Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints

Long- to short-term denudation rates in the southern Apennines: geomorphological markers and chronological constraints Age constraints of geomorphological markers and consequent estimates of long- to short-term denudation rates from southern Italy are given here. Geomorphic analysis of the valley of the Tanagro River combined with apatite fission track data and radiometric dating provided useful information on the ages and evolution of some significant morphotectonic markers such as regional planated landscapes, erosional land surfaces and fluvial terraces. Reconstruction of paleotopography and estimation of the eroded volumes were perfomed starting from the plano-altimetric distribution of several orders of erosional land surfaces surveyed in the study area. Additional data about denudation rates related to the recent and/or active geomorphological system have been obtained by estimating the amount of suspended sediment yield at the outlet of some catchments using empirical relationships based on the hierarchical arrangement of the drainage network. Denudation rates obtained through these methods have been compared with the sedimentation rates calculated for two adjacent basins (the Pantano di San Gregorio and the Vallo di Diano), on the basis of published tephrochronological constraints. These rates have also been compared with those calculated for the historical sediment accumulation in a small catchment located to the north of the study area, with long-term exhumation data from thermochronometry, and with uplift rates from the study area. Long- and short-term denudation rates are included between 0.1 and 0.2 mm/yr, in good agreement with regional data and long-term sedimentation rates from the Vallo di Diano and the Pantano di San Gregorio Magno basins. On the other hand, higher values of exhumation rates from thermochronometry suggest the existence of past erosional processes faster than the recent and present-day exogenic dismantling. Finally, the comparison between uplift and denudation rates indicates that the fluvial erosion did not match the tectonic uplift during the Quaternary in this sector of the chain. The axial zone of the southern Apennines should therefore be regarded as a landscape in conditions of geomorphological disequilibrium.

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Denudation rates derived from spatially-averaged cosmogenic nuclide analysis in Nelson/Tasman catchments, South Island, New Zealand

10.26686/wgtn.17008099.v1 ◽

2021 ◽

Author(s):

◽

Abby Jade Burdis

Keyword(s):

New Zealand ◽

Dynamic Environment ◽

Low Frequency ◽

Short Term ◽

Erosion Rates ◽

Cosmogenic Nuclide ◽

Denudation Rates ◽

Conventional Methods

New Zealand’s tectonically and climatically dynamic environment generates erosion rates that outstrip global averages by up to ten times in some locations. In order to assess recent changes in erosion rate, and also to predict future erosion dynamics, it is important to quantify long-term, background erosion. Current research on erosion in New Zealand predominantly covers short-term (100 yrs) erosion dynamics and Myr dynamics from thermochronological proxy data. Without competent medium-term denudation data for New Zealand, it is uncertain which variables (climate, anthropogenic disturbance of the landscape, tectonic uplift, lithological, or geomorphic characteristics) exert the dominant control on denudation in New Zealand. Spatially-averaged cosmogenic nuclide analysis can effectively offer this information by providing averaged rates of denudation on millennial timescales without the biases and limitations of short-term erosion methods. Basin-averaged denudation rates were obtained in the Nelson/Tasman region, New Zealand, from analysis of concentrations of meteoric ¹⁰Be in silt and in-situ produced ¹⁰Be in quartz. The measured denudation rates integrate over ~2750 yrs (in-situ) and ~1200 yrs (meteoric). Not only do the ¹⁰Be records produce erosion rates that are remarkably consistent with each other, but they are also independent of topographic metrics. Denudation rates range from ~112 – 298 t km⁻² yr⁻¹, with the exception of one basin which is eroding at 600 - 800 t km⁻² yr⁻¹. The homogeneity of rates and absence of a significant correlation with geomorphic or lithological characteristics could indicate that the Nelson/Tasman landscape is in (or approaching) a topographic steady state. Millennial term (¹⁰Be-derived) denudation rates are more rapid than those inferred from other conventional methods in the same region (~50 – 200 t km⁻² yr⁻¹). This is likely the result of the significant contribution of low frequency, high magnitude erosive events to overall erosion of the region. Both in-situ and meteoric ¹⁰Be analyses have the potential to provide competent millennial term estimates of natural background rates of erosion. This will allow for the assessment of geomorphic-scale impacts such as topography, tectonics, climate, and lithology on rates of denudation for the country where many conventional methods do not. Cosmogenic nuclides offer the ability to understand the response of the landscape to these factors in order to make confident erosion predictions for the future.

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Evaluating the stability and evolution of a proposed post mining landform.

10.5194/egusphere-egu21-8569 ◽

2021 ◽

Author(s):

Welivitiyage Don Dimuth Prasad Welivitiya ◽

Garry Willgoose ◽

Gregory Hancock

Keyword(s):

Cross Sections ◽

Soil Profile ◽

Evolution Model ◽

Short Term ◽

Landform Evolution ◽

Erosion Rates ◽

Denudation Rates ◽

Land Denudation ◽

Profile Characteristics

Evaluating the future stability and land denudation rates of natural or anthropogenic landforms is paramount for sustainable land use practices. Landform evolution models can be powerful tools in this endeavour.&#160; In this study we used the well-established landform evolution model SIBERIA and the newly developed coupled soilscape-landform evolution model SSSPAM to simulate the evolution of a proposed post mining landform. SIBERIA uses a cellular digital elevation model to simulate annual average fluvial and diffusive erosion on landforms using annual average precipitation. However it does not simulate the soil profile evolution on the evolving landform. The new SSSPAM coupled soilscape-landform evolution model has the ability to assess the overall erosion rates of catchment scale landforms either using short term precipitation events, variable precipitation or time averaged precipitation rates. In addition, SSSPAM is able to simulate the evolution of the soil profile of the evolving landform using pedogenetic processes such as physical weathering and armouring.&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160;&#160; To assess the reliability of SSSPAM, model predictions at 100 and 10000 years were compared with SIBERIA predictions at the same times. During the long term (10000yr) simulation the effect of armouring and weathering on the landform evolution was also assessed. The results obtained from these different simulations were compared and contrasted. Comparison of the short term simulations revealed that SSSPAM results compare well with the simulation results of the more established SIBERIA model. Long term simulation showed that SSSPAM simulation results also compares well with SIBERIA simulations while the erosion rates predicted by both models are close to the land denudation rates measured in the field. The soil profile characteristics and channel forms simulated by SSSPAM long term simulations were examined using several landform cross-sections. This analyses revealed that SSSPAM produces deep incised channels with very low soil thickness in upper reaches of the catchment and shallow channels with relatively thick soil layers in the lower reaches of the catchment. These SSSPAM simulated channels match well with the channel forms and distribution of bedrock channels and alluvial channels observed in the field. The analysis of the catchment cross-sections also showed that SSSPAM is capable of reproducing complex subsurface soil evolution and stratification and spatial variability of soil profile characteristics typically observed in the field.

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Long-term nivation rates, Cathedral Massif, northwestern British Columbia

Canadian Journal of Earth Sciences ◽

10.1139/cjes-2019-0176 ◽

2020 ◽

Vol 57 (11) ◽

pp. 1305-1311 ◽

Cited By ~ 1

Author(s):

Kelsey E. Nyland ◽

Frederick E. Nelson

Keyword(s):

British Columbia ◽

Contemporary Literature ◽

Short Term ◽

Denudation Rates ◽

History Of ◽

Aerial Vehicle ◽

The Last Glacial Maximum ◽

East West ◽

The Last Glacial

Cryoplanation terraces (CTs) are large (3000–800 000 m2) erosional landforms found in upland periglacial environments. Two hypotheses for the formation of CTs are supported in contemporary literature: (1) CT formation is controlled primarily by geologic structure; and (2) CTs are climatically controlled through nivation, a suite of erosional processes associated with late-lying snowbanks. A persistent question in periglacial geomorphology is whether nivation can produce CT-scale landforms. This paper examines the unusual deglaciation history of “Frost Ridge” on the Cathedral Massif, northwestern British Columbia, to estimate long-term denudation attributable to nivation processes active since the last glacial maximum. Frost Ridge forms one flank of an east–west-oriented glacial valley. During deglaciation, marginal drainage created V-shaped erosional notches on both valley walls. Minimization of solar radiation on the steep north-facing wall (Frost Ridge) allowed snowbanks to accumulate and persist in the marginal drainage features and nivation processes to erode the slope. Today, several large nivation hollows (incipient CTs) are present near the summit of Frost Ridge, while the V-shaped marginal drainage features are preserved at lower elevations and on the opposite, south-facing valley wall. A high-resolution survey using an unmanned aerial vehicle (UAV) allowed volumes of marginal drainage and incipient terrace features to be compared. Based on this volumetric comparison, denudation rates are estimated to range from 4.2 to 125.8 mm/kyr, which are comparable with relatively short-term nivation rates reported from Antarctica and mid-latitude alpine periglacial areas.

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Sediment accumulation in a series of four pilot-scale stabilization ponds

Water Science & Technology ◽

10.2166/wst.1994.0425 ◽

1994 ◽

Vol 30 (8) ◽

pp. 281-284

Author(s):

A. Ghrabi ◽

M. Ferchichi

Keyword(s):

Sediment Accumulation ◽

Pilot Scale ◽

Sediment Depth ◽

Short Term ◽

Stabilization Ponds ◽

Volatile Solids ◽

The Mean ◽

Depth Increase

Settling and accumulation of sediments have been measured on the bottom of the facultative and three maturation ponds of a series of pilot-scale stabilization ponds. The mean deposition rate in the facultative pond showed that the attempt to establish a short-term sedimentation by in situ measurements failed. The rates were largely overestimated and the values calculated from the sediment accumulated in a long-term are closer to the reality. The sediment depth increase rates are 5 cm/year for the facultative pond and 1.3 cm/year for second and third maturation ponds. In the last maturation pond it is 1.6 cm/year. The rate of sediments deposit (volatile solids) in the first pond can be estimated by an at−b equation.

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Long-term and short-term vertical velocity profiles across the forearc in the NE Japan subduction zone

Quaternary Research ◽

10.1016/j.yqres.2008.12.005 ◽

2009 ◽

Vol 71 (2) ◽

pp. 227-238 ◽

Cited By ~ 26

Author(s):

Tabito Matsu'ura ◽

Akira Furusawa ◽

Hidetaka Saomoto

Keyword(s):

Velocity Profile ◽

Vertical Velocity ◽

Late Quaternary ◽

Crustal Thickening ◽

Height Distribution ◽

Uplift Rate ◽

Short Term ◽

Fluvial Terraces ◽

Vertical Velocity Profile

AbstractWe estimated the long-term vertical velocity profile across the northeastern Japan forearc by using the height distribution of late Quaternary marine and fluvial terraces, and we correlated the ages of the two marine terraces with marine isotope stages (MIS) 5.5 and 5.3 or 5.1 by cryptotephra stratigraphy. The uplift rate, estimated as 0.11–0.19 m ka− 1 from the relative heights between the terrace surfaces and eustatic sea levels, was nearly equal to, or slightly slower than, the uplift rate farther inland (0.15–0.19 m ka− 1), as determined from the relative heights of fill terrace surfaces. In contrast, the short-term vertical velocity profile, obtained from GPS observations, showed that the forearc is currently subsiding at a maximum rate of 5.4 ± 0.4 mm yr− 1. Thus, the current short-term (geodetic) subsidence does not reflect long-term (geological) tectonic movement. Short-term vertical deformation is probably driven by subduction erosion or elastic deformation caused by interplate coupling, or both. However, long-term uplift is probably due not to moment release on the mega-thrust but to crustal thickening.

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Sedimentação de Longo e Curto Período na Lagoa dos Patos, Sul do Brasil

Pesquisas em Geociências ◽

10.22456/1807-9806.19516 ◽

2006 ◽

Vol 33 (2) ◽

pp. 79 ◽

Cited By ~ 12

Author(s):

ELÍRIO TOLDO JR ◽

SERGIO DILLENBURG ◽

IRAN CORRÊA ◽

LUIZ ALMEIDA ◽

JAIR WESCHENFELDER ◽

...

Keyword(s):

Coastal Plain ◽

Average Rate ◽

Stratigraphic Correlation ◽

Sedimentation Rates ◽

Southern Brazil ◽

Rio Grande Do Sul ◽

Short Term ◽

European Colonization ◽

Reflecting Surface

Lagoa dos Patos in southern Brazil is part of the largest lagoonal system in South America. The Holocene lagoonal sediments of the Lagoa dos Patos, mostly muds, have an average thickness of about 6 m as determined by 297 km of 7.0 kHz echograms. Holocene muddy sedimentation developed over a probable Upper Pleistocene coastal plain, whose surface has a subbottom reflector that could not be penetrated by the energy of a 7.0 kHz seismic wave. The characteristics of this reflecting surface suggest indurated Pleistocene muds and/or sediments that are coarser than the overlying muddy deposits of Holocene lagoon. Based on stratigraphic correlation and the local sea level curve, we estimate that Holocene sedimentation started about 8.0 ka ago. This yields an average deposition rate of 0.75 mm/yr. A broadly comparable average rate of 0.52 ± mm/yr was obtained for cored intervals between 14C samples from the upper part of these muddy Holocene lagoon deposits. These long-term sedimentation rates are much slower than rates based on two determinations of 210Pb for surface muds deposits in the last 150 years, which yielded values of 3.5 and 8.3 mm/yr. Quite possibly the high short-term rates may be the result of more rapid lagoonal sedimentation related to deforestation of the watershed of the lagoon and other impact types related with human activities during the 150 years of European colonization in the Rio Grande do Sul state. Also, the aim of this study is to identify present and possible future environmental problems related with high lagoonal sedimentation rates such as the water quality, port dredge and the presence of mud deposits on the oceanic beach.

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Willow recruitment and channel patterns in beaver dominated stream systems

10.5194/egusphere-egu2020-1210 ◽

2020 ◽

Author(s):

Rebekah Levine ◽

Megan Tarmichael ◽

Grant Meyer

Keyword(s):

Sediment Accumulation ◽

Plant Colonization ◽

Point Bar ◽

Migration Rates ◽

Southwestern Montana ◽

Fluvial Terraces ◽

Point Bars ◽

Channel Patterns ◽

Stream Systems

Beaver activity can segment a stream corridor through dam building which locally affects channel slope and sediment transport. &#160;We have found, however, that long-term beaver presence within a river corridor has impacts beyond dam sites that affect system-wide stream morphodynamics and riparian willow recruitment. Along study streams (basin areas 20 &#8211; 125 km2) in southwestern Montana, USA, beaver-chewed willow stems (beaver cuttings) from dam construction, food caches and herbivory float downstream and commonly accumulate within 1 km of dam sites. At the 90 randomly selected sites surveyed, beaver cuttings accumulated on 81% of point bar sites and 51% of all surveyed sites. The accumulated beaver cuttings can sprout, adding roughness, thus enhancing sediment accumulation on point bars and at abandoned dam sites. Sprouting stems were present at 25% of all sites, indicating that beaver cuttings commonly provide a secondary pathway for willow recruitment and influence sediment dynamics.As beaver cuttings and sediment accumulate on point bars, the channel migrates laterally, burying the cuttings. High resolution aerial imagery has been used to calculate migration rates for twenty-six 200 m reaches in the study streams. Migration rates range from 0.07 &#8211; 2.91 m/yr (mean 0.43 m/yr) over a 14 year period from 1995-2009. Thirty-four radiocarbon (14C) ages found in fluvial terraces 1.2 &#8211; 3 m above the bankfull channel, show that beaver cuttings range in age from ~6030 &#8211; 380 cal yr BP, demonstrating that deposition and burial of beaver cuttings on point bars has been a common process over millennia. The long-term preservation of beaver-chewed wood in point-bar sequences also attests to the importance of beaver activity for enhancing carbon storage in beaver-occupied stream systems.The mosaic of sites created by beaver includes intact dams, recently breached or abandoned dams, and long-abandoned dams, interspersed with reaches unsuitable for beaver. The beaver produced habitat heterogeneity interacts with sediment and beaver cutting transport to enhance riparian plant colonization and meander development.

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Testing the Prediction Ability of LEM-Derived Sedimentary Budget in an Upland Catchment of the Southern Apennines, Italy: A Source to Sink Approach

Water ◽

10.3390/w11050911 ◽

2019 ◽

Vol 11 (5) ◽

pp. 911 ◽

Cited By ~ 4

Author(s):

Gioia ◽

Lazzari

Keyword(s):

Sediment Flux ◽

Southern Apennines ◽

Short Term ◽

Prediction Ability ◽

Small Catchment ◽

Bathymetric Survey ◽

Landscape Modification ◽

Source To Sink ◽

Natural Landscapes ◽

Sedimentary Budget

Landscape evolution models (LEMs) represent one of the most promising approaches to evaluate sedimentary budget, although factors such as the high number of parameters or the difficulty evaluating the robustness of the results can represent a limitation in their application in natural landscapes. In this paper, the Caesar–Lisflood LEM has been applied in a small catchment (i.e., about 9 km2) of southern Italy draining an artificial reservoir in order to test its ability to predict sediment flux and erosion rate. Short-term (i.e., about 20 years) estimation of the sediment volumes accumulated in the reservoir has been reconstructed by a bathymetric survey and compared to the results coming from the coeval LEM simulations. Results indicate a good accordance between LEM-based erosion volume estimations and direct sedimentation assessment, thus testifying to the high potential of such models to solve issues of sedimentary budget and short-term landscape modification.

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Denudation rates derived from spatially-averaged cosmogenic nuclide analysis in Nelson/Tasman catchments, South Island, New Zealand

10.26686/wgtn.17008099 ◽

2021 ◽

Author(s):

◽

Abby Jade Burdis

Keyword(s):

New Zealand ◽

Dynamic Environment ◽

Low Frequency ◽

Short Term ◽

Erosion Rates ◽

Cosmogenic Nuclide ◽

Denudation Rates ◽

Conventional Methods

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Conceptual short-term memory (CSTM) supports core claims of Christiansen and Chater

Behavioral and Brain Sciences ◽

10.1017/s0140525x15000928 ◽

2016 ◽

Vol 39 ◽

Author(s):

Mary C. Potter

Keyword(s):

Working Memory ◽

Rapid Serial Visual Presentation ◽

Language Comprehension ◽

Short Term Memory ◽

Visual Presentation ◽

Long Term Memory ◽

Short Term ◽

Term Memory ◽

Use Of Knowledge

AbstractRapid serial visual presentation (RSVP) of words or pictured scenes provides evidence for a large-capacity conceptual short-term memory (CSTM) that momentarily provides rich associated material from long-term memory, permitting rapid chunking (Potter 1993; 2009; 2012). In perception of scenes as well as language comprehension, we make use of knowledge that briefly exceeds the supposed limits of working memory.

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