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The Effect of Dietary Adaption on Cranial Morphological Integration in Capuchins (Order. 27 Jun 2014: The PLOS ONE Staff (2014) Correction: The Effect of Dietary Adaption on Cranial Morphological Integration in Capuchins (Order Primates. Finished models were created using the ScanStudio HD software by placing virtual beads on. The HD Pro ScanStudio and Scantools software specific to the 3D scanners, other software for manipulating 3D images includes Av izo, Rhinoceros, SolidWorks, and Rapidform. All 3D scanners are used in the DIVA lab, but we also take a NextEngine scanner to Belize to image fragile and salt-waterlogged artifacts and wooden posts.
Item Metadata Title Porosity-viscosity relationships during compaction of pumice Creator Date Issued 2013-03 Description During compaction of pyroclastic material, strain is mainly accommodated by volume reduction from the closing of pore space. At temperatures above the materials softening point, this deformation is achieved through viscous relaxation.
The effective viscosity of the material increases with loss of porosity and increased viscosity can lead to brittle deformation. Here, high temperature experiments are conducted on pumice cores of diameter 4 cm and length 8 cm, sampled from Mount Meager’s Pebble Creek Formation using the Volcanic Deformation Rig in the Centre for Experimental Study of the Lithosphere (CESL) at the University of British Columbia. Cores were deformed at 875 °C under a constant displacement rate of 2.78.10-⁴ or at constant loads of 1334 N and 3559 N.
Initial and final porosities were measured for each core. The acoustic emissions of brittle deformation were measured with an Acoustic Emission System (PCI-2 AE) where high acoustics indicated fracturing from brittle deformation. Samples showed a strain dependent rheology where the effective viscosity (ηe) increased with increased strain and reduced porosity until viscous deformation was replaced by viscous and brittle deformation. Results show that at this point of viscous-brittle deformation, the stress required to continue straining the material at the same rate increases exponentially. With a constant applied stress, the strain rate will rapidly decrease across this point.
At 875 °C Log10(ηe) increases linearly with porosity loss to a point of zero porosity between 10¹¹˙⁵ to 10¹⁴˙⁵ Pa s. This relationship is important in the welding of ignimbrites and for volcanic recharge, as pyroclastic material can seal a volcanic conduit. The porosity will affect the materials permeability, which will dictate its ability to either effusively release gases or build up pressure leading to an explosive eruption. Type Language eng Series University of British Columbia. EOSC 449 Date Available 2013-11-14 Provider Vancouver: University of British Columbia Library Rights Attribution-NonCommercial-NoDerivatives 4.0 International DOI 10.14288/1.0053614 URI Affiliation Citation Gainer, Daniel. Porosity-Viscosity Relationships During Compaction of Pumice. Undergraduate Honours Thesis.
Department of Earth and Ocean Sciences. University of British Columbia.
Peer Review Status Unreviewed Scholarly Level Undergraduate Copyright Holder Gainer, Daniel Rights URI AggregatedSourceRepository DSpace Download Media 1.59MB Metadata JSON: JSON-LD: RDF/XML (Pretty): RDF/JSON: Turtle: N-Triples: Original Record: Full Text Citation Full Text. I POROSITY-VISCOSITY RELATIONSHIPS DURING COMPACTION OF PUMICE by DANIEL GAINER A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF BACHELOR OF SCIENCE (MAJOR) in THE FACULTY OF SCIENCE (Geology) This thesis conforms to the required standard??????????????? Kelly Russell THE UNIVERSITY OF BRITISH COLUMBIA (Vancouver) MARCH 2013? Daniel Gainer, 2013 ii Abstract During compaction of pyroclastic material, strain is mainly accommodated by volume reduction from the closing of pore space.
At temperatures above the materials softening point, this deformation is achieved through viscous relaxation. The effective viscosity of the material increases with loss of porosity and increased viscosity can lead to brittle deformation. Here, high temperature experiments are conducted on pumice cores of diameter 4 cm and length 8 cm, sampled from Mount Meager?s Pebble Creek Formation using the Volcanic Deformation Rig in the Centre for Experimental Study of the Lithosphere (CESL) at the University of British Columbia.
Cores were deformed at 875?C under a constant displacement rate of 2.78.10-4 or at constant loads of 1334 N and 3559 N. Initial and final porosities were measured for each core. The acoustic emissions of brittle deformation were measured with an Acoustic Emission System (PCI-2 AE) where high acoustics indicated fracturing from brittle deformation.
Samples showed a strain dependent rheology where the effective viscosity (?e) increased with increased strain and reduced porosity until viscous deformation was replaced by viscous and brittle deformation. Results show that at this point of viscous-brittle deformation, the stress required to continue straining the material at the same rate increases exponentially. With a constant applied stress, the strain rate will rapidly decrease across this point. At 875?C Log10(?e) increases linearly with porosity loss to a point of zero porosity between 1011.5 to 1014.5 Pa s. This relationship is important in the welding of ignimbrites and for volcanic recharge, as pyroclastic material can seal a volcanic conduit. The porosity will affect the materials permeability, which will dictate its ability to either effusively release gases or build up pressure leading to an explosive eruption.
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Iii Table of Contents Cover Page. I Abstract. Ii Table of Contents. Iii List of Figures. V List of Tables. Vi List of Symbols. Vii Acknowledgements.
Viii Chapter 1: Introduction. 1 Chapter 2: Background. 3 2.1 Geological Background: Mount Meager Volcanic Complex. 3 Chapter 3: Materials. 4 3.1 Macroscopic Description. 4 3.2 Pumice Sample Preparation. 4 3.3 Density and Porosity.
6 Chapter 4: Methodology. 8 4.1 Volcanic Deformation Rig (VDR). 8 4.1.1 Experimental Apparatus. 8 4.1.2 Sample Assembly.
8 4.1.3 Furnace Assembly. 9 4.1.4 Data Output. 11 4.2 Acoustic Emissions. 12 4.2.1 Device Assembly. 12 4.2.2 Data Output.
13 4.3 Eliminating the Effect of Bulging. 16 Chapter 5: Experimental Methodology. 19 5.1 Preliminary Testing to Determine Temperature of Experiments. 19 5.2 Constant Displacement Experiments.
22 5.3 Constant Load Experiments. 22 5.4 3-D Scanning.
23 iv Chapter 6: Results. 25 6.1 Data Treatment. 25 6.2 Mechanical Data. 26 6.2.1 Constant Displacement. 26 6.2.2 Constant Load.
28 Chapter 7: Data Analysis. 32 7.1 Rheological Data. 32 7.1.1 Constant Strain Rate. 32 7.1.2 Constant Stress. 34 7.2 Effective Viscosity. 36 7.3 Effective Viscosity and Porosity. 37 Chapter 8: Implications.
39 8.1 Welding of Ignimbrites. 39 8.2 Volcanic Recharge. 39 Chapter 9: Conclusion.
39 References. 41 v List of Figures FIGURE 1. VOLCANIC DEFORMATION RIG SCHEMATIC. FURNACE ASSEMBLY. VDR DATA MONITORING. AE ASSEMBLY.
ACOUSTIC WAVEFORM SCHEMATIC. 15 FIGURE 6: ENERGY OF ACOUSTIC EMISSIONS. ALUMINA JACKET AND PUMICE CORE. TWO CORES DEFORMED TO 30% STRAIN.
SAMPLE CORES OF PUMICE COOKED IN A FURNACE. 20 FIGURE 10.TEMPERATURE DETERMINATION DATA. 21 FIGURE 11. NEXTENGINETM 3-D SCANNER.
23 FIGURE 12. 3-D SCAN DATA OUTPUT. 24 FIGURE 13.
CONSTANT DISPLACEMENT MECHANICAL DATA. 27 FIGURE 14. CONSTANT LOAD MECHANICAL DATA. 29 FIGURE 15.
DEFORMED PUMICE CORES. 30 FIGURE 16. CONSTANT DISPLACEMENT RHEOLOGICAL DATA. 33 FIGURE 17. CONSTANT LOAD EXPERIMENTS RHEOLOGICAL DATA. 35 FIGURE 18. EFFECTIVE VISCOSITY AND STRAIN.
36 FIGURE 19. EFFECTIVE VISCOSITY AND POROSITY. 37 FIGURE 20. CHANGES IN EFFECTIVE VISCOSITY AND POROSITY. 38 vi List of Tables TABLE 1. PHYSICAL MEASUREMENTS OF THREE PUMICE CORES. DENSITY AND POROSITY MEASUREMENTS.
EXPERIMENTAL CONDITIONS. PHYSICAL PROPERTIES OF CORES FOR A) FINAL, B) CHANGE 88888FROM INITIAL TO FINAL.
INITIAL AND FINAL EFFECTIVE VISCOSITIES. 38 vii List of Symbols MMVC Mount Meager Volcanic Complex L Length (cm) VT Total volume (cm3) VI+R Volume of rock and isolated pore space (cm3)?B Bulk density (g/cm3)?R Rock density (g/cm3)?S Skeletal density?T Total porosity?C Connected porosity?I Isolated porosity VDR Volcanic Deformation Rig LVDT Linear variable differential transformer PCI-2 AE Peripheral Component Interconnect-2 Acoustic Emission System AE Acoustic emission? Integral V Voltage (V) Vp Peak signal voltage (?V) T Temperature (?C) Tg Glass transition temperature (?C) Approximately TIN Triangulated irregular network? Stress (MPa)? Pi (number) r Radius (m)?
Strain?l Change in length (cm) l Original length (cm) t Time (s)?t Change in time (s)? Strain rate s-1?e Effective viscosity (Pa s)?0 Initial porosity?f Final porosity viii Acknowledgements I would like to thank Dr.
Kelly Russell for the supervision, guidance and support throughout the thesis process. As well as taking me on as a student and for inspiring me to research volcanic processes with his volcanology course.
Thank you to Stephan Kolzenburg for training me on the Volcanic Deformation Rig and AE, ordering my ceramic jackets, helping me to design an experimental method, troubleshooting with me, and for the guidance and inspiration throughout the experimental process. Also in the lab, I would like to thank Amy Ryan for all of her help and support during my experiments and for her final edits, Michelle Campbell for training me on the Nextengine? 3-D Scanner and for using the Matlab? Code to find the volumes of my cores and James Wells for sampling the pumice, setting up the water line on the VDR, training me on the automated saw, and for the wisdom of his own honors thesis experience. In addition I want give a special thanks to J?rn Unger in the machine shop for manufacturing my ceramic piston and ceramic spacers.
As well as grinding down the pumice cores to appropriate lengths, for his support with using the machinery in the cut room, and for machining parts for the new VDR water line. I would also like to thank the Ronald C. Wells Scholarship Fund for the $500 dollar scholarship and the Department of Earth, Ocean and Atmospheric Science for their financial support, and Mary Lou Bevier who instructed the thesis seminar, providing formatting instructions, edits and support. Thank you also to Darcy Baker for encouraging me to write an honors thesis even though I was only enrolled in the major program.
Finally I would like to thank my parents for their support and encouragement throughout my degree.1 Chapter 1: Introduction All magmas vesiculate at the surface due to the exsolution of volatiles (Walsh and Saar, 2008). This degassing can create highly porous volcanic material. Porosity is linked to permeability, which allows for fluid escape in volcanic conduits and reduces the likelihood that over-pressurization, will cause explosive eruptions. The potential for fluid pressure build up and explosive behavior in a volcanic conduit increases if low porosity material undergoes compaction and welding (Kennedy et al., 2005). Hot fragmental material can sinter and compact in a volcanic conduit on a timescale of hours, and reduce the permeability pathway (Quane et al., 2009). Sintering occurs rapidly at high temperature and can be decoupled from the cooling history.
Therefore, when analyzing compaction, the initially fragmented material can be assumed to be consolidated for the entire cooling process (Quane et al., 2009). Compaction processes also control the welding of pyroclastic density current deposits such as ignimbrites. These deposits are comprised of ash, pumice and lithic fragments with void space both between clasts, and in the pores space of vesicular material (Streck and Grunder, 1995). (2004) modeled this compaction using cores of pyroclastic material and an experimental apparatus to apply an effective stress at temperature. Unconfined cores of highly porous pyroclastic material placed under an effective stress at high temperature undergo shortening.
Previous experiments have shown both that shortening in unconfined cores is mainly accommodated by loss of porosity (with minimal bulging), and that the effective viscosity of the material at high temperatures increases with a loss of porosity (Quane et al., 2009). The purpose of this thesis is to constrain this relationship between the loss of porosity and the effective viscosity of volcanic rocks undergoing viscous deformation. It is important to assess this because the effective viscosity will control the fragmentation of the material. The degree of fragmentation and porosity both contribute to the permeability which will determine the potential for effusive degassing and volcanic recharge. This study consists of high temperature compaction experiments on cores of Mount Meager pumice at constant loads and constant displacement rate using the Volcanic 2 Deformation Rig. The porosity of deformed and undeformed cores are determined by helium pycnometry.
The style of deformation (viscous or brittle) is determined by monitoring acoustic emissions. This produces results showing the relationship between stress, strain, and porosity. The acoustics show the viscosity by which brittle deformation begins at a particular temperature. These results show the relationship between effective viscosity, and porosity of pyroclastic material and the transition between viscous and brittle behavior with changes in porosity and viscosity.
3 Chapter 2: Background 2.1 Geological Background: Mount Meager Volcanic Complex The Mount Meager Volcanic Complex (MMVC) is located in Southwestern British Columbia, approximately 150 km north of Vancouver. This calc-alkaline stratovolcano complex is part of the Garibaldi Volcanic Belt, the northernmost end of the Cascade Volcanic Arc (Green et al., 1988; Read, 1990; Sherrod and Smith, 1990). The MMVC is made of a number of partially overlapping volcanoes and consists of overlapping deposits of andesite lava flows, dacite domes and lava flows, pyroclastic and rock avalanche deposits, and peripheral basaltic lava flows and volcaniclastic deposits (Read, 1977a, 1977b). Activity of MMVC extends from 2.2 Ma to its most recent explosive eruption in 2350 BP (Clague et al., 1995; Leonard, 1995; Read, 1977a).
This most recent eruption deposited the Pebble Creek Formation (PCF). The PCF is predominantly dacitic to trachydacitic in composition and its geology is described by various authors (Hickson et al., 1990; Read, 1977a, 1977b, 1990; Stasiuk et al., 1996; and Stewart et al., 2002, 2008). During the subplinian phase of the 2350 BP eruption, a plume 15-17 km in height produced pumicious pyroclastic fallout deposits totaling 4.2.108 km3 (Andrews et al, 2012; Hickson et al., 1999). These fallout deposits cover slopes of the northeast end of the MMVC. Proximal deposits of this tephra reach a thickness of 80 m while thin (approximately 5 cm thick) distal layers have been identified in Alberta, approximately 500 km to the NE of the vent (Hickson et al., 1999; Nasmith et al., 1967; Westgate and Dreimanis, 1967). These fallout deposits are unconsolidated, well-sorted and clast-supported, and consist of approximately 90% juvenile, angular, white to cream to light gray pumice clasts (1?50 cm in diameter). Large clasts are commonly fractured, and bread crust textures on the surface are common.
Approximately 1?5% of the pumice clasts are banded (Hickson et al., 1999; Stasiuk et al.