think about my response. It also would have given me a chance to hear what others said about “the answer” before I put in my take. What I didn’t anticipate was that the removal of that un-polished paragraph would have given you the opportunity to post a critical response hinting at me being a “lying charlatan”.
Listen, I’m not a very experience forum-poster. I’ve realized that. But I’m learning. You and others being critical of me are only helping refine me at forum-posting. Lesson learned. I’ll make sure not to give you that opportunity again.
2. My original intent
Hear me on this one regarding my original post. I wasn’t just trying to take some cheap-shots by throwing out “long-standing mystery” quotes. For me the issue was how easily I see dismissive “no mystery or surprise” or other no-problem-here kind of comments made in this forum. What I’m real curious about is this: Prior to this studying being done and an apparent “answer” being proposed, if someone would have mentioned a “long-standing mystery” about the Great Escarpment” would it have been met with honesty, or simply dismissal as a challenge? Those who’ve been here for some time might know the answer to that.
3. The supposed Answer.
So Ron and Tim, you feel confident in your declaration of this problem as “answered”.
Is it really proper to declare it “answered”? After reading through that, and other articles (and the original study) a bit, I feel like that’s more a matter of opinion.
I’ve read through that article, and see things like this:
Meanwhile, the rifting event also sets about a “deep mantle wave” that travels along the continent’s base at about 15–20 kilometers per million years.
They believe that this wave convectively removes layers of rock from the continental roots.
A few questions arise for me:
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This is a narrative based on a computer simulation. How confident can we be that there really are “deep mantle waves” traveling at 15-20 km per million years? That seems like a difficult thing to confirm.
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It says that “They believe” the waves remove layers of rock from the bottom of the continent. How confident are we that they really are removing rock? Saying “They believe” doesn’t sound like confirmation enough to call this “answered”. To me, it sounds more properly like a narrative that is being refined as a proposed solution. But if my assessment is wrong, I’m open to seeing why.
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At that very slow rate, the very large uplifted area would have not been lifted all at the same time, but very slowly (at a pace of roughly 15-20 km per million years). As soon as an area is uplifted, it is subjected to increased erosion. Wouldn’t we see varied amounts of erosion and undulation across the land in the direction of movement of the wave?
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The South African great escarpment has some step edges to it. A good example is the Drakensberg Escarpment area. See here. According to this model, how long ago were those cliffs created? Because they look relatively young. I would have expected them to be rounded off more.
And from another article here (discussing the same study): We discovered a new way mountains are formed – from ‘mantle waves’ inside the Earth.
if these mantle waves strip some 30 to 40 kilometres of rocks from the roots of continents, as we propose they should, it will have a cascade of major impacts at the surface.
Could our mantle wave offer a fresh explanation?
[emphasis mine]
“if” and “Could” don’t sound like the right words to use if we’re calling this problem “answered”
I tried reading through the original paper published here: Coevolution of craton margins and interiors during continental break-up | Nature. I’ll admit, it was rather technical. But I did scan parts of it.
I’m open to anyone giving me confident answers to my questions. But in the meantime, I still have those questions above.
But let me stop here. When I read this article, I just don’t see how one can be confident enough to call this “the answer”. Given that, Ron, you are implying that I personally needed to make sure to declare that this problem “has been answered” to everyone. I just can’t do that. All I can say is that scientists are working on a narrative to address the problem. And I know everyone can read that article for themselves, and come to their own conclusion.
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