Search results for "Tectonic"

Geophysical investigations along the Tyrrhenian shore of Calabria

2016

The Tyrrhenian Sea is a widely investigated basin developed in the Mediterranean area within the frame of Europe- Africa convergence and Ionian plate subduction process (Faccenna et al., 2014; Orecchio et al., 2014 and references therein). Since the Late Miocene, extension within the Tyrrhenian Sea was associated with coeval shortening in the Apennines-Maghrebide orogen and progressive southeastward rollback of the Ionian subducting plate. In this framework both extension and widespread volcanism well represented by the Vavilov and Marsili basins and the Aeolian volcanic arc, are typical features of the Tyrrhenian Sea region. Several authors (De Ritis et al., 2010; Loreto et al., 2015 and r…

Comment and Reply on "Age and tectonic setting of Late Archean greenstone-gneiss terrain in Henan Province, China, as revealed by single-grain zircon…

1988

Archaean Crystalline Rocks of the Eastern Kaapvaal Craton

2019

The eastern part of the Kaapvaal Craton represents a classical granitoid-greenstone terrain and contains the oldest rocks of the African continent, exhibiting about 1000 Ma of crustal evolution from 3.66 to 2.67 Ga. The granitoid rocks predominantly consist of the tonalite–trondhjemite–granodiorite (TTG) association with true granites becoming abundant at about 3 Ga. Greenstones are represented by the well-preserved and well-studied 3.54–3.2 Ga Barberton Greenstone Belt and smaller ca. 3.45 Ga greenstone belt remnants infolded in TTG gneisses around the BGB as well as in the Ancient Gneiss Complex in Swaziland. The origin of both the TTGs and greenstone units is still debated as strong defo…

Significance of earthquake-related anomalies in fluids of Val D'Agri (southern Italy)

2001

Geochemical investigations carried out at the Campano–Lucano Apennine (Southern Italy) revealed the presence of fluids composed of a mixing between components of shallow and deep origin, where mantle-derived helium is also detectable. For the gas phase, the deep component is represented by both CH4 and CO2-rich gases, while the shallow one is N2-dominated. Coinciding with the 3 April 1996 ML=4.9 earthquake, the CH4-rich component mixed with the shallow, N2-dominated one at the Tramutola well (Val d’Agri), displaying wide variations in mixing proportions. In contrast, no significant modifications occurred in relation to the 1998 ML=5.5 event. According to the collected data, an earthquake-re…

DISCUSSION ON THE RELATIONSHIP BETWEEN DEEP SEISMIC REFLECTION PATTERNS AND TECTONIC UNITS OF THE EASTERN PART OF THE CENTRAL ASIAN OROGENIC BELT IN …

2017

Division of tectonic units in the eastern part of the Central Asian Orogenic Belt in northeast China has been a major concern and resulted in much fieldwork, but the division of these tectonic units in NE China is still controversial. Although detection of tectonic units in seismic sections is not straightforward, for this meeting, we shall try to relate tectonic units with the crustal and upper mantle structure and deformation derived from a ~2500 km long reflection seismic profile (Figure, red lines) in this area, recently acquired or reprocessed with support of China Geological Survey and the Chinese SinoProbe Project.

Successes and failures in geodynamics

2001

Abstract The evolution of Earth models is reviewed and the open questions and problems are highlighted. Generally, evolution of science was not linear, but proceeded in “steps” of paradigms; where old ones remained within useful limits. “Geodynamic hypotheses”, while embedded into the general concepts of space and time, were often mutually exclusive and competing until the 1900s. Wegener's concept of continental drift was the first successful globally unifying view, but it was discarded by most Earth scientists. The “real” change of paradigms did not come before mid-century through geophysical observations in paleomagnetism, seismology, bathymetry, seafloor geology and dating, leading to th…

Erratum to “First description of a metamorphic sole related to ophiolite obduction in the northern Caribbean: Geochemistry and petrology of the Güira…

2014

Porphyroblasts and Reaction Rims

1998

A volume of rock involved in deformation and metamorphism will continuously undergo changes in structure and mineral content. This chapter treats mineral growth and replacement structures and the way in which their geometry can be used to reconstruct tectonic history. Two types of informative structures are treated: porphyroblasts and reaction rims.

Mechanisms of fluid flow and fluid-rock interaction in fossil metamorphic hydrothermal systems inferred from vein-wallrock patterns, geometry and mic…

2001

Comparison of mass transfer patterns, geometry and microstructures developed within and around veins allows the interpretation of processes of fluid flow during deformation, metamorphism and mineralization. A classification of vein types based on the degree of interaction with wallrock (using petrological, geochemical or isotopic indicators) can be used to identify a range of processes, from closed system behaviour in which the vein mass is derived from local wallrock, through to open system behaviour in which the vein mass is derived externally. Microstructural characteristics, such as wallrock selvages, multiple growth events recorded by vein seams and vein crystal morphology, also help t…

3D visualization of sheath folds in Ancient Roman marble wall coverings from Ephesos, Turkey

2014

Abstract Archaeological excavations and restoration of a palatial Roman housing complex in Ephesos, Turkey yielded 40 wall-decorating plates of folded mylonitic marble (Cipollino verde), derived from the internal Hellenides near Karystos, Greece. Cipollino verde was commonly used for decoration purposes in Roman buildings. The plates were serial-sectioned from a single quarried block of 1,25 m3 and provided a research opportunity for detailed reconstruction of the 3D geometry of meterscale folds in mylonitized marble. A GOCAD model is used to visualize the internal fold structures of the marble, comprising curtain folds and multilayered sheath folds. The sheath folds are unusual in that the…