scholarly journals The Pressure‐Temperature‐time‐deformation history of the Beni Mzala unit (Upper Sebtides, Rif belt, Morocco): Refining the Alpine tectono‐metamorphic evolution of the Alboran Domain of the Western Mediterranean

2020 ◽  
Author(s):  
Sara Marrone ◽  
Patrick Monié ◽  
Federico Rossetti ◽  
Federico Lucci ◽  
Thomas Theye ◽  
...  
Keyword(s):  
Western Mediterranean ◽  
Deformation History ◽  
Metamorphic Evolution ◽  
Time Deformation ◽  
Rif Belt ◽  
History Of ◽  
Temperature Time

Freeze-etch TEM of aqueous polymer gel network morphology

1986 ◽  
Vol 44 ◽  
pp. 796-797
Author(s):  
J. A. N. Zasadzinski ◽  
R. K. Prud'homme
Keyword(s):  
Metal Ion ◽  
Polymer Network ◽  
Polymer Gels ◽  
Polymer Gel ◽  
Deformation History ◽  
Crosslinked Polymer ◽  
Aqueous Polymer ◽  
History Of ◽  
Gel Network ◽  
Network Morphology

The rheological and mechanical properties of crosslinked polymer gels arise from the structure of the gel network. In turn, the structure of the gel network results from: thermodynamically determined interactions between the polymer chain segments, the interactions of the crosslinking metal ion with the polymer, and the deformation history of the network. Interpretations of mechanical and rheological measurements on polymer gels invariably begin with a conceptual model of,the microstructure of the gel network derived from polymer kinetic theory. In the present work, we use freeze-etch replication TEM to image the polymer network morphology of titanium crosslinked hydroxypropyl guars in an attempt to directly relate macroscopic phenomena with network structure.

Metasedimentary rocks, intrusions and deformation history in the south-east part of the c. 1800 Ma Ketilidian orogen, South Greenland: Project SUPRASYD 1996

1997 ◽  
pp. 60-65
Author(s):  
Adam A. Garde ◽  
Brian Chadwick ◽  
John Grocott ◽  
Cees Swager
Keyword(s):  
Field Work ◽  
Deformation History ◽  
The South ◽  
Present Contribution ◽  
East Part ◽  
Metasedimentary Rocks ◽  
Deformational History ◽  
Base Camp ◽  
History Of ◽  
Geological Map

NOTE: This article was published in a former series of GEUS Bulletin. Please use the original series name when citing this article, for example: Garde, A. A., Chadwick, B., Grocott, J., & Swager, C. (1997). Metasedimentary rocks, intrusions and deformation history in the south-east part of the c. 1800 Ma Ketilidian orogen, South Greenland: Project SUPRASYD 1996. Geology of Greenland Survey Bulletin, 176, 60-65. https://doi.org/10.34194/ggub.v176.5063 _______________ The south-east part of the c. 1800 Ma Ketilidian orogen in South Greenland (Allaart, 1976) is dominated by strongly deformed and variably migmatised metasedimentary rocks known as the ‘Psammite and Pelite Zones’ (Chadwick & Garde, 1996); the sediments were mainly derived from the evolving Julianehåb batholith which dominates the central part of the orogen. The main purpose of the present contribution is to outline the deformational history of the Psammite Zone in the region between Lindenow Fjord and Kangerluluk (Fig. 2), investigated in 1994 and 1996 as part of the SUPRASYD project (Garde & Schønwandt, 1995 and references therein; Chadwick et al., in press). The Lindenow Fjord region has high alpine relief and extensive ice and glacier cover, and the fjords are regularly blocked by sea ice. Early studies of this part of the orogen were by boat reconnaissance (Andrews et al., 1971, 1973); extensive helicopter support in the summers of 1992 and 1994 made access to the inner fjord regions and nunataks possible for the first time.A preliminary geological map covering part of the area between Lindenow Fjord and Kangerluluk was published by Swager et al. (1995). Hamilton et al. (1996) have addressed the timing of sedimentation and deformation in the Psammite Zone by means of precise zircon U-Pb geochronology. However, major problems regarding the correlation of individual deformational events and their relationship with the evolution of the Julianehåb batholith were not resolved until the field work in 1996. The SUPRASYD field party in 1996 (Fig. 1) was based at the telestation of Prins Christian Sund some 50 km south of the working area (Fig. 2). In addition to base camp personnel, helicopter crew and the four authors, the party consisted of five geologists and M.Sc. students studying mafic igneous rocks and their mineralisation in selected areas (Stendal et al., 1997), and a geologist investigating rust zones and areas with known gold anomalies.

scholarly journals Direct dating reveals the early history of opium poppy in western Europe

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Aurélie Salavert ◽  
Antoine Zazzo ◽  
Lucie Martin ◽  
Ferran Antolín ◽  
Caroline Gauthier ◽  
...  
Keyword(s):  
Western Europe ◽  
Western Alps ◽  
Western Mediterranean ◽  
Opium Poppy ◽  
Radiocarbon Dates ◽  
Macrobotanical Remains ◽  
History Of ◽  
Temperate Europe ◽  
Radiocarbon Chronology ◽  
Botanical Remains

AbstractThis paper aims to define the first chrono-cultural framework on the domestication and early diffusion of the opium poppy using small-sized botanical remains from archaeological sites, opening the way to directly date minute short-lived botanical samples. We produced the initial set of radiocarbon dates directly from the opium poppy remains of eleven Neolithic sites (5900–3500 cal BCE) in the central and western Mediterranean, northwestern temperate Europe, and the western Alps. When possible, we also dated the macrobotanical remains originating from the same sediment sample. In total, 22 samples were taken into account, including 12 dates directly obtained from opium poppy remains. The radiocarbon chronology ranges from 5622 to 4050 cal BCE. The results show that opium poppy is present from at least the middle of the sixth millennium in the Mediterranean, where it possibly grew naturally and was cultivated by pioneer Neolithic communities. Its dispersal outside of its native area was early, being found west of the Rhine in 5300–5200 cal BCE. It was introduced to the western Alps around 5000–4800 cal BCE, becoming widespread from the second half of the fifth millennium. This research evidences different rhythms in the introduction of opium poppy in western Europe.

scholarly journals Burial-deformation History of Folded Rocks Unraveled by Fracture Analysis, Stylolite Paleopiezometry and Vein Cement Geochemistry: A Case Study in the Cingoli Anticline (Umbria-Marche, Northern Apennines)

Geosciences ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 135
Author(s):  
Aurélie Labeur ◽  
Nicolas E. Beaudoin ◽  
Olivier Lacombe ◽  
Laurent Emmanuel ◽  
Lorenzo Petracchini ◽  
...  
Keyword(s):  
Isotope Geochemistry ◽  
Central Italy ◽  
Microstructural Analysis ◽  
Northern Apennines ◽  
Foreland Basins ◽  
Deformation History ◽  
The North ◽  
Regional Tectonic ◽  
History Of ◽  
Clumped Isotope

Unravelling the burial-deformation history of sedimentary rocks is prerequisite information to understand the regional tectonic, sedimentary, thermal, and fluid-flow evolution of foreland basins. We use a combination of microstructural analysis, stylolites paleopiezometry, and paleofluid geochemistry to reconstruct the burial-deformation history of the Meso-Cenozoic carbonate sequence of the Cingoli Anticline (Northern Apennines, central Italy). Four major sets of mesostructures were linked to the regional deformation sequence: (i) pre-folding foreland flexure/forebulge; (ii) fold-scale layer-parallel shortening under a N045 σ1; (iii) syn-folding curvature of which the variable trend between the north and the south of the anticline is consistent with the arcuate shape of the anticline; (iv) the late stage of fold tightening. The maximum depth experienced by the strata prior to contraction, up to 1850 m, was quantified by sedimentary stylolite paleopiezometry and projected on the reconstructed burial curve to assess the timing of the contraction. As isotope geochemistry points towards fluid precipitation at thermal equilibrium, the carbonate clumped isotope thermometry (Δ47) considered for each fracture set yields the absolute timing of the development and exhumation of the Cingoli Anticline: layer-parallel shortening occurred from ~6.3 to 5.8 Ma, followed by fold growth that lasted from ~5.8 to 3.9 Ma.

Deformation history of the Paleoproterozoic Liaohe assemblage in the eastern block of the North China Craton

2005 ◽  
Vol 24 (5) ◽  
pp. 659-674 ◽  
Author(s):  
Sanzhong Li ◽  
Guochun Zhao ◽  
Min Sun ◽  
Zongzhu Han ◽  
Yan Luo ◽  
...  
Keyword(s):  
North China Craton ◽  
North China ◽  
Deformation History ◽  
The North ◽  
History Of

Run-on in Gasoline Engines

1968 ◽  
Vol 183 (1) ◽  
pp. 21-51 ◽  
Author(s):  
W. S. Affleck
Keyword(s):  
Combustion Chamber ◽  
Time History ◽  
Spontaneous Ignition ◽  
Research Octane Number ◽  
Gasoline Engines ◽  
Engine Cooling ◽  
History Of ◽  
Valve Overlap ◽  
Temperature Time ◽  
Small Valve

When the ignition of a car engine is switched off, the engine normally comes to rest within a few revolutions but, occasionally, it may continue to fire erratically for a few seconds or longer. This phenomenon is known as run-on and, for the majority of European engines, is the result of spontaneous ignition of the fuel-air mixture in the combustion chamber. Part 1 of this paper describes experiments in a single-cylinder research engine which have been made to establish the principles controlling run-on. In particular the effects of air/fuel ratio, the nature of the fuel and the pressure-temperature-time history of the fuel-air mixture in the combustion chamber have been studied, as it is known that these factors play an important part in spontaneous ignition in experiments in laboratory vessels. From these observations it has been possible to formulate a theoretical model of the run-on process which explains the salient features of the phenomenon. In particular, it shows how the gradual cooling of the engine limits the duration of run-on and also how the duration of run-on may be considered as a measure of the extent to which fuel or engine factors must be altered to eliminate run-on. Part 2 describes the application of these principles to car engines using normal commercial-type fuels. It is concluded that the following are important features in the control of run-on: the use of fuel of sufficiently high Research octane number, minimum opening of throttle at idle, sufficient time for cooling of the combustion chamber before the ignition is switched off, efficient engine cooling, and small valve overlap. Current devices for reducing exhaust emissions are likely, through their effects on these features, to increase the tendency of an engine run-on. Combustion chamber deposits, though, appear to have little influence.

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