scholarly journals How Climate, Uplift and Erosion Shaped the Alpine Topography

Elements ◽  
2021 ◽  
Vol 17 (1) ◽  
pp. 41-46
Author(s):  
Pierre G. Valla ◽  
Pietro Sternai ◽  
Matthew Fox

Decades of scientific research on the European Alps have helped quantify the vast array of processes that shape the Earth’s surface. Patterns in rock exhumation, surface erosion and topographic changes can be compared to sediment yields preserved in sedimentary basins or collected from modern rivers. Erosion-driven isostatic uplift explains up to ~50% of the modern geodetic rock uplift rates; the remaining uplift reveals the importance of internal processes (tectonics, deep-seated geodynamics) and external processes (glacial rebound, topographic changes). We highlight recent methodological and conceptual developments that have contributed to our present view of the European Alps, and we provide suggestions on how to fill the gaps in our understanding.

Author(s):  
Abah P. Omale ◽  
Juan M. Lorenzo ◽  
Ali AlDhamen ◽  
Peter D. Clift ◽  
A. Alexander G. Webb

Faults offsetting sedimentary strata can record changes in sedimentation driven by tectonic and climatic forcing. Fault kinematic analysis is effective at evaluating changes in sediment volumes at salt/shale-bearing passive margins where sediment loading drives faulting. We explore these processes along the northern Gulf of Mexico. Incremental throw along 146 buried faults studied across onshore Louisiana revealed continual Cenozoic fault reactivation punctuated by inactive periods along a few faults. Fault scarp heights measured from light detection and ranging (LiDAR) data are interpreted to show that Cenozoic fault reactivation continued through the Pleistocene. The areas of highest fault throw and maximum sediment deposition shifted from southwest Louisiana in the early Miocene to southeast Louisiana in the middle−late Miocene. These changes in the locus of maximum fault reactivation and sediment deposition were controlled by changing tectonics and climate in the source areas. Early Miocene fault throw estimates indicate a depocenter farther east than previously mapped and support the idea that early Miocene Appalachian Mountain uplift and erosion routed sediment to southeast Louisiana. By correlating changes in fault throw with changes in sediment deposition, we suggest that (1) fault kinematic analysis can be used to evaluate missing sediment volumes because fault offsets can be preserved despite partial erosion, (2) fault throw estimates can be used to infer changes in past tectonic and climate-related processes driving sedimentation, and (3) these observations are applicable to other passive margins with mobile substrates and faulted strata within overfilled sedimentary basins.


1978 ◽  
Vol 18 (1) ◽  
pp. 143 ◽  
Author(s):  
A.J Kantsler ◽  
G. C. Smith ◽  
A. C. Cook

Vitrinite reflectance measurements are used to determine the vertical and lateral patterns of rank variation within four Australian sedimentary basins. They are also used to estimate palaeotemperatures which, in conjunction with present well temperatures, allow an appraisal of the timing of coalification and of hydrocarbon generation and distribution.The Canning Basin has a pattern of significant pre-Jurassic coalification which was interrupted by widespread uplift and erosion in the Triassic. Mesozoic and Tertiary coalification is generally weak, resulting in a pattern of rank distribution unfavourable to oil occurrence but indicating some potential for gas. The Cooper Basin also has a depositional break in the Triassic, but the post-Triassic coalification is much more significant than in the Canning Basin. The major gas fields are in, or peripheral to, areas which underwent strong, early, telemagmatic coalification whereas the oil-prone Tirrawarra area is characterized by a marked rise in temperature in the late Tertiary. The deeper parts of the Bass Basin underwent early coalification and are in the zone of oil generation, while most of the remaining area is immature. Inshore areas of the Gippsland Basin are also characterized by early coalification. Areas which are further offshore are less affected by this phase of early maturation, but underwent rapid burial and a sharp rise in temperature in the late Tertiary.


1993 ◽  
Vol 40 (1) ◽  
pp. 70-80 ◽  
Author(s):  
Ian D. Goodwin

AbstractA Holocene deglaciation sequence for the Windmill Islands was determined from the 14C age of raised marine shorelines, lakebottom sediments, and Adelie penguin remains found in abandoned rookeries. A north-south gradient in the elevation of the upper marine limit was observed, with the highest marine limit (31-32 m) observed on Browning Peninsula and Hull Island at the southern edge of the islands. Correspondingly, the southern islands were found to have been deglaciated by 8000 (corr.) yr B.P. while the northern islands were deglaciated by 5500 (corr.) yr B.P. Isostatic uplift rates were calculated as 0.5 to 0.6 m/100 yr, with an estimated total uplift of around 53 m which indicates late Pleistocene ice sheet thicknesses of 200 and 400 m over the islands and adjacent Petersen Bank, respectively. The margin of the Late Pleistocene grounded ice sheet extended an estimated 8-15 km offshore which coincides with the location of the 200 m isobath.


2002 ◽  
Vol 173 (2) ◽  
pp. 97-112 ◽  
Author(s):  
Michel Séranne ◽  
Hubert Camus ◽  
Francis Lucazeau ◽  
Jocelyn Barbarand ◽  
Yves Quinif

Abstract The Cévennes are bordering the French Massif Central and the Gulf of Lion margin. The morphogenesis of this area results from an interaction between deep-seated and superficial processes, whose origin and timing is still discussed. We attempt a reconstruction of the surrection and erosion history of the area through a multidisciplinary approach including geology, geomorphology, thermochronology and geochronology. Thermochronology shows that the Cévennes basement underwent some 2 km denudation in mid-Cretaceous time. Analyses of the sediments preserved on uplifted surfaces and in peripheral sedimentary basins indicate a differential surface uplift of the Cevennes, of the surrounding calcareous plateaus, and of the coastal plain, that occurred in several stages during the Tertiary. Early Miocene rifting of the Gulf of Lion margin and opening of the NW Mediterranean drastically modified the drainage network. Geomorphology analyses of the incised rivers and karst network suggest that most of the incision results from uplift that occurred sometime in the Serravalian-Tortonian interval. U/Th dating of calcite concretions in karsts allows to chronologically bracket the formation of some fluvial terraces, and to find very low incision rates during the Pleistocene. Most of the morphogenesis predates the Quaternary. This ongoing study shows an example of polyphased and very slow morphogenesis, with present-day landscape including elements as old as Cretaceous.


2020 ◽  
Author(s):  
Peter Japsen ◽  
Paul F. Green ◽  
James A. Chalmers

<p>The Carboniferous to Palaeogene Wandel Sea Basin of North Greenland is an important piece in the puzzle of Arctic geology, particularly for understanding how the Paleocene–Eocene movement of the Greenland Plate relates to the compressional tectonics in the High Arctic; e.g. Eurekan Orogeny (arctic Canada), West Spitzbergen Orogeny (Svalbard) and Kronprins Christian Land Orogeny (North Greenland). We will refer collectively to these manifestations related to the movement of the Greenland Plate as the Eurekan Orogeny. Here, we present apatite fission-track analysis (AFTA) and vitrinite reflectance (VR) data combined with observations from the stratigraphic record to place constraints on the timing of key tectonic events.</p><p>Our study reveals a long history of episodic burial and exhumation since the collapse of the Palaeozoic fold belts along the east and north coasts of Greenland. Our results provide evidence for pre-Cenozoic phases of uplift and erosion in Early Permian, Late Triassic, Late Jurassic and mid-Cretaceous times, all of which involved removal of sedimentary covers that were 2 km thick or more.</p><p>Paleocene cooling and exhumation affected the major fault zones of the Wandel Sea Basin. The Paleocene episode thus defines the timing of the compressional event that caused folding and thrusting of Upper Cretaceous and older sediments along these fault zones. We conclude that the Paleocene inversion of the fault zones took place in the initial phase of the Eurekan Orogeny after the onset of seafloor spreading west of Greenland</p><p>Regional cooling, reflecting exhumation of the Wandel Sea Basin and surrounding regions, began at the end of the Eocene. Prior to the onset of exhumation, a cover of about 2.5 km of Paleocene–Eocene sediments had accumulated across a wide area. Northern Peary Land, north of the Harder Fjord Fault Zone, was uplifted about 1 km more than the area south of the fault zone during this episode. Regional denudation and reverse faulting that began at the end of the Eocene took place after the end of sea-floor spreading in the Labrador Sea and thus represent a post-Eurekan tectonic phase. A major plate reorganisation in the NE Atlantic and regional exhumation of West and East Greenland and adjacent Arctic regions took place at the same time, coinciding with a minimum of spreading rates in the NE Atlantic followed by expansion of the Iceland Plume.</p><p>Cooling from mid-late Miocene palaeotemperatures at sea level correspond to burial below a rock column about 1.8 km thick.</p><p>The preserved sedimentary sequences of the Wandel Sea Basin represent remnants of thicker strata, much of which was subsequently removed during multiple episodes of uplift and erosion. The thickness of these sedimentary covers implies that they must have extended substantially beyond the present-day outline of the basin, and thus that it at times was coherent with the sedimentary basins in the Arctic, as has been suggested from stratigraphic correlations.</p>


1971 ◽  
Vol 1 (4) ◽  
pp. 522-531 ◽  
Author(s):  
Richard H. Fillon

Postglacial uplift data from 33 sites in northeastern North America reveal that during the period from 11,000 years B.P. to 7000 years B.P., glacio-isostatic uplift rates varied in a consistent manner with distance from the former margin of the Laurentide Ice Sheet. The consistent trends of these uplift rate variations with distance from the former ice sheet margin suggest that they were not the result of changes in the rate of ice sheet retreat or local tectonic activity. They instead may have resulted from rebound affected significantly by the earth's viscosity at a depth approximately equal to the wavelength of isostatic deformation [McConnell, R.K., Jr., Journal of Geophysical Research70, 5171 (1965)]. Extremely high viscosities below 600 km, however, probably provide the lower limit for this relationship.


2017 ◽  
Vol 8 (1) ◽  
Author(s):  
Jürgen Mey ◽  
Dirk Scherler ◽  
Andrew D. Wickert ◽  
David L. Egholm ◽  
Magdala Tesauro ◽  
...  

1979 ◽  
Vol 16 (7) ◽  
pp. 1428-1438 ◽  
Author(s):  
Randall R. Parrish

The Wolverine Complex is a metamorphosed and polydeformed sequence of Hadrynian clastic rocks that forms part of the Omineca Crystalline Belt in north-central British Columbia. Twenty-six Rb–Sr and K–Ar dates from an area at the north end of the complex are presented. Rb–Sr muscovite dates are the oldest, 70–166 Ma, and constrain the main metamorphic–deformational event to the Middle to Late Jurassic or earlier. K–Ar dates on muscovite and biotite are highly discordant and the dates of the minerals vary in the order Rb–Sr muscovite > K–Ar muscovite > K–Ar biotite. Many rocks show partial or complete homogenization of the isotopes during an early Tertiary thermal event, which has extensively reset K–Ar dates in part of the complex.The blocking temperatures of the isotopic systems when combined with the isotopic dates, other published dates, and estimated geothermal gradients, allow inference of thermal history and paleo-uplift rates. In the Chase Mountain area where the influence of Eocene resetting is either small or minimal, the rocks had cooled to 220 ± 40 °C by about 80 Ma ago or earlier. During their cooling from metamorphic temperatures of about 500 °C, they cooled at rates between 3 and 10 °C/Ma with an average minimum cooling rate of 4 °C/Ma. Using estimated geothermal gradients, corresponding uplift rates were 0.1–0.3 km/Ma or more.Because cooling of these rocks probably took place dominantly by advection resulting from uplift and erosion, a significant portion of the total uplift of these rocks was complete by the time they reached the biotite blocking temperature, 220 °C, at least 80 Ma ago. The predominantly Late Jurassic to Early Cretaceous uplift of the complex implied by these dates has important implications for regional tectonics and models of evolution for the Omineca Crystalline Belt and adjacent areas.


2021 ◽  
Author(s):  
◽  
Gavin Holden

<p>The landscape of Northwest Nelson shows evidence of significant tectonic activity since the inception of the Austro-Pacific plate boundary in the Eocene. Evidence of subsidence followed by rapid uplift from the Eocene to the late Miocene is preserved in the sedimentary basins of Northwest Nelson. However, the effects of erosion mean there is very little evidence of post-Miocene tectonic activity preserved in the Northwest Nelson area. This is a period of particular interest, because it coincides with the onset of rapid uplift along the Alpine Fault, which is located to the south, and the very sparse published data for this period suggest very low uplift rates compared to other areas close to the Alpine Fault.  Cosmogenic nuclide burial dating of sediments preserved in Bulmer Cavern, indicate an uplift rate of 0.13mm/a from the mid-Pliocene to the start of the Pleistocene and 0.067mm/a since the start of the Pleistocene.  The Pleistocene uplift rate is similar to other published uplift rates for this period from the northern parts of Northwest Nelson, suggesting that the whole of Northwest Nelson has experienced relative tectonic stability compared to other areas close to the Alpine Fault during this period. The mid-Pliocene uplift rate is possibly the first precisely constrained uplift rate in the area for this period, and suggests that there has been a progressive decrease in uplift rates from much higher rates in the late Miocene.</p>


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