The Quaternary Transformation of Older Inherited Mountain Landscapes

2014 ◽  
Vol 48 (1) ◽  
Author(s):  
Leszek Starkel
Keyword(s):  
Chemical Weathering ◽  
Climatic Changes ◽  
Climatic Fluctuations ◽  
Cold Stage ◽  
Vertical Zone ◽  
Wind Activity ◽  
Mountain Landscapes ◽  
European Mountains ◽  
Additional Role ◽  
Planation Surfaces

AbstractThe Quaternary transformation of the inherited mountain relief was controlled by three factors: cyclic climatic changes, resistance of the substratum and neotectonic uplift. Cyclic climatic fluctuations in the majority of European mountains were reflected in the alternation of interglacial and cold stages, the former characterized by a dominance of forest and chemical weathering, the latter by permafrost, solifluction, wind activity and, at higher elevations, by glacier advances. The transitional phases played an important role as periods of re-establishment of water circulation and transfer of regolith and sediment, formed during the previous cold or interglacial stage. The rates of degradation of inherited planation surfaces and slopes depend on bedrock resistance. In the case of less resistant flysch deposits, degradation during a single (last) cold stage reached 10 metres. Therefore, the higher planation levels may have been either better preserved on more resistant bedrock or even emphasized by cryoplanation processes. The lowest piedmont developed on less resistant beds was lowered to 50 m. In the young mountains, the Quaternary uplift may have played an additional role. In the case of uplift reaching or exceeding several hundred metres, the former fluvial forms were shifted to the cryonival or even nival (glacial) vertical zone where they became entirely transformed.

scholarly journals Climatic effects on rapid chemical and physical denudation rates measured with cosmogenic nuclides in the Ōhau catchment, New Zealand

2021 ◽  
Author(s):  
◽  
Maia Bellingham
Keyword(s):  
Carbon Dioxide ◽  
New Zealand ◽  
Chemical Weathering ◽  
Southern Alps ◽  
Grain Sizes ◽  
Denudation Rates ◽  
Climate Stability ◽  
Mountain Landscapes ◽  
Carbon Dioxide Cycling

<p>Understanding how active mountain landscapes contribute to carbon dioxide cycling and influences on long-term climate stability requires measurement of weathering fluxes from these landscapes. The few measured chemical weathering rates in the Southern Alps are an order of magnitude greater than in the rest of the world. Rapid tectonic uplift coupled with extreme orographic precipitation is driving exceptionally fast chemical and physical denudation. These rates suggest that weathering in landscapes such as the Southern Alps could play a significant role in carbon dioxide cycling. However, the relative importance of climate and tectonics driving these fast rates remains poorly understood.   To address this gap, in situ ¹⁰Be derived catchment-averaged denudation rates were measured in the Ōhau catchment, Canterbury, New Zealand. Denudation rates in the Dobson Valley within the Ōhau catchment, varied from 474 – 7,570 m Myr⁻¹, aside from one sub-catchment in the upper Dobson Valley that had a denudation rate of 12,142 m Myr⁻¹. The Dobson and Hopkins Rivers had denudation rates of 1,660 and 4,400 m Myr⁻¹ respectively, in these catchments. Dobson Valley denudation rates show a moderate correlation with mean annual precipitation (R²=0.459). This correlation supports a similar trend identified at local and regional scales, and at high rates of precipitation this may be an important driver of erosion and weathering.   Sampling of four grain sizes (0.125 to > 8 mm) at one site in the Dobson Valley resulted in variability in ¹⁰Be concentrations up to a factor of 2.5, which may be a result of each grain size recording different erosional processes. These observations demonstrate the importance of assessing potential variability and the need to sample consistent grain sizes across catchments.   Chemical depletion fractions measured within soil pits in the upper Dobson Valley indicate chemical weathering contributes 30% of total denudation, and that physical erosion is driving rapid total denudation. Chemical weathering appears to surpass any proposed weathering speed limit and suggests total weathering may not be limited by weathering kinetics. This research adds to the paucity of research in New Zealand, and for the first time presents ¹⁰Be derived denudation rates from the eastern Southern Alps, with estimates of the long-term weathering flux. High weathering fluxes in the Southern Alps uphold the hypothesis that mountain landscapes play an important role in carbon dioxide cycling and long-term climate stability.</p>

scholarly journals Reflection of climatic changes during interpleniglacial in the geoecosystems of South-Eastern Poland

2017 ◽  
Vol 44 (1) ◽  
pp. 202-215 ◽  
Author(s):  
Leszek Starkel ◽  
Danuta J. Michczyńska ◽  
Piotr Gębica
Keyword(s):  
Eastern Europe ◽  
Climatic Changes ◽  
Southern Poland ◽  
Central Eastern Europe ◽  
Long Period ◽  
Aeolian Deposits ◽  
Cold Stage ◽  
Continuous Permafrost ◽  
Loess Deposition ◽  
River Valleys

Abstract About 70% of the last cold stage was taken by transitional phases of continuous fluctuations of climate and permafrost extension. All this is reflected especially well in slope types and the thickness of slope, fluvial and aeolian deposits. Very distinct and relatively fast changes took place around 33–30 ka BP: the aridification of climate with an ice sheet transgression, expansion of continuous permafrost and the onset of loess deposition. The greatest transformations of slopes and river valleys in the Carpathians and Subcarpathian Basins took place not in the coolest phases but during the Interpleniglacial. The authors exemplified a number of sites in Southern Poland documenting frequent fluctuations of climate and permafrost from that 25–30 ka long period. Calibrated dates of dated episodes correlate well with the δ18O curve from Greenland with frequent warmings. These rapid warmings are reflected in the higher rate of aggradation in valley floors and thick colluvial material deposited over slopes, both combined with a retreat of permafrost. The comparison with the Greenland 18O curve is valuable to establish a comparable chronology of events, even for such a distant area like Central-Eastern Europe.

Clay minerals in late Quaternary sediments from the south Chilean margin as indicators of provenance and palaeoclimate

Clay Minerals ◽  
2008 ◽  
Vol 43 (2) ◽  
pp. 235-253 ◽  
Author(s):  
L. Marinoni ◽  
M. Setti ◽  
C. Salvi ◽  
A. López-Galindo
Keyword(s):  
Chemical Weathering ◽  
Late Quaternary ◽  
Clay Fraction ◽  
Climatic Changes ◽  
Southern Chile ◽  
Bulk Rock ◽  
Quaternary Sediments ◽  
Glacial Retreat ◽  
Sea Level Variations ◽  
Chilean Margin

AbstractAn investigation of bulk-rock and clay-fraction compositions of two sedimentary cores from southern Chile was performed to evaluate the record of temporal climatic changes during the late Quaternary (11 ky and 30 ky BP). The bulk mineralogy shows an abundance of feldspars, mica and quartz, with lesser chlorite, amphibole and pyroxene, and variable amounts of carbonates. The clay fraction consists of illite, chlorite and scarce smectite. Smectite shows platy morphology, an Al-Fe beidellite chemical composition, and is detrital. Smectite, together with biogenic carbonate, increases in levels diagnostic of warmer phases. Increases in smectite are attributed either to the beginning of chemical weathering, allowed by the glacial retreat, or to ice extension and sea-level variations. Warmer climates also favoured the increase of carbonate productivity. Levels diagnostic of colder phases show a large decrease in carbonate, small amounts of smectite and large amounts of chlorite and mica, as the abundance of glaciers reduced the productivity and prevented chemical weathering.

Fossil coleopteran assemblages as sensitive indicators of climatic changes during the Devensian (Last) cold stage

1977 ◽  
Vol 280 (972) ◽  
pp. 313-340 ◽  
Keyword(s):  
Thermal Environment ◽  
Climatic Changes ◽  
Cold Period ◽  
Ocean Bottom ◽  
Moderate Degree ◽  
Oceanic Circulation ◽  
Insect Fauna ◽  
Climatic Fluctuations ◽  
Thermal Maximum ◽  
Asiatic Species

Goleoptera are abundant fossils in Quaternary deposits laid down under freshwater or terrestrial conditions. They display a remarkable degree of evolutionary stability and reasons are adduced for believing that this morphological constancy is associated with physiological constancy. Thus whole communities of species have been assembled in the past, drawn together by common ecological preferences, so that the species composition of fossil assemblages resembles that of modern faunas. Marked changes in the geographical distribution of Coleoptera during the last glacial-interglacial cycle conform to an orderly pattern of climatic fluctuations. The Coleoptera contribute most information about the Devensian climates during warmer interstadial periods because during the colder episodes conditions in Britain became more or less intolerable to insect life and the fossil content of the sediments approaches zero. The term interstadial is here used for an interlude of milder climate in an otherwise cold period which either does not attain temperatures equivalent to those of the present day or which attains temperatures as warm, or even warmer than those of today but which does not last long enough for floral and faunal equilibrium to become established. During the Ghelford Interstadial, at the limit of acceptable radiocarbon dating but possibly about 60000 years (a) ago, the climate in central Britain was rather cooler than now with a moderate degree of continentality. The Upton Warren Interstadial complex, between about 45000 and 25000 a ago, reached its thermal maximum at about 43000 a before present when temperatures were rather higher than those of the present day and the climate was moderately oceanic. This episode may have been as short in duration as 1000 a. After this the interstadial is characterized by a period of much lower temperatures, with a greatly increased degree of climatic continentality, lasting for about 15 000 a. Few insect faunas are known from the period of maximum ice expansion but the scant evidence supports an interpretation of a climate of arctic severity. During the closing phases of the Devensian cold period there is faunal evidence for only one major climatic oscillation - here called the Windermere Interstadial. The sharp rise in the thermal environment at its beginning took place rather before 13000 a ago but later than 14000 a ago. Thermal maximum was attained almost immediately with temperatures during the summer at or above their present day level. Moderate oceanicity of the climate at this time means that winter temperatures were not much lower than those of the present day. At least during the earliest parts of this interstadial a temperate insect fauna was associated with a flora almost entirely dominated by herbs. The decline of the Windermere Interstadial from its thermal maximum seems to have been more or less synchronous from southern to northern England and to have taken place at about 12 200 a ago. A cool temperate phase then ensued for over one thousand years with summers about 3 °G cooler than during the thermal maximum. This episode corresponds in time to the Allerod oscillation. The Loch Lomond Stadial between 11000 and 10000 a ago saw the return of arctic faunas to the British Isles even as far south as Cornwall. The presence of Asiatic species, though not abundant, suggests that the climate at this time may have been rather continental. The timing and intensity of the climatic changes during deglaciation show close parallelism to the changes in oceanic circulation in the eastern Atlantic now being interpreted from cores of ocean bottom sediments.

Reconstructing chemical weathering during the Lower Mesozoic in the Western-Central Mediterranean area: a review of geochemical proxies

2017 ◽  
Vol 155 (4) ◽  
pp. 944-954 ◽  
Author(s):  
FRANCESCO PERRI
Keyword(s):  
Rift Valley ◽  
Chemical Weathering ◽  
Mineralogical Composition ◽  
Mediterranean Area ◽  
Climatic Changes ◽  
Central Mediterranean ◽  
Geochemical Proxies ◽  
Chemical Index ◽  
Chemical Index Of Alteration ◽  
Mineralogical Compositions

AbstractThe Triassic–Jurassic rift-valley stage of Tethyan rifting in the Western-Central Mediterranean area is characterized by a development of a puzzle of plates and microplates with the deposition of continental redbeds (in the internal domains of the Gibraltar Arc and Calabria–Peloritani Arc) that can be considered a regional lithosome. This paper aims to reconstruct the chemical weathering conditions of the Triassic–Jurassic boundary in the Western-Central Mediterranean area using the geochemical and mineralogical composition of continental redbed mudrocks of Mesozoic age. The mudrocks from the Calabria–Peloritani Arc show higher values of weathering (mobility) indices (αMg=(Al/Mg)sed/(Al/Mg)UCC;αK=(Th/K)sed/(Th/K)UCC;αBa=(Th/Ba)sed/(Th/Ba)UCC) than the Gibraltar Arc samples. Furthermore, the CIA (Chemical Index of Alteration) and MIA (Mineralogical Index of Alteration) values and the ‘Rb-type indices’ (e.g. Rb/Sr and Rb/K ratios) are higher for the Calabria–Peloritani Arc mudrocks than the Gibraltar Arc samples. All these geochemical proxies closely resemble each other and show similar variations suggesting climatic changes towards humid conditions through the Uppermost Triassic to Lowermost Jurassic that favoured chemical weathering conditions. This period is probably characterized by seasonal climate alternations corresponding to an increase in palaeoclimatic humidity. The mineralogical compositions of the Mesozoic mudrocks further confirm these indications as shown by a higher abundance of kaolinite, related to warm–humid conditions, in the Calabria–Peloritani Arc mudrocks than in those of the Gibraltar Arc.

scholarly journals Climate vulnerability index fluctuation: a case of Iran

2018 ◽  
Vol 10 (1) ◽  
pp. 223-235
Author(s):  
Hakimeh Hatef ◽  
Mahmoud Daneshvar Kakhki ◽  
Mohammad Reza Kohansal ◽  
Mohammad Bannayan ◽  
Naser Shahnoushi Froshani
Keyword(s):  
Vulnerability Index ◽  
Climatic Changes ◽  
Climatic Parameters ◽  
Climatic Zones ◽  
Climatic Fluctuations ◽  
Wind Fluctuation ◽  
Climate Vulnerability ◽  
Weather Stations ◽  
Climate Vulnerability Index ◽  
Different Sources

Abstract Climatic fluctuations have severe effects on water and soil resources and economy as a whole. It is hence important to study the fluctuations of climatic parameters in different regions in order to recognize the source and type of parameter that have led to fluctuating climatic parameters. To achieve this goal, the current study attempts to address the following issues: what are the different sources of fluctuations in climate parameters? Do different regions have the same degree of vulnerability and what is the most fluctuating parameter in each region? To answer these questions, the study suggests climate vulnerability index fluctuation. Calculating the index requires data provided by weather stations, so 115 weather stations were divided into 12 climatic zones based on the availability of data. This index considered permanent and frequent temperature, precipitation, storm and aridity shocks. The results indicated that the maximum rank of index has occurred in hot semi-mountainous and very hot desert. Also, temperature fluctuation was the major factor in five regions, whereas wind fluctuation was the major factor in three regions. Generally, the northern and western parts of the country experienced minimum climatic changes. Moving towards southern regions of the country, more climatic changes were observed.

The influence of changes in sea level on coastal cliff instability in Devon

1991 ◽  
Vol 7 (1) ◽  
pp. 361-367 ◽  
Author(s):  
P. G. Kalaugher ◽  
P. Grainger
Keyword(s):  
Sea Level ◽  
Climatic Changes ◽  
Future Trends ◽  
Quaternary Deposits ◽  
Climatic Fluctuations ◽  
Sea Levels ◽  
Landslide Hazards ◽  
Coastal Cliff ◽  
Shore Platforms

AbstractMajor variations in sea level have resulted from climatic changes during the Quaternary. In addition, beyond the maximum limit of glaciation, periglacial climates in southern Britain have produced Quaternary deposits which can affect the nature of coastal slopes and their response to marine erosion. Examples are given of cliffs in head (solifluction) deposits which overlie raised shore platforms in Devon. The present styles and distribution of coastal landslide hazards, recorded in recent surveys, are directly related to past Quaternary sea levels and climatic fluctuations. Future trends in relative sea level are a significant factor in the determination of the hazards in the longer term, as there could be changes in the level at which marine erosion is effective. Rankings of the hazards, which should in any case be updated routinely by repeated monitoring of the landslide activity, ought to reflect expected changes in sea level.

scholarly journals Climatic effects on rapid chemical and physical denudation rates measured with cosmogenic nuclides in the Ōhau catchment, New Zealand

2021 ◽  
Author(s):  
◽  
Maia Bellingham
Keyword(s):  
Carbon Dioxide ◽  
New Zealand ◽  
Chemical Weathering ◽  
Southern Alps ◽  
Grain Sizes ◽  
Denudation Rates ◽  
Climate Stability ◽  
Mountain Landscapes ◽  
Carbon Dioxide Cycling

<p>Understanding how active mountain landscapes contribute to carbon dioxide cycling and influences on long-term climate stability requires measurement of weathering fluxes from these landscapes. The few measured chemical weathering rates in the Southern Alps are an order of magnitude greater than in the rest of the world. Rapid tectonic uplift coupled with extreme orographic precipitation is driving exceptionally fast chemical and physical denudation. These rates suggest that weathering in landscapes such as the Southern Alps could play a significant role in carbon dioxide cycling. However, the relative importance of climate and tectonics driving these fast rates remains poorly understood.   To address this gap, in situ ¹⁰Be derived catchment-averaged denudation rates were measured in the Ōhau catchment, Canterbury, New Zealand. Denudation rates in the Dobson Valley within the Ōhau catchment, varied from 474 – 7,570 m Myr⁻¹, aside from one sub-catchment in the upper Dobson Valley that had a denudation rate of 12,142 m Myr⁻¹. The Dobson and Hopkins Rivers had denudation rates of 1,660 and 4,400 m Myr⁻¹ respectively, in these catchments. Dobson Valley denudation rates show a moderate correlation with mean annual precipitation (R²=0.459). This correlation supports a similar trend identified at local and regional scales, and at high rates of precipitation this may be an important driver of erosion and weathering.   Sampling of four grain sizes (0.125 to > 8 mm) at one site in the Dobson Valley resulted in variability in ¹⁰Be concentrations up to a factor of 2.5, which may be a result of each grain size recording different erosional processes. These observations demonstrate the importance of assessing potential variability and the need to sample consistent grain sizes across catchments.   Chemical depletion fractions measured within soil pits in the upper Dobson Valley indicate chemical weathering contributes 30% of total denudation, and that physical erosion is driving rapid total denudation. Chemical weathering appears to surpass any proposed weathering speed limit and suggests total weathering may not be limited by weathering kinetics. This research adds to the paucity of research in New Zealand, and for the first time presents ¹⁰Be derived denudation rates from the eastern Southern Alps, with estimates of the long-term weathering flux. High weathering fluxes in the Southern Alps uphold the hypothesis that mountain landscapes play an important role in carbon dioxide cycling and long-term climate stability.</p>

scholarly journals A change in the status of the Greenland Inland Ice

1991 ◽  
Vol 152 ◽  
pp. 39-41
Author(s):  
A Weidick
Keyword(s):  
Electric Power ◽  
Climatic Change ◽  
Time Scale ◽  
Climatic Changes ◽  
Climatic Fluctuations ◽  
The Past ◽  
The Status ◽  
Routine Basis ◽  
Inland Ice

Observations on the status of the Greenland ice cover are registered at the Geological Survey of Greenland (GGU) on a routine basis. During the past two decades studies have been particularly related to technical activities such as hydro-electric power, but more recently there has been increasing interest in the significance of glacier variations as indicators of climatic change. However, whereas local glacier variations are usually related to climatic changes on the time scale of a few decades or centuries, documented changes in the status of the margins of the Inland Ice in the literature are mainly related to long term climatic fluctuations on the time scale of thousands of years or more.

Effect of climatic fluctuations on the distribution of warm-water coral Astroides calycularis in the Adriatic Sea: new records and review

2004 ◽  
Vol 84 (3) ◽  
pp. 599-602 ◽  
Author(s):  
Ivana Grubelić ◽  
Boris Antolić ◽  
Marija Despalatović ◽  
Branka Grbec ◽  
Gordana Beg Paklar
Keyword(s):  
Adriatic Sea ◽  
Variable Temperature ◽  
Current System ◽  
Climatic Changes ◽  
Warm Water ◽  
Climatic Fluctuations ◽  
The North ◽  
Adriatic Coast ◽  
The North Atlantic Oscillation ◽  
Water Coral

Three colonies of warm-water coral Astroides calycularis were found at the eastern part of the middle Adriatic Sea during the 1990–2001 period. For each specimen, depth distribution and habitat were recorded. Previous and recent knowledge of this species in the Adriatic Sea and in the Mediterranean Sea was discussed in relation to climatic changes. Occurrence of A. calycularis in the Adriatic Sea was related to the increased temperatures of the surface marine layer. Variable temperature conditions were connected to the climatic changes on the hemispheric scale through the North Atlantic Oscillation index. The prevailing sea current system together with the coastal configuration and bottom type favours the presence of the studied warm-water coral on the eastern Adriatic coast.

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