Search results for " ROC"

Origin and Evolution of High-Grade Gneiss Terrains

1990

In the previous chapters we have given an impression of the way in which the analysis of high-grade rocks can be approached in the field. Here we conclude with some current larger-scale ideas on the origin and evolution of such rock assemblages.

Space-borne frequency comb metrology

2016

Precision time references in space are of major importance to satellite-based fundamental science, global satellite navigation, earth observation, and satellite formation flying. Here we report on the operation of a compact, rugged, and automated optical frequency comb setup on a sounding rocket in space under microgravity. The experiment compared two clocks, one based on the optical D2 transition in Rb, and another on hyperfine splitting in Cs. This represents the first frequency comb based optical clock operation in space, which is an important milestone for future satellite-based precision metrology. Based on the approach demonstrated here, future space-based precision metrology can be i…

Assessment of soil particle erodibility and sediment trapping using check dams in small semi-arid catchments

2017

Check dams can be used as a source of information for studies on sediment characteristics and soil particle erodibility. In this study, sediment yield and grain size distribution (GSD) were measured in twenty small catchments draining into a rock check dam in NW Iran for different runoffs during 2010–2011. Significant correlations were found between sediment yield and slope steepness, vegetation cover and soil erodibility factor (K) of the catchments. The erodibility of soil particles was determined using the comparison of GSD between sediment and original soil. Clay was the most erodible soil particle which showed 2.05 times more percentage in sediment than the original soil. The erodibili…

Towards a dendrochronologically refined date of the Laacher See eruption around 13,000 years ago

2020

Highlights • Previous age estimates of the Laacher See Eruptions (LSE) around 12,900 years are still diverging and imprecise. • The combination of dendrochronology, wood anatomy, and 14C measurements holds the potential to establish a precise LSE date. • An absolute calendric date of the LSE would improve the synchronization of European Late Glacial to Holocene archives. Abstract The precise date of the Laacher See eruption (LSE), central Europe’s largest Late Pleistocene volcanic event that occurred around 13,000 years ago, is still unknown. Here, we outline the potential of combined high-resolution dendrochronological, wood anatomical and radiocarbon (14C) measurements, to refine the age …

On thrusting, regional unconformities and exhumation of high-grade greenstones in Neoarchean orogens. The case of the Waroonga Shear Zone, Yilgarn Cr…

2017

Abstract During the Neoarchean, the dominant tectonic style progressively changed from an episodic-overturn/stagnant-lid regime to modern-style plate tectonics. The Neoarchean strengthening of continental lithosphere changed the style of deformation of orogenic belts. The case study presented here provides insights into how such transition in tectonic style occurred, a matter that is generally controversial. We present structural and metamorphic data from the c. 2660 Ma Waroonga Shear Zone (WSZ) in the Neoarchean Yilgarn orogen (Western Australia). The WSZ contains a syntectonic pluton and older, high-grade greenstones. The tectonic fabric in the pluton developed during melt-present thrusti…

Vegetation of solid rock faces and fissures of the alpine and subnival zone in the Pamir Alai Mountains (Tajikistan, Middle Asia)

2014

The paper presents results of phytosociological researches on rock faces vegetation of Pamir Alai Mountains. In total, 182 phytosociological relevés were made during the field studies conducted in 2006–2012, applaying the Braun-Blanquet method. Plant communities of calcareous firm rock faces and small fissures, inhabiting mainly the alpine and subnival zone in several ranges (e.g. Zeravshan Mts, Hissar Mts, Hazratishoh Mts, Darvaz Mts, Rushan Mts and Vanch Mts) are herein described for the first time. A hierarchical syntaxonomic synopsis of the rock communities of the Pamir Alai is provided. The collected vegetation samples represent the majority of the variability among the phytocoenoses o…

Taphonomy of the vertebrate bone beds from the Klūnas fossil site, Upper Devonian Tērvete Formation of Latvia

2012

Combined sedimentological and taphonomical study of the siliciclastic sequence of the Tērvete Formation in the stratotypical area was aimed at revealing the formation of the three oryctocoenoses discovered and related structural and textural features of the deposits, as well as at detailed observation of the taphonomical peculiarities of the obtained palaeontological material. The fossil vertebrate assemblage is represented by 14 taxa comprising placoderms, acanthodians, sarcopterygians and actinopterygians. The three oryctocoenoses, first recognized in 2010, differ in the proportions of repeatedly buried material, in the number and degree of preservation of small and fragile skeletal eleme…

Hieracium hypochoeroidessubsp.peracutisquamum(Asteraceae), a New Taxon from Basilicata, Southern Italy

2015

Hieracium hypochoeroides subsp. peracutisquamum Di Grist., Gottschl. & Raimondo, a new taxon endemic to Basilicata (southern Italy), is described and illustrated. It is confined to the carbonate rocks of Monte della Madonna di Viggiano (Lucanian Apennine, SW Basilicata). Information on its habitat ecology and taxonomic relationships is provided.

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

2014

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…