Looking for a Definition of Neotectonics

Pavlides, Spyros

doi:10.1111/j.1365-3121.1989.tb00362.x

Cited by 25 publications

(16 citation statements)

References 6 publications

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“…6, N.1, p. 75-110, 2016 ISSN 2237-3071 tectônicos. Já Pavlides (1989) afirma que neotectônica está ligada a eventos tectônicos novos, que ocorreram ou estão ocorrendo numa região após a orogênese final ou, mais precisamente, após a sua reorganização tectônica mais significativa, e Hasui (1990) define que eventos neotectônicos estão diretamente relacionados à tectônica ressurgente, definida como uma manifestação tectônica intermitente de falhas em episódios separados por intervalos de quiescência. Este autor afirma ainda que durante a atuação de um regime de esforços, dependendo da orientação da falha preexistente em relação aos esforços e a intensidade destes, é mais fácil reativar uma falha preexistente do que nuclear uma nova falha.…”

Section: Neotectônicaunclassified

Procedimentos Metodológicos e Técnicas em Geomorfologia Tectônica

Bricalli

2016

EspacoAberto

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Há uma notória relação entre Neotectônica e aspectos da morfologia das paisagens atuais. Nos últimos anos, a tectônica envolvendo o intervalo de tempo do Neógeno e do Quaternário (Neotectônica) tem sido amplamente investigada para explicar as feições morfotectônicas, especialmente na região Sudeste e Nordeste do Brasil. A base metodológica utilizada para estudos em Geomorfologia Tectônica deve integrar: análise de domínios de lineamentos sobre MDE, pois podem indicar reativação de linhas de fraqueza pré-cambrianas; análise estrutural de conjuntos de pares falha/estria afetando o embasamento alterado e os depósitos neogênicos, que podem apontar eventos tectônicos geradores de estruturas e do relevo; análises morfotectônicas que correspondem a formas sob o controle tectônico ativo, resultado de movimentos crustais ocorridos no cenozoico; análises hipsométricas que podem indicar blocos altos e baixos com origem tectônica; análise da rede de drenagem, através da identificação de anomalias de drenagem, cálculo de assimetria de drenagem, identificação de padrões de drenagem controlados tectonicamente, orientação da rede de drenagem e identificação de knickpoints. A preocupação central desse artigo é demonstrar que não se realiza pesquisa em Geomorfologia Tectônica dissociada da Neotectônica, uma vez que feições derivadas de ação tectônica antiga apresentam variação de suas características devido a processos erosivos.

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Section: Neotectônicaunclassified

Procedimentos Metodológicos e Técnicas em Geomorfologia Tectônica

Bricalli

2016

EspacoAberto

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“…The idea of a rapid mountain building period has been an accepted idea in Russia for quite a while. Pavlides (1989) first brought the idea to western notice, and he attributes it to Obruchev (1948) which we have not seen. The mountain building period is known as the Neotectonic Period, and was defined by Obruchev as 'Young tectonic movements occurring in the late Tertiary and early half of the Quaternary'.…”

Section: Introductionmentioning

confidence: 97%

Neotectonic mountain uplift and geomorphology

Ollier

Pain

2019

Geomorphology RAS

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Mountains are topographic features caused by erosion after vertical uplift or mountain building. Mountain building is often confused with orogeny, which today means the formation of structures in fold belts. The common assumption that folding and mountain building go together is generally untrue. Many mountains occur in unfolded rocks, granites and volcanic rocks, so there is no direct association of folding and mountain building. In those places where mountains are underlain by folded rocks the folding pre-dates planation and uplift. The age of mountains is therefore not the age of the last folding (if any) but the age of vertical uplift. Since mountains are not restricted to folded rocks, lateral compression is not required to explain the uplift. A compilation of times of uplift of mountains around the world shows that a major phase of tectonic uplift started about 6 Ma, and much uplift occurred in the last 2 Ma. This period is known as the Neotectonic Period. It is a global phenomenon including mountains on passive continental margins, and those in deep continental interiors. Several hypotheses of mountain building have problems with this timing. Some fail by being only able to make mountains out of folded rock at continental margins. Many translate the vertical uplift into lateral compression, but vertical uplift alone can create mountains. The Neotectonic Period has important implications for geomorphology, climate and global tectonics. In geomorphology it does not fit into conventional theories of geomorphology such as Davisian or King cycles of erosion. Neotectonic uplift might initiate several cycles of erosion, but most planation surfaces are much older than the Neotectonic Period. The increasing relief associated with Neotectonic uplift affected rates of erosion and sedimentation, and also late Cenozoic climate. The Neotectonic Period does not fit within plate tectonics theory, in which mountains are explained as a result of compression at active margins: mountains in other locations are said to have been caused by the same process but further back in time. This is disproved by the young age of uplift of mountains in intercontinental and passive margin positions. Subduction is supposed to have been continuous for hundreds of millions of years, so fails to explain the world-wide uplifts in just a few million years. Geomorphologists should be guided by their own findings, and refrain from theory-driven hypotheses of plate collision or landscape evolution.

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“…Such faults are controlled by contemporary tectonics, or "Neotectonics" (e.g., Mw 6.2, Aysén, 2007, Vargas et al, 2013 or are produced by the reactivation of inherited mechanical anisotropies under a different setting (Paleotectonics) with respect to the present-day stress-field (e.g., Mw 6.9 and Mw 7.0, Pichilemu, 2010, Aron et al, 2013). The term Neotectonics, which has been used variably by previous authors (Mercier, 1976.;Fairbridge, 1981;Hancock and Williams, 1986;Vita-Finzi, 1987;Hancock, 1988;Pavlides, 1989;Mörner, 1994;Costa et al, 2006a), here refers to the study of the processes and structures acting since the contemporary stress field of a given region was established (Stewart y Hancock, 1994). In Chile, this refers to the tectonic system which has been active since at least the start of the Pliocene (González et al, 2003;Cembrano et al, 2007;Ramos 2009a).…”

Section: Introductionmentioning

confidence: 99%

Crustal faults in the Chilean Andes: geological constraints and seismic potential

Santibanez

Cembrano

García-Pérez

et al. 2018

andgeo

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The Chilean Andes, as a characteristic tectonic and geomorphological region, is a perfect location to unravel the geologic nature of seismic hazards. The Chilean segment of the Nazca-South American subduction zone has experienced mega-earthquakes with Moment Magnitudes (Mw) >8.5 (e.g., Mw 9.5 Valdivia, 1960; Mw 8.8 Maule, 2010) and many large earthquakes with Mw >7.5, both with recurrence times of tens to hundreds of years. By contrast, crustal faults within the overriding South American plate commonly have longer recurrence times (thousands of years) and are known to produce earthquakes with maximum Mw of 7.0 to 7.5. Subduction-type earthquakes are considered the principal seismic hazard in Chile, with the potential to cause significant damage to its population and economy. However crustal (non-subduction) earthquakes can also cause great destruction at a local scale, because of their shallower hypocentral depth. Nevertheless, the nature, timing and slip rates of crustal seismic sources in the Chilean Andes remain poorly constrained. This work aims to address the seismic potential of the crustal faults in Chile, contributing to the estimation of key fault parameters for the seismic hazard assessment. We have examined the main parameters involved in the magnitude of an earthquake, including length, width and mean displacement of some case studies crustal faults and their morphotectonic settings, exposing the parametrical similarities in longitudinal domains (N-S stripes) and disparity from W to E, across latitudinal domains. The maximum hypocentral depths for crustal earthquakes vary across margin parallel tectonic domains aligned parallel, from 25-30 km in the outer forearc to 8-12 km in the volcanic arc, thus allowing for a first-order approach for seismic potential assessment. Current structural, paleoseismological and geodetic data, although sparse and limited, suggest that slip rates of Chilean crustal faults range from 0.2 mm/yr (in the forearc region) to up to 7.0 mm/yr (in the intra-arc region). The different tectonic modes for crustal fault reactivation and their wide range of slip rates complicates the estimation of seismic hazard. A rigorous seismic hazard assessment must therefore consider the different tectonic settings, timing and slip rates of Andean crustal faults. Understanding the nature of these faults will allow a better evaluation of the associated seismic hazard, and better constraints to be placed on their relationship with the subduction seismic cycle.

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Looking for a Definition of Neotectonics

Cited by 25 publications

References 6 publications

Procedimentos Metodológicos e Técnicas em Geomorfologia Tectônica

Procedimentos Metodológicos e Técnicas em Geomorfologia Tectônica

Neotectonic mountain uplift and geomorphology

Crustal faults in the Chilean Andes: geological constraints and seismic potential

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