Interesting question, and the answer will strongly depend on what you call an "abstract landscape". Do you mean abandoning the classic foreground-middleground-background sort of composition, with a visible horizon and some sky, in favor of more graphical compositions having a stronger focus on structures and details?
My impression is that recently (means: during the past decades) there is a clear trend in serious landscape photography exactly in this direction, so many if not all of those I would rate today´s top notch landscape photographers are doing exactly what I would call "abstract landscapes". Although one would have to admit that this style goes back at least to Ansel Adams, who (besides his classically composed shots) created quite a number of such abstract images. In fact, this does not come as a surprise because, by its very nature, black-and-white photography perfectly lends itself for an abstract way of seeing (actually, when you buy a roll of b/w film, you already have paid for abstract results).
Examples? You might like:
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Michael Kenna (b/w)
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Eliot Porter (whom you might call the granddaddy of color landscape photography)
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Christopher Burkett (color)
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Charles Cramer (color)
And in case you´re prepared and don´t mind some shameless self-promotion here, you might also want to have a look at
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Frank Sirona (color)
which is me, so of course I can´t claim that the latter is doing *amazing* landscapes, which is what you were asking for. But what I can claim is that I´m doing landscapes, and that the idea of abstraction plays an important role for me.
Finally, in addition to the highly valued David Ward who was already mentioned by another poster, his british friend and colleague Joe Cornish does a lot of - now again amazing - abstract landscapes. Unfortunately, the current version of Joe´s website does not do justice to the quality of his work. But there is a book I can recommend without restrictions: Joe´s "
First Light", full of absolutely outstanding landscape photographs, together with the author´s thoughts that are highly worth reading.