This research studies 6 eclogites from Qinglongshan Donghai in the Sulu ultrahigh-pressure (UHP) province, eastern China. Petrographic microscope, Ramam spectrometer, scanning electron microscope (SEM) and transmission electron microscope (TEM) are utilized to identify mineral compositions, microstructures and mineral precipitates. Optical observations show the eclogites with the following mineral assemblage: garnet + omphacite + amphibole + epidote + rutile ¡Ó quartz ¡Ó phengite ¡Ó kyanite ¡Ó coesite pseudomorph ¡Ó apatite ¡Ó talc. Oriented mineral precipitates are found within omphacite and within apatites. The parallel precipitates in omphacite are quartz rods confirmed by electron probe microanalysis (EPMA) and TEM diffraction patterns. The direction of the long axes of the quartz rods seem to have relation with the cleavage and with the parting of omphacite. The direction of the long axis of quartz is not necessarily the c axis direction of quartz. Pargasite is intergrown with quartz and the amounts of both minerals seem to have a positive relation. Pargasite contain element K which is not found in omphacite and there is no obvious crystallographic relation between quartz, pargasite, and omphacite. There is amphibole exsolved from the omphacite and the crystallographic axes of tht exsolved amphibole parallel to those of omphacite. The a and c parameters for the two phases are equal while the b parameter of the amphibole is almost twice that of omphacite. A two-stage growth mechanism for quartz and amphibole intergrown within omphacite is proposed: (1) very fine quartz rods exsolved (or aided with infilling fluids) from a supersilicic clinopyroxene during decompression, creating grain boundaries between quartz rods and host, (2) growth of amphibole and quartz along the grain boundaries with fluid participation and an expense of omphacite during retrograde metamorphism. There are two different precipitates within apatites in different eclogites. One of the precipitates is calcium sulfate (anhydrite or gypsum) and the other is ferrous sulfide (pyrrhotite?). There was no report about calcium sulfate within apatite in UHP rocks before. The formation of sulfide (reduced) or sulfate (oxidized) is controlled by the fugacity of oxygen. According to the previous reports and the discoveries of this research, there are many different kinds of precipitates containing silicate incompatible elements in apatites. It can¡¦t be ruled out that the precipitates exsolved from apapites but apatites are more likely to act as sinks of silicate incompatible elements and different minerals precipitated within apatites under different redox conditions rather than exsolution processes.

The fabrication characteristic of focused ion beam (FIB) for fused quartz was investigated. With the progress of nanotechnology, new technologies and devices are invented constantly. In nanofabrication, FIB has several advantages such as high material removal rate, high resolving power and direct fabrication in some selected areas without etching mask. Therefore, it had been studied in detail to fabricate nano-structures by FIB. In this study, we found out the effect of nano-machining by adjusting the parameters of FIB system such as: beam current, overlap, and dwell time. The fabricated features together with their surface morphology and profile were investigated by scanning electron microscope (SEM) and atomic force microscope (AFM). Results show that when beam current was smaller, overlap was 50% and dwell time was 10£gs could get best performance by FIB.

No description available.

Quarries are fixed locationally, whereas most seasonally abundant food resources in northern latitudes are not. Toolstone procurement must therefore be ‘factored in’ to other resource procurement strategies. As sources of useable toolstone, quarries are the logical starting point for the study of how stone tool-using societies organized their technologies in accordance with their subsistence and social needs. Yet they have often been ignored by archaeologists because of the logistical problems presented by their typically enormous and variable assemblages. Quartz differs from more common, crypto-crystalline raw materials such as chert, flint or chalcedony. It is harder, more brittle, and has different fracture properties. It is less common archaeologically than crypto-crystalline toolstone, and archaeologists tend to either avoid quartz assemblages altogether, or to automatically and uncritically analyze them in the same manner as crypto-crystalline toolstones without considering their different properties. The Grandfather Quarry (HbMd-4) offers an opportunity to address these problems at once. Using Lithic Technological Organization theory, a mass analysis (after Ahler 1989), modified and combined with an attribute analysis, demonstrates that this method is a useful tool for examining large, complex assemblages such as those found in quarry sites. While more time-consuming and labour-intensive than a standard mass analysis, the modified version allows for the collection of a large number of attribute data that lend robusticity to the results and provide academic rigour. This research also demonstrates that quartz assemblages can indeed be examined using the same methods as for other raw materials, provided the unique properties of quartz as a toolstone are considered. It is shown that although the overall quality of toolstone from this source is quite poor, the Grandfather Quarry was likely the only reliable source, or at least one of a very few reliable sources, of quartz toolstone in the Churchill River Basin. All useable toolstone was intensively exploited, but rare nodules of higher quality quartz were set aside for in situ reduction into cores, tools and bifaces. Lastly, the unexpected discovery of microblade technology at the quarry opens new avenues for future research in the northern Manitoba Boreal Forest.

Although a large number of works on nanoimprint lithography (NIL) techniques have been reported, the the ability for three-dimensional (3-D) patterning using NIL has not been fully addressed in terms of the mold fabrication and imprint processes. Patterning 3-D and multilevel features are important because they eliminate multiple steps and complex interlevel alignments in the nanofabrication process. The 3-D and multilevel mold design and fabrication, and imprint processes have been studied and investigated in this research work. In the UV-NIL technique, a transparent mold with micro/nanostructure patterns on its surface is allowed to be replicated on UV curable polymer without the need of high applied pressure or temperature. UV-NIL has the potential to fabricate micro/nanostructures with high resolution, high reproducibility, low cost, high throughput and is capable of 3-D patterning. This research focuses on two aspects; the development of mold making and imprint processes. In the process of making a master mold, an EBL technique was employed for writing patterns on e-beam resists. PMMA positive resist was used for 2-D patterning and ma-N2403 negative resist from Microresist Technology was used for 3-D patterning. After being developed, the 3-D mold pattern was transferred onto quartz substrate using a single-step reactive ion etching (RIE) technique. A number of challenging issues such as surface charging, electron scattering and proximity effects surfaced during the EBL pattern writing on insulating and transparent molds. A number of new approaches have been developed for suppressing the charging effects in the 2-D and 3-D patterning. Using thin metallic coating on the quartz substrates or on top of the resist, or conductive polymer coating using PEDOT/PSS on top of the resist has demonstrated excellent results in a 2-D structure with a high aspect-ratio of 1:10 and feature sizes down to 60 nm. In 3-D patterning, two approaches have been followed; the critical energy method and/or a top coating of conductive polymer (PEDOT/PSS) layer. Isolated 3-D structures with feature sizes down to 500 nm were successfully fabricated using the first method while by using the second method, dense 3-D structures patterns with feature sizes down to 300 nm, on 400 nm pitch have been demonstrated. In UV-NIL, the surface roughness Rq(rms) should be less than 5 nm, which is important for replicating optical structures and devices. In this work, the RIE process been optimized to yield 2 nm roughness on a patterned quartz surface. This was achieved by optimizing the RIE process pressure of below 6 mTorr. The other part of this thesis is on replication or imprinting of 2-D and 3-D structures. In the process of replicating the master mold profiles, the imprint processes were carried out using a vacuum operated manual imprint tool which was attached to a Mask Aligner UV illumination system. In 2-D imprinting, resist sticking on the vertical side wall was the main issue, especially on high aspect ratio structures. Meanwhile in 3-D imprinting, the imprint results have shown good reproducibility in up to 15 imprint cycles, where the issue of Ormocomp soft/daughter mold cracking after long UV exposure had limited the repetition of the imprint cycles. In this thesis, the 2-D and 3-D resist patterning on insulating substrates using the EBL technique have been demonstrated with the assistance of a number of developed charge suppression methods. Single-step RIE pattern transfer onto quartz substrates with surface roughness below 5nm has been achieved. Replication of 3-D and multilevel structures reliably make the UV-NIL technique suitable for future applications such as surface texturing, optical devices and many other complex structures including MEMS.

Quarries are fixed locationally, whereas most seasonally abundant food resources in northern latitudes are not. Toolstone procurement must therefore be ‘factored in’ to other resource procurement strategies. As sources of useable toolstone, quarries are the logical starting point for the study of how stone tool-using societies organized their technologies in accordance with their subsistence and social needs. Yet they have often been ignored by archaeologists because of the logistical problems presented by their typically enormous and variable assemblages. Quartz differs from more common, crypto-crystalline raw materials such as chert, flint or chalcedony. It is harder, more brittle, and has different fracture properties. It is less common archaeologically than crypto-crystalline toolstone, and archaeologists tend to either avoid quartz assemblages altogether, or to automatically and uncritically analyze them in the same manner as crypto-crystalline toolstones without considering their different properties. The Grandfather Quarry (HbMd-4) offers an opportunity to address these problems at once. Using Lithic Technological Organization theory, a mass analysis (after Ahler 1989), modified and combined with an attribute analysis, demonstrates that this method is a useful tool for examining large, complex assemblages such as those found in quarry sites. While more time-consuming and labour-intensive than a standard mass analysis, the modified version allows for the collection of a large number of attribute data that lend robusticity to the results and provide academic rigour. This research also demonstrates that quartz assemblages can indeed be examined using the same methods as for other raw materials, provided the unique properties of quartz as a toolstone are considered. It is shown that although the overall quality of toolstone from this source is quite poor, the Grandfather Quarry was likely the only reliable source, or at least one of a very few reliable sources, of quartz toolstone in the Churchill River Basin. All useable toolstone was intensively exploited, but rare nodules of higher quality quartz were set aside for in situ reduction into cores, tools and bifaces. Lastly, the unexpected discovery of microblade technology at the quarry opens new avenues for future research in the northern Manitoba Boreal Forest.

No description available.

Hydrothermal fluid flow is spatially and genetically associated with deformation in the earth�s crust. In the Otago Schist, New Zealand, the circulation of hydrothermal fluids in the Cretaceous formed numerous mesothermal gold-quartz vein deposits. Otago schist rocks are largely L-S tectonites in which the penetrative fabric is the product of more than one deformation phase/transposition cycle. Regional correlation of deformation events allowed mineralised deposits to be related to the structural evolution of the Otago Schist. Compilation of a detailed tectonostratigraphy of New Zealand basement rocks reveals that extensional mineralisation correlates with the onset of localised terrestrial fanglomerate deposition, thermal perturbation and granitic intrusion that mark the beginning of New Zealand rifting from the Antarctic portion of Gondwana. Laminated and breccia textures in mineralised veins suggest that host structures have experienced repeated episodes of incremental slip and hydrothermal fluid flow. However, analysis of vein orientation data in terms of fault reactivation theory (Amontons Law) shows that most deposits contain veins that are unfavourably oriented for frictional reactivation. Repeated movement on unfavourably oriented structures may involve dynamic processes of strain refraction due to competency contrasts, the effect of anisotropy in the schist, or localised stress field rotation. Deposits have been classified on the basis of host structure kinematics at the time of mineralisation into low angle thrust faults, and high angle extensional fault - fracture arrays. Low angle deposits have a mapped internal geometry that is very different from conventional imbricate thrust systems. This study applied ⁴⁰Ar/�⁹Ar geochronology to selected deposits and has identified at least three distinct mineralisation events have occurred within the central axial belt during the Cretaceous. Relationships between radiometric apparent age and inferred crustal depth reveal that after metamorphism, the onset of cooling and rapid exhumation of the schist belt coincides temporally and spatially with the age of mineralisation and structural position of a regional scale low angle shear zone in Otago.

The search for a reliable and non-invasive technique for the dating of rock art has produced an array of different, localised, and limited techniques. This is one of them. Still in its experimental stage, the recognition of quartz microdebitage produced by the pecking of engravings is the aim of this project. This investigation aims to establish whether microdebitage from rock engravings can be distinguished from other sediments. Analysis of microdebitage from rock engraving experiments was used to determine the difference between experimental and naturally derived particles. This research discusses methodology, and applications for the recognition of quartz grain features, derived from experimental and natural material from Mutawintji National Park (Broken Hill, NSW, Australia) and the Sydney region (NSW Australia). A three-step process was devised for this research: What features occur on non-cultural quartz grains? What features occur on rock engraving quartz grains? Are they different? Can rock engraving quartz microdebitage be identified under natural conditions? Microdebitage from rock engravings was examined using optical and scanning electron microscopy to identify diagnostic attributes, with the objective of assessing the potential of microdebitage for spatial and temporal archaeological investigation. Characteristics of the quartz grains in the microdebitage were compared with quartz from differing environments. The observation of diagnostic features on quartz grains made it possible to discriminate between microdebitage from rock engravings and the natural soil background. This knowledge may be applied to excavated material from archaeological sites, for identifying episodes of rock engraving and other lithic activity in temporal relation to other evidence of cultural activity.

Thesis (Ph.D.)--University of Nebraska-Lincoln, 2007. / Title from title screen (site viewed Dec. 4, 2007). PDF text: xii, 80 p. : ill. ; 6 Mb. UMI publication number: AAT 3273191. Includes bibliographical references. Also available in microfilm and microfiche formats.