Econstudentlog

Geomorphological Landscapes of the World

I finished the book today – I liked it and gave it 3 stars on goodreads.

The Earth has a lot of interesting and beautiful places. Having a closer look at some of these wonderful places and trying to understand in some detail how those places came to be, how they formed and evolved, what they’re made of, etc. is what this book is all about. From the Mackenzie Delta in Canada over various awesome parts of the US, on to the Cockpit Country of Jamaica and the Southern Patagonian Andes to the McMurdo Dry Valleys of Antarctica, crossing Africa while talking about among other things the Namib Sand Sea, Spitzkoppe and the Afar triangle (considering the fact that you have lava lakes(!) here and that this area in general is just crazy – it includes a rift valley half-filled with volcanos… there’s incredibly little material about this place on e.g. wikipedia), having a look at Europe (the Dolomites, Dorset (this article is better than most of the above, I’d say from a brief skim), the Norwegian Fjords, amongst others things), moving on to Asia (Western Ghats, Pokhara Valley, some talk about Fenglin karst, Mt. Fuji, Mulu – among other things) and to Australia (Uluru, Bungle Bungle) and New Zealand. The book was written in order to help you to understand which physical processes have caused beautiful places all over the world to look the way they do today. I think such knowledge makes the beauty of all these places easier to appreciate – it always adds, I don’t understand how it subtracts. As for some of the places it seems obvious to me that you can only truly appreciate the beauty of those places if you also understand some of the underlying processes. It’s a bit like comparing the looks of a potential partner about whom you know nothing with the looks of the same potential partner after he or she has just told you his/her deeply fascinating life story (at least I think this is a good analogy; I’m not sure as I don’t have a lot of experience with these sorts of things).

There’s a snag, though. The book will certainly help you understand some of these things better if you’ve read a geology textbook or two before you start out – a book like this one. I should point out that one textbook may not be enough – despite having read Press and Siever I was often struggling to make sense of the material, having to look up stuff frequently, but that may be related to the fact that I read that book a while ago and so have forgotten a lot of stuff in the meantime. However if you have no background at all in physical geography and haven’t read anything about this kind of stuff, you’ll get very little out of this book. You’ll probably have a ‘…yes, I understand a few of those words…’-experience instead (and oftentimes the words you’ll understand will not help you understand what the authors are trying to tell you…). Of course you can read the words and look up all the ones you don’t understand, but most normal people are not going to read 350 pages that way if there are a lot of words in the second category. And although there are some (sometimes amazing, breathtaking..!) pictures in there, that’s probably not going to be enough…

“In basic terms, the geology at the western part of the entrance of the Guanabara Bay, including the Sugar Loaf and its vicinity, is represented by Meso- Neoproterozoic high grade metasedimentary rocks intruded by Neoproterozoic syn- to post-tectonic granitoid rocks and thin Cretaceous diabase dikes (Silva and Ramos 2002; Valeriano et al. 2003).”

In basic terms indeed – it would be interesting to see their contributions to a simple-wikipedia article. To be fair, you can say quite a bit more than that and they spend some pages talking about these things. Here’s the abstract to a chapter (all chapters have abstracts in the beginning, like all Springer publications) from the middle of the book, chapter 18 (I picked this abstract because it was in the middle of the book – there are 37 chapters altogether; I don’t think it’s a ‘special’ abstract as such):

“The landform history of the sandstone scarpland, inselberg and plains landscape of the greater Djado region, part of the presently hyper-arid central Sahara, in north-eastern Niger, begins with all-encompassing Paleogene etchplanation under humid-tropical conditions, followed by the almost compete stripping of the original soil cover and silcrete induration of the uniform etchplain during the Oligocene. Still under very humid conditions, deep-reaching karstification then penetrates silcrete, contemporaneous ferricrete and, above all, the saprolitic sandstones, also creating numerous poljes. Gradually decreasing humidity up to the end of the Neogene, resulting in increasingly restricted etchplanation, leads to the formation of scarplands, inselbergs, intra-plateau basins, pediments, and still sandstone-karstrelated scarpfoot depressions. During a final relapse to quite humid conditions, landslide fringes form along all heterolithic escarpments at the onset of the Pleistocene, later on merely subject to fluvial dissection in the context of at least three phases of Quaternary pluvial river aggradation and terrace formation. A thorough reshaping of most of the region under Quaterary arid conditions is effected by more than one phase of aeolian corrasion, as part of the largest wind-corrasion landscape on Earth.”

It makes more sense in context (well, maybe it makes perfect sense to you already – if so you’ll probably have no problems with the book), but I have actually punished the authors for the technical nature of the publication this time; if you’re a geologist this book is probably a four or five star publication, but some of these guys have made the book really hard to read for people outside the field, and this is part of the reason why I only gave it three stars. It’s a bit too much trouble to read and understand the book, and that’s a damn shame because it’s interesting stuff they cover. Having said this I should add though that I’ll probably try to remember in the future that I have this book, in case I suddenly become very rich and feel a great desire to travel the world. You’ll want to know stuff like the stuff in this book if you’re ever going to visit those places – if you don’t know this kind of stuff your experience will be partly spoiled (compared to the alternative) on account of your ignorance. And there’s a lot of stuff in this book you’ll not be able to find covered online unless you really know where to look, and are willing to spend some time looking.

The book will tell you about how some waterfalls have ‘travelled’/retreated many kilometres over time because steep slopes and huge amounts of water lead to powerful erosive forces impacting the edges of the waterfalls in particular. It’ll also tell you about how some prominent features in various landscapes are really only prominent because they‘re all that’s left standing – everything else has been eroded away over millions of years. Mountains don’t always rise from the ground in the way that we usually conceptualize it – see also these images (no good wiki article about these, unfortunately). Most people probably think of cinder cone volcanos as majestic structures which have been around for a very long time. Some of them are a bit like this, but even if they are they probably have a complicated history; lava used to come out other places than you’d think, maybe the volcano has migrated over time. They sometimes do this. But then there are other kinds of volcanos. A couple of years before my father was born Parícutin was an unexceptional bit of dirt and ground on a Mexican cornfield. Then something interesting happened. A fissure formed in the ground on the 20th of February 1943 – within the first day the cone that popped up shortly after had grown to a height of 6 metres. On the 23rd of February it was 60 metres high. Half a year later, in October, the cone had reached a height of 300 metres (I should note that the numbers in the wikipedia article are somewhat different, but different numbers are provided by different sources and although the numbers differ a bit they tell a rather similar story – this volcano became very big very fast, and it basically grew out of nothing). Lava flows started running on the 23rd of February, and these ended up covering approximately 25 km2 of the surrounding areas, impacting five nearby villages (as the book notes, other effects had much wider consequences: “Ash-fall impact was much higher: the 1 m isopach covered an area of 61 km2, while the 25 cm isopach had an envelope of 233 km2, and the 1 mm isopach up to 60,000 km2.”). The volcano is no longer active – it was ‘only’ active for roughly 10 years. Nobody died. People living on Iceland were not so lucky when their island was hit by a major eruption roughly 200 years ago; that eruption killed roughly one in five people living on the island.

But talking about these things is perhaps problematic in that a big point is easy to miss; the history of the Earth is long. It’s incredibly long. This book deals with a smallish volcano showing up almost out of thin air within the lifetime of some of the readers, because that’s actually pretty amazing. But there are lots of different types of ‘amazing’ out there. A lot of interesting places have taken a long time to get to where they are now. Geological processes have been going on for a long time. A really long time. Things used to look very different, in ways which are hard to even imagine now. Continents used to be located in very different places from the places they’re located today, and the reasons why they no longer are located where they used to be located may sometimes explain why they look the way they do. Some places which are parts of various continents now used to be at the bottom of the ocean, and this includes some pretty prominent mountain ranges. It’s not perfectly clear in detail when ice became a really big deal in Antarctica, but it’s safe to say that until roughly 35 million years ago it certainly wasn’t anything much to write home about, and that near-complete ice cover didn’t happen until much later. One should also not forget that both Europeans and Americans actually had plenty of the stuff just a few tens of thousands of years ago – remember those Norvegian Fjord’s we were talking about?

The world is an interesting place, and learning more about it usually makes it more interesting. Although many of the things covered in the book are not well covered on wikipedia, I thought I should at least add some links to relevant articles covering related stuff (I bookmarked some of the articles I looked up while reading the book in order to make it easier to cover on the blog; I was questioning quite early on whether it would make sense to quote extensively from the book here), so I’ve done this below:

Karst.
Gran Sabana.
Barchan.
Saltation.
Variscan orogeny.
Coral reef.
Sill.
Diabase.
Doline.
Vadose zone.
Speleology.
Solifluction.
Peneplain.
Mass wasting.
Rock glacier.

I probably haven’t covered this book in the amount of detail it deserves. It’s a good book – and some chapters were really fascinating – it’s just a bit hard to read. If I don’t get a lot of reading done within the next days I may decide to add some more detailed coverage of this book here on the blog.

February 12, 2014 - Posted by | books, Geology

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