Late Quaternary soil erosion and landscape development in the Apennine region (central Italy)

2013 ◽  
Vol 312 ◽  
pp. 96-108 ◽  
Author(s):  
Pasquale Borrelli ◽  
Philipp Hoelzmann ◽  
Daniel Knitter ◽  
Brigitta Schütt
Keyword(s):  
Soil Erosion ◽  
Late Quaternary ◽  
Central Italy ◽  
Landscape Development

Quantification of excess 231Pa in late Quaternary igneous baddeleyite

2020 ◽  
Vol 105 (12) ◽  
pp. 1830-1840 ◽  
Author(s):  
Yi Sun ◽  
Axel K. Schmitt ◽  
Lucia Pappalardo ◽  
Massimo Russo
Keyword(s):  
Late Quaternary ◽  
Central Italy ◽  
Direct Analysis ◽  
Weight Percent ◽  
Volcanic Field ◽  
Distribution Coefficients ◽  
Secular Equilibrium ◽  
Melt Distribution ◽  
D Values ◽  
Significant Figures

Abstract Initial excess protactinium (231Pa) is a frequently suspected source of discordance in baddeleyite (ZrO2) geochronology, which limits accurate U/Pb dating, but such excesses have never been directly demonstrated. In this study, Pa incorporation in late Holocene baddeleyite from Somma-Vesuvius (Campanian Volcanic Province, central Italy) and Laacher See (East Eifel Volcanic Field, western Germany) was quantified by U-Th-Pa measurements using a large-geometry ion microprobe. Baddeleyite crystals isolated from subvolcanic syenites have average U concentrations of ~200 ppm and are largely stoichiometric with minor abundances of Nb, Hf, Ti, and Fe up to a few weight percent. Measured (231Pa)/(235U) activity ratios are significantly above the secular equilibrium value of unity and range from 3.4(8) to 14.9(2.6) in Vesuvius baddeleyite and from 3.6(9) to 8.9(1.4) in Laacher See baddeleyite (values within parentheses represent uncertainties in the last significant figures reported as 1σ throughout the text). Crystallization ages of 5.12(56) ka (Vesuvius; MSWD = 0.96, n = 12) and 15.6(2.0) ka (Laacher See; MSWD = 0.91, n = 10) were obtained from (230Th)/(238U) disequilibria for the same crystals, which are close to the respective eruption ages. Applying a corresponding age correction indicates average initial (231Pa)/(235U)0 of 8.8(1.0) (Vesuvius) and 7.9(5) (Laacher See). For reasonable melt activities, model baddeleyite-melt distribution coefficients of DPa/DU = 5.8(2) and 4.1(2) are obtained for Vesuvius and Laacher See, respectively. Speciation-dependent (Pa4+ vs. Pa5+) partitioning coefficients (D values) from crystal lattice strain models for tetra- and pentavalent proxy ions significantly exceed DPa/DU inferred from direct analysis of 231Pa for Pa5+. This is consistent with predominantly reduced Pa4+ in the melt, for which D values similar to U4+ are expected. Contrary to common assumptions, baddeleyite-crystallizing melts from Vesuvius and Laacher See appear to be dominated by Pa4+ rather than Pa5+. An initial disequilibrium correction for baddeleyite geochronology using DPa/DU = 5 ± 1 is recommended for oxidized phonolitic melt compositions.

scholarly journals Seismogenesis in Central Apennines, Italy: an integrated analysis of minor earthquake sequences and structural data in the Amatrice-Campotosto area

2009 ◽  
Vol 47 (6) ◽  
Author(s):  
P. Boncio ◽  
G. Lavecchia ◽  
G. Milana ◽  
B. Rozzi
Keyword(s):  
Late Quaternary ◽  
Central Italy ◽  
Normal Fault ◽  
Structural Data ◽  
Integrated Analysis ◽  
Fault Plane Solutions ◽  
Small Magnitude ◽  
Fault Surface ◽  
Displacement Profile ◽  
Earthquake Sequences

We present a seismotectonic study of the Amatrice-Campotosto area (Central Italy) based on an integrated analysis of minor earthquake sequences, geological data and crustal rheology. The area has been affected by three small-magnitude seismic sequences: August 1992 (M=3.9), June 1994 (M=3.7) and October 1996 (M=4.0). The hypocentral locations and fault plane solutions of the 1996 sequence are based on original data; the seismological features of the 1992 and 1994 sequences are summarised from literature. The active WSWdipping Mt. Gorzano normal fault is interpreted as the common seismogenic structure for the three analysed sequences. The mean state of stress obtained by inversion of focal mechanisms (WSW-ENE-trending deviatoric tension) is comparable to that responsible for finite Quaternary displacement, showing that the stress field has not changed since the onset of extensional tectonics. Available morphotectonic data integrated with original structural data show that the Mt. Gorzano Fault extends for ~28 km along strike. The along-strike displacement profile is typical of an isolated fault, without significant internal segmentation. The strong evidence of late Quaternary activity in the southern part of the fault (with lower displacement gradient) is explained in this work in terms of displacement profile readjustment within a fault unable to grow further laterally. The depth distribution of seismicity and the crustal rheology yield a thickness of ~15 km for the brittle layer. An area of ~530 km2 is estimated for the entire Mt. Gorzano Fault surface. In historical times, the northern portion of the fault was probably activated during the 1639 Amatrice earthquake (I = X, M~ 6.3), but this is not the largest event we expect on the fault. We propose that a large earthquake might activate the entire 28 km long Mt. Gorzano Fault, with an expected Mmax up to 6.7.

Late Quaternary landscape development at the margin of the Pomeranian phase (MIS 2) near Lake Wygonin (Northern Poland)

CATENA ◽  
2015 ◽  
Vol 124 ◽  
pp. 28-44 ◽  
Author(s):  
Florian Hirsch ◽  
Anna Schneider ◽  
Alexander Nicolay ◽  
Mirosław Błaszkiewicz ◽  
Jarosław Kordowski ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Landscape Development ◽  
Northern Poland

Late Quaternary Eolian Deposition in Central Italy

2000 ◽  
Vol 54 (2) ◽  
pp. 246-252 ◽  
Author(s):  
Biancamaria Narcisi
Keyword(s):  
North Africa ◽  
Late Holocene ◽  
Late Quaternary ◽  
Ice Core ◽  
Central Italy ◽  
Last Interglacial ◽  
Central Mediterranean ◽  
Volcanic Lakes ◽  
Dust Loading ◽  
The Antarctic

Records of eolian quartz from two continuous sediment sequences drilled in Lagaccione and Lago di Vico volcanic lakes in central Italy contribute to the knowledge of eolian deposition in the central Mediterranean during the last 100,000 years. The chronology is based on 14C and 40Ar/39Ar dating and tephra analysis. Pollen data provide the paleoenvironmental framework and enable correlation between the cores. Eolian inputs were high during the steppe phases corresponding to oxygen isotope stages 4 and 2. Low inputs correspond to the forest phases of the last interglacial and the middle Holocene. Eolian inputs have increased in the late Holocene. Patterns of eolian deposition in central Italy resemble the Antarctic dust record from the Vostok ice core. The Italian patterns may also correspond with hydrological changes registered in North Africa. The main source of dust loading over the Mediterranean now, North Africa, may have played an important role in dust supply throughout the last climatic cycle.

scholarly journals Multiple Lines of Evidence for a Potentially Seismogenic Fault Along the Central-Apennine (Italy) Active Extensional Belt–An Unexpected Outcome of the MW6.5 Norcia 2016 Earthquake

2021 ◽  
Vol 9 ◽  
Author(s):  
Federica Ferrarini ◽  
Rita de Nardis ◽  
Francesco Brozzetti ◽  
Daniele Cirillo ◽  
J Ramón Arrowsmith ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Tectonic Setting ◽  
Central Italy ◽  
Stress Transfer ◽  
Normal Fault ◽  
Normal Faults ◽  
Coulomb Stress ◽  
Seismic Sequence ◽  
Seismogenic Fault ◽  
Seismogenic Source

The Apenninic chain, in central Italy, has been recently struck by the Norcia 2016 seismic sequence. Three mainshocks, in 2016, occurred on August 24 (MW6.0), October 26 (MW 5.9) and October 30 (MW6.5) along well-known late Quaternary active WSW-dipping normal faults. Coseismic fractures and hypocentral seismicity distribution are mostly associated with failure along the Mt Vettore-Mt Bove (VBF) fault. Nevertheless, following the October 26 shock, the aftershock spatial distribution suggests the activation of a source not previously mapped beyond the northern tip of the VBF system. In this area, a remarkable seismicity rate was observed also during 2017 and 2018, the most energetic event being the April 10, 2018 (MW4.6) normal fault earthquake. In this paper, we advance the hypothesis that the Norcia seismic sequence activated a previously unknown seismogenic source. We constrain its geometry and seismogenic behavior by exploiting: 1) morphometric analysis of high-resolution topographic data; 2) field geologic- and morphotectonic evidence within the context of long-term deformation constraints; 3) 3D seismological validation of fault activity, and 4) Coulomb stress transfer modeling. Our results support the existence of distributed and subtle deformation along normal fault segments related to an immature structure, the Pievebovigliana fault (PBF). The fault strikes in NNW-SSE direction, dips to SW and is in right-lateral en echelon setting with the VBF system. Its activation has been highlighted by most of the seismicity observed in the sector. The geometry and location are compatible with volumes of enhanced stress identified by Coulomb stress-transfer computations. Its reconstructed length (at least 13 km) is compatible with the occurrence of MW≥6.0 earthquakes in a sector heretofore characterized by low seismic activity. The evidence for PBF is a new observation associated with the Norcia 2016 seismic sequence and is consistent with the overall tectonic setting of the area. Its existence implies a northward extent of the intra-Apennine extensional domain and should be considered to address seismic hazard assessments in central Italy.

Importância do Estudo das Vertentes

GEOgraphia ◽  
2009 ◽  
Vol 4 (8) ◽  
pp. 79 ◽  
Author(s):  
Antônio Veloso
Keyword(s):  
Soil Erosion ◽  
Slope Stability ◽  
Land Surface ◽  
Construction Projects ◽  
Flowing Water ◽  
Landscape Development ◽  
Natural Processes ◽  
The Core ◽  
Landscape Units ◽  
Civil Engineers

RESUMO As vertentes são os elementos principais da superfície terrestre e é muito importante para geógrafos que se dedicam ao estudo da geomorfologia entendê-las nos seus vários aspectos: formas das vertentes, processos de erosão e intemperismo nelas atuantes. Pode-se definir a vertente como um elemento da superfície terrestre inclinado em relação à horizontal, tendo deste modo um gradiente e uma orientação no espaço. Há vários objetivos no estudo das vertentes. Para o geomorfólogo, elas são unidades da superfície da Terra fundamentais para explicar a evolução do relevo. Os estudos das vertentes não interessam apenas aos geógrafos da disciplina geomorfologia, mas também aos engenheiros, agrônomos e outros profissionais que lidam com agricultura, mineração ou atividades afins. Contudo cada um destes profissionais só se preocupa com um aspecto particular das vertentes. O geomorfólogo é o único que tem uma visão abrangente de todos os aspectos das vertentes.ABSTRACT Hillslopes are the basic elements of all landscapes and is important for the students of geomorphology to appreciate how important they are in all aspects of the discipline. Is fundamental to geomorphology to understand forms and natural processes acting on slope facets which form almost the whole of the earth’s land surface We may define a hillslope as an element of the earth’s surface inclined to the horizontal. Thus a slope processes a gradient and an orientation in space What are the aims of hillslope studies?. To geomorphologists, hillslopes are basic landscape units and so they are fundamental to any explanation of landscape development, thus, simply describe and explain hillslopes evolution. However, hilslope studies have a much wider relevance than landscape explanation alone. Civil engineers involved with construction projects are constantly concerned with hillslope. Road gradients must not exceed acceptable standards, important question of slope stability. Landslides on embankments and cuttings shall be avoided. Agriculture on hillslopes is that mechanization is more difficult and soil erosion by flowing water is more acute, as slopes get steeper. However Engineering and agriculture sciences tend to confine their attention to specific properties of slope types. Geomorphologists are interested in ali kind of slopes, because their studies are the core of geomorphology.

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