Chapter 51. Does the Weathering Hypothesis Explain Planation
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Chapter 40. Appalachian Planation Surfaces
Chapter 40 Appalachian Planation Surfaces The Appalachian region not only includes the mountains, but also the surrounding provinces. During the erosion episode (see Chapter 8 and Appendix 4), rocks of the Appalachians were sometimes planed into a flat or nearly flat planation surface, especially on the provinces east and west of the Blue Ridge Mountains (Figure 40.1). But planation surfaces are also found in the Appalachian Mountains, mainly on the mountaintops. Figure 40.1. Map of the Appalachian provinces and the two provinces to the west (from Aadland et al., 1992). Due to their rolling and dissected morphology, the Appalachian provinces are rarely called planation surfaces, but they would mostly be erosion surfaces. I will continue to use the more descriptive term, planation surface, with the understanding that many of these are erosion surfaces. The Appalachian provinces exhibit three possible planation surfaces, from east to west, they include: (1) the Piedmont Province, (2) the accordant mountaintops of the Valley and Ridge Province (part of the Appalachian Mountains), and (3) the Appalachian Plateau which is divided into the Allegheny Plateau in the north and the Cumberland Plateau in the south. I also will include the Interior Low Plateaus Province to the west of the Appalachian Plateau. Many articles have been published about the Appalachian planation surface. Their origin is controversial among secular geologists, but they can readily be explained by the runoff of the global Genesis Flood. Figure 40.2. Lake on the Piedmont near Parkersville, South Carolina, showing general flatness of the terrain. The Piedmont Planation Surface The Piedmont Province begins just east of the Blue Ridge Mountains from the Hudson River in the north to Alabama in the south. -
The Remarkable African Planation Surface Michael J
Papers The remarkable African Planation Surface Michael J. Oard Geomorphology, within the uniformitarian paradigm, has great difficulty explaining the origin of landforms. One of these landforms, most of which were once much larger, is the planation surface. Planation surfaces are common and worldwide. They are not forming today but are being destroyed. Africa is covered with the most planation surfaces of any continent, but the number and age of the planation surfaces has always been controversial. A new synthesis of African planation surfaces concludes that there is one large, warped planation surface on Africa, called the African Surface. Most of the African Surface is capped by a chemical precipitate called a duricrust, the origin of which is a puzzle. Planation and erosion surfaces could readily have formed as the floodwater retreated off the continents during uplift. eologists once thought that by throwing out the Genesis minor forms such as hill, valley, slope, esker, and GFlood in Earth history they could easily explain the dune.”5 features of the earth’s surface. William Morris Davis, the Other names for geomorphology are ‘physiography’ most renowned geomorphologist in the early and mid- and ‘physical geography’. Various regions of the earth have twentieth century, stated: been subdivided according to similar geomorphology and “The emancipation of geology from the doctrine are called ‘provinces’. of catastrophism was a necessary step before The definition of ‘landform’ from the fifth edition of the progress could be made towards an understanding Glossary of Geology is the same as the one from the older of the lands.”1 Dictionary of Geological Terms,6 except for the addition As a result of this shift in worldview in the of the phrase “by natural processes”. -
Formation Mechanism for Upland Low-Relief Surface Landscapes in the Three Gorges Region, China
remote sensing Article Formation Mechanism for Upland Low-Relief Surface Landscapes in the Three Gorges Region, China Lingyun Lv 1,2, Lunche Wang 1,2,* , Chang’an Li 1,2, Hui Li 1,2 , Xinsheng Wang 3 and Shaoqiang Wang 1,2,4 1 Key Laboratory of Regional Ecology and Environmental Change, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China; [email protected] (L.L.); [email protected] (C.L.); [email protected] (H.L.); [email protected] (S.W.) 2 Hubei Key Laboratory of Critical Zone Evolution, School of Geography and Information Engineering, China University of Geosciences, Wuhan 430074, China 3 Hubei Key Laboratory of Regional Development and Environmental Response, Hubei University, Wuhan 430062, China; [email protected] 4 Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China * Correspondence: [email protected] Received: 9 November 2020; Accepted: 26 November 2020; Published: 27 November 2020 Abstract: Extensive areas with low-relief surfaces that are almost flat surfaces high in the mountain ranges constitute the dominant geomorphic feature of the Three Gorges area. However, their origin remains a matter of debate, and has been interpreted previously as the result of fluvial erosion after peneplain uplift. Here, a new formation mechanism for these low-relief surface landscapes has been proposed, based on the analyses of low-relief surface distribution, swath profiles, χ mapping, river capture landform characteristics, and a numerical analytical model. The results showed that the low-relief surfaces in the Three Gorges area could be divided into higher elevation and lower elevation surfaces, distributed mainly in the highlands between the Yangtze River and Qingjiang River. -
Chapter 41. Canadian Planation Surfaces
Chapter 41 Canadian Planation Surfaces Chapters 36 to 40 summarized information on planation surfaces in the United States, but also included several planation surfaces on the High Plains of south-central Canada. There are numerous planation surfaces in the rest of Canada that are important for understanding the continent wide nature of Flood runoff. Figure 41.1 is a map of the geomorphological regions of Canada, many of which I will be mentioning in this chapter. Since Alaskan geomorphology is generally an extension of northwest Canadian geomorphology, Alaska will be included in this chapter on Canadian planation surfaces. Figure 41.1. The general geomorphological regions of Canada (from Bostock, 1970, p. 12). The Huge Canadian Shield Exhumed Planation Surface The Canadian Shield, west, south, and east of Hudson Bay (Figure 41.1) is a huge dissected planation surface.1,2 However, it is and exhumed planation surface (see Appendix 15). The surface was first planed, covered by sediments that hardened into rock, and then re-eroded 1 Bostock, H.S., 1970. Physiographic subdivisions of Canada. In, Douglas, R.J.W. (editor), Geology and Economic Minerals of Canada, Part A, Geological Survey of Canada, Economic Geology Report 1, Ottawa, Canada, pp. 9–30. 2 Ambrose, J.W., 1964. Exhumed paleoplains of the Precambrian Shield of North America. American Journal of Science 262:817–857. exposing most of the surface. The planation surface on the southeast part of the shield has been documented by Ian Juby,3 summarized in Appendix 18. The evidence for the Canadian Shield being a planation surface is that the surface continues underneath the sedimentary rocks that still remain on parts of the exhumed surface.4 It is also interesting that glaciation only superficially modified the planation surface,4 which is strange if there were 30 or more ice ages during the past 2.5 million years,5 as purported by uniformitarian scientists. -
Etchplain, Rock Pediments, Glacises and Morphostructural Analysis of the Bohemian Massif (Czech Republic) Jaromir Demek [email protected] Rudka Č
GeoMorfostrukturnímorfologický a sborník tektonické 2 problémy ČAG, ZČU v Plzni, 2003 Etchplain, rock pediments, glacises and morphostructural analysis of the Bohemian Massif (Czech Republic) Jaromir Demek [email protected] Rudka č. 66, Kunštát na Moravě CZ 679 72 The Bohemian Massif forms the western part of Czech Republic. The massif belongs to the Western European Platform, which basement was consolidated by Variscan folding. The Bohemian Massif is characterized by a typical platform regime during Mesozoic and Paleogene Periods, i.e. by low intensity of tectonic movements and slight relief differentiation. This regime was reflected in a structural compatibility and morphological uniformity of the Massif, with altitudes of its planated surface (mostly peneplain with thick regolith mantle) ranging from 0 to 200 m a.s.l. The present-day relief of the Bohemian Massif developed for the most part in the Neotectonic period (Upper Oligocene to Quaternary). The older idea that o the Bohemian Massif responded to stresses caused by neotectonic movements generally as a rigid unit (with some differences in individual regions) and o that in the Bohemian Massif preserved in very large extent old peneplain (KUNSKÝ, 1968, p. 27), seams to be abandoned now. Already in 1930 Ms. Julie Moschelesová proposed the hypothesis of neotectonic megaanticlinals and megasynclinals in the basement of the Bohemian Massif. At present the Bohemian Massif is understood as a complex mountain, which relief is composed of megaanticlinals and megasynclinals, horstes and grabens and volcanic mountains? Individual parts of the Bohemian Massif moved in different directions and with different intensity during Neotectonic Period. The determination of directions, intensity and type of Neotectonic deformations of the Earth’s crust is difficult due to lack of correlated deposits. -
Cainozoic Evolution of Lower Silesia, Sw Poland: a New Interpretation in the Light of Sub-Cainozoic and Sub-Quaternary Topography
Acta Geodyn. Geomater.Vol.1, No.3 (135), 7-29, 2004 CAINOZOIC EVOLUTION OF LOWER SILESIA, SW POLAND: A NEW INTERPRETATION IN THE LIGHT OF SUB-CAINOZOIC AND SUB-QUATERNARY TOPOGRAPHY Janusz BADURA 1) *, Bogusław PRZYBYLSKI 1) and Witold ZUCHIEWICZ 2) 1) Lower Silesian Branch, Polish Geological Institute, al. Jaworowa 19, 50-122 Wrocław, Poland 2) Institute of Geological Sciences, Jagiellonian University, ul. Oleandry 2A, 30-063 Kraków, Poland *Corresponding author‘s e-mail: [email protected] (Received March 2004, accepted June 2004) ABSTRACT An analysis of the youngest tectonic movements by the use of either morphometric or instrumental techniques should take into account both exposed and buried fault zones. The sub-Cainozoic and sub-Quaternary surface maps presented in this study display buried palaeotopography whose interpretation proves helpful in identification of tectonic dislocations. Such a kind of analysis has been conducted for the area of Lower Silesia, including the Sudetes, Fore-Sudetic Block, and Fore-Sudetic Monocline. The maps have been constructed on the basis of well-bore data, vertical geoelectrical soundings, and detailed mapping of exposures of pre-Quaternary rocks. Well-bore data have been reinterpreted with a view to reconstruct the original depth to the top of the crystalline basement. Many archival borehole descriptions place the boundary between Tertiary strata and the Proterozoic-Palaeozoic substratum at the top of poorly weathered rocks, including regoliths of the crystalline substratum into the Tertiary cover. The presented maps portray for the first time the actual morphology of the sub-Cainozoic surface. A comparison between the sub-Cainozoic and sub-Quaternary surface maps enables us to document changes in tectonic mobility throughout Cainozoic times. -
GEOGRAPHICAL ASSOCIATION of ZIMBABWE
GEOGRAPHICAL ASSOCIATION of ZIMBABWE GEOGRAPHICAL JOURNAL OF ZIMBABWE N u m b e r 20 D ecem b er, 1989 page T r a n s p o r t a n d m a r k e t in g o f horticultural C r o ps b y C o m m u n a l f a r m e r s in t o H a r a r e JA . Smith 1 St r a t e g ie s f o r Co p in g w it h f o o d D e f ic it s in r u r a l Z im b a b w e d j . Campbell, 15 LM.ZinyamaandT.Matiza An a l y s is o f An n u a l r a in f a l l in Z im b a b w e f o r t r e n d s a n d P eriodicities , 1891-1988 D. Mazvimavi 42 TOURISM TO PARKS in ZIMBABWE: 1969-1988 G. Child, R. Heath and A. Moore 53 L a n d s c a p e E v o l u t io n in So u t h e r n AFRICA AND ZIMBABWE: T r a d it io n a l a n d r e c e n t v ie w s R. Whitlow 79 instructions t o Au t h o r s 105 ISSN 1011-5919 Distributed free to all members Price $6.00 © Geographical Association of Zimbabwe, 1989 Published by Geographical Association of Zimbabwe? c/o Geography Department University of Zimbabwe P.O. -
Long-Term Landscape Evolution, Genesis, Distribution and Age
GONDWANA PALEOLANDSCAPES: LONG-TERM LANDSCAPE EVOLUTION, GENESIS, DISTRIBUTION AND AGE Jorge RABASSA 1,2 (1) Laboratorio de Cuaternario y Geomorfología, CADIC-CONICET, Bernardo Houssay 200, 9410. Tierra del Fuego, Argentina. E-mail: [email protected] (2) Universidad Nacional de la Patagonia - San Juan Bosco, Sede Ushuaia. “Let the landscape teach me” Lester C. King, personal letter to Charles Higgins, 1958. “While the geologist may often be in error, the Earth is never wrong” Lester C. King, 1967. Introduction The Concepts of Gondwana Paleolandscapes and Long-Term Landscape Evolution: Previous Works Gondwana Paleolandscapes: Basic Scientific Concepts Related The Evolution of the Gondwana Cratonic Areas During the Mesozoic Mesozoic and Paleogene Climates Granite Deep Weathering Passive-Margin Geomorphology Duricrusts: Ferricretes, Silcretes, Calcretes A Brief and Preliminary Review of Gondwana Landscapes and Other Ancient Paleolandscapes in the Southern Hemisphere and Other Parts of the World Discussion and Conclusions Acknowledgements Bibliographic References ABSTRACT – The concept of “Gondwana Landscape” was defined by Fairbridge (1968) as an “ancestral landscape” composed of “series of once-planed remnants” that “record traces of older planation” episodes, during the “late Mesozoic (locally Jurassic or Cretaceous)”. This has been called the “Gondwana cyclic land surface” in the continents of the southern hemisphere, occurring extensively in Australia, Southern Africa and the cratonic areas of South America. Remnants of these surfaces are found also in India, in the northern hemisphere and it is assumed they have been preserved in Eastern Antarctica, underneath the Antarctic ice sheet which covers that region with an average thickness of 3,000 meters. These paleolandscapes were generated when the former Gondwana super-continent was still in place and similar tectonic conditions in its drifted fragments have allowed their preservation. -
The Puzzle of Planation Surfaces
PART VII The Puzzle of Planation Surfaces During the Retreating Stage of the Flood, the mountains rose and the valleys (basins) sank (Psalm 104:8) and the Floodwater receded off the continents. This great tectonic movement caused the Floodwater that entirely covered the Earth at Day 150 to retreat off the soon-to-be exposed land. Great sheet erosion of the rising continent ensued during the Sheet Flow Phase of the Flood, leaving behind escarpments, tall erosional remnants, arches, large natural bridges, long-transported gravel, and other features. At the same time, this great erosion scoured the land and formed erosion and planation surface. Planation surfaces are common, yet a major mystery of uniformitarian geomorphology. This and subsequent parts will explore the subject of the ubiquitous planation surfaces on all the continents and what they means. Chapter 32 What Is a Planation Surface? According to the Glossary of Geology, an erosion surface is: "A land surface shaped and subdued by the action of erosion, esp. by running water. The term is generally applied to a level or nearly level surface"1 An erosion surface is generally synonymous with a planation surface, except that an erosion surface is generally regarded as a rolling surface of low relief. A planation surface is nearly flat. Planation and erosion surfaces can be seen in many areas of the world.2 Today, comparatively small planation surfaces (strath terraces) are formed when a river floods, overflows its banks, and planes bedrock to a horizontal or near horizontal surface.3 But, present processes do not form planation surfaces of any significant size. -
Pediments Formed by the Flood — Oard Pediments Formed by the Flood — Oard
Overviews The definition of a pediment is quite broad and has Pediments formed been subject to disagreement over terms.3,4 I will refer to pediments as planation surfaces since many pediments are quite smooth. by the Flood: Pediments are most evident in dry climates, which, as in the definition above, has led to many ascribing them evidence for the to a dry climate mechanism. However, this may only be a selection artifact in that deserts often preserve features Flood/post-Flood better and have greater rock exposure.5 Yet, pediments are not restricted to dry areas and may be observed in any climate, cold or warm, wet or dry.6 For instance, pediments boundary in the are common in the Yukon Territory of north-west Canada.7 The geomorphologist Lester King states: Late Cenozoic ‘They [pediments] are, however, not absent from the landscapes of humid regions, and current Michael J. Oard research indicates that pediments are, indeed, the most widespread and possibly the most important of all land-forms.’8 Contrary to the uniformitarian principle that ‘the The geologist Grove Karl Gilbert first recognized present is the key to the past’, pediments are not and described pediments in 1877 and there is now an ex- observed to be forming today. The three main tensive literature on the subject.6,9,10 There are hundreds of theories for the origin of pediments are fatally flawed. pediments in the south-west United States. Figure 1 is just Only Crickmay’s superflood hypothesis comes one example of a pediment along a mountain ridge, 10 km anywhere close to a solution, in that it postulates south-east of Hoover Dam, Nevada. -
Summary PHYSISCHE GEOGRAPHIE
Mitteilungen der Österreichischen Geographischen Gesellschaft, 152. Jg. (Jahresband), Wien 2010, S. 87–129 physische GeoGraphie Julius Büdel und die Klima-GeomorpholoGie1) Armin Skowronek, Bonn* mit 3 Abb. im Text Inhalt Summary ...............................................................................................................87 Zusammenfassung .................................................................................................88 0 Vorbemerkung ..................................................................................................88 1 Einleitung ........................................................................................................89 2 Die Klima-Geomorphologie Büdels .................................................................90 3 Zur Rezeption des Büdelschen Konzepts ........................................................106 4 Stellung und Bedeutung der Büdelschen Klima-Geomorphologie ...................118 5 Literaturverzeichnis .......................................................................................120 Summary Julius Büdel and Climatic Geomorpholgy The geomorphological models of peneplain and valley formation of the prominent and influential German geographer Julius Büdel (1903–1983) are taken by a critical analysis. It demonstrates that the “double planation” in the humid tropics substantiated by weathering and soil formation processes and therefore by actual climate factors and the in the same way substantiated “ice rind effect” in the subpolar regions are -
Tors in Central European Mountains – Are They Indicators of Past Environments? ISSN 2080-7686
Bulletin of Geography. Physical Geography Series, No. 16 (2019): 67–87 http://dx.doi.org/10.2478/bgeo-2019-0005 Tors in Central European Mountains – are they indicators of past environments? ISSN 2080-7686 Aleksandra Michniewicz University of Wroclaw, Poland Correspondence: University of Wroclaw, Poland. E-mail: [email protected] https://orcid.org/0000-0002-8477-2889 Abstract. Tors represent one of the most characteristic landforms in the uplands and mountains of Central Europe, including the Sudetes, Czech-Moravian Highlands, Šumava/Bayerischer Wald, Fichtel- gebirge or Harz. These features occur in a range of lithologies, although granites and gneisses are particularly prone to tor formation. Various models of tor formation and development have been pre- sented, and for each model the tors were thought to have evolved under specific environmental con- ditions. The two most common theories emphasised their progressive emergence from pre-Quaternary weathering mantles in a two-stage scenario, and their development across slopes under periglacial conditions in a one-stage scenario. More recently, tors have been analysed in relation to ice sheet ex- tent, the selectivity of glacial erosion, and the preservation of landforms under ice. In this paper we describe tor distribution across Central Europe along with hypotheses relating to their formation and Key words: development, arguing that specific evolutionary histories are not supported by unequivocal evidence tors, and that the scenarios presented were invariably model-driven. Several examples from the Sudetes deep weathering, are presented to demonstrate that tor morphology is strongly controlled by lithology and structure. periglacial processes, The juxtaposition of tors of different types is not necessarily evidence that they differ in their mode glacial erosion, of origin or age.