This document summarizes research using amphibole thermometry to compare crystallization temperatures in plutonic and volcanic systems. Analysis of 106 amphibole grains found that 25 showed thermal zoning, with normal zoning (cooling from core to rim) most common. Grain sizes varied between systems, with the largest grains in granitoids. Results provide evidence that recharge of magma occurred in plutons, causing reheating of grains. Future work will further examine relationships between zoning and rock units to better understand magma mixing processes.
The document discusses estimating air and snow surface temperature evolution in East Antarctica using passive microwave remote sensing. Key points:
- Passive microwave sensors have been monitoring Antarctica since the 1980s, providing multiple images per day, but the continent remains undersampled.
- Correlation analysis between brightness temperature (Tb) measurements from sensors and in situ snow/air temperature data show Tb is closely related to snow temperature at different depths.
- Linear regressions were used to retrieve snow temperatures at depths from 0-10 meters using Tb, achieving good correlation (R2 > 0.9) and standard errors around 2°C.
- Air temperature was also retrieved but with lower accuracy (RMSE 4-
Steady-state thermal gradient induced by pulsed laser excitationSylvain Shihab
Â
This document presents a method to quantify the steady-state thermal gradient induced by pulsed laser excitation in a ferromagnetic layer. The method uses the coercive field of the ferromagnetic layer, which is temperature dependent, as a thermometer. By recording hysteresis cycles spatially across the laser heated spot using magneto-optical effects, the temperature profile is determined. Analysis of the results using the heat diffusion equation provides values for the thermal conductivity of the layer/substrate and the thermal resistance at the interface. This allows quantitative modeling of laser-triggered magnetization dynamics accounting for transient temperature effects.
The passage discusses the importance of summarization in an age of information overload. It notes that with the massive amount of online information available, being able to quickly understand the key points of documents is crucial. The ability to produce concise yet informative summaries can help people navigate large amounts of content and identify what is most relevant or important to their needs.
This document summarizes a study that measured physical properties of cores from a 15m borehole in Livingston Island, Antarctica. Thermal conductivity and diffusivity were measured on dry cores and varied between 3.02-3.32 W/mK and 1.42-1.64 x 10-6 m2/s respectively. Porosity was low at 1.1-1.8% and density ranged from 2640-2666 kg/m3. Heat production across the borehole was 1.698 μW/m3. Temperature measurements showed an average annual temperature of -1.76°C with a thermal amplitude of 7.71°C. The cores were composed of sandstone. Physical
Thermal Analysis of Passive Radiator for Inter Planetary Space ApplicationsShailesh Rajput
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The study aims to appraise the merits of using Passive Radiators for Interplanetary Space Applications as it draws no power from the satellite system, and measuring its Effectiveness in Dissipating the heat developed inside the payload to space against Environmental Backloads incident over its surface from the Celestial Surroundings.
It maintains the desired temperature range by Controlling Conductive and Radiative Heat Paths through the selection of Geometrical Configurations and Thermo-Optical Properties of the surface in addition to savings in Mass and Power respectively which has always been a crucial element in spacecraft design and configuration.
A Parametric study is conducted to explore the scopes of using Passive Radiators. The entire system is Modelled and Simulated in FEA software UG NX 7.5 with a Flat Plate Radiator used in the initial Space Thermal Analysis. Correlations between Heat Transfer Capacity, Thermal Backloads, Radiator Area and the Operating Temperature are investigated to provide Design Guidelines for Consistent and Predictable Performance with minimum Degradation in a thermally stable orbit.
The document defines temperature and absolute temperature in Celsius and Kelvin scales. It explains how to convert between Celsius, Fahrenheit, and Rankin scales, and lists the highest and lowest points on each scale. It derives the general gas equation and defines specific volume as the ratio of a substance's volume to its mass. Specific volume units and the formula are provided. Systems and surroundings are defined in thermodynamics.
The document describes several experiments analyzing heat transport through saturated sediments. A sandbox model was used to study heat flow, showing a cold front moving through the saturated zone over 3-5 hours. These results were modeled using TOUGH2 software. A flume experiment monitored temperature changes over 8 hours as the stream and groundwater reached equilibrium. Distributed temperature sensing (DTS) was then applied, measuring temperature variations in the flume induced by upstream heating. The high precision DTS data validated other measurements and provided spatial and temporal data on heat transport through the saturated sediments.
The document discusses estimating air and snow surface temperature evolution in East Antarctica using passive microwave remote sensing. Key points:
- Passive microwave sensors have been monitoring Antarctica since the 1980s, providing multiple images per day, but the continent remains undersampled.
- Correlation analysis between brightness temperature (Tb) measurements from sensors and in situ snow/air temperature data show Tb is closely related to snow temperature at different depths.
- Linear regressions were used to retrieve snow temperatures at depths from 0-10 meters using Tb, achieving good correlation (R2 > 0.9) and standard errors around 2°C.
- Air temperature was also retrieved but with lower accuracy (RMSE 4-
Steady-state thermal gradient induced by pulsed laser excitationSylvain Shihab
Â
This document presents a method to quantify the steady-state thermal gradient induced by pulsed laser excitation in a ferromagnetic layer. The method uses the coercive field of the ferromagnetic layer, which is temperature dependent, as a thermometer. By recording hysteresis cycles spatially across the laser heated spot using magneto-optical effects, the temperature profile is determined. Analysis of the results using the heat diffusion equation provides values for the thermal conductivity of the layer/substrate and the thermal resistance at the interface. This allows quantitative modeling of laser-triggered magnetization dynamics accounting for transient temperature effects.
The passage discusses the importance of summarization in an age of information overload. It notes that with the massive amount of online information available, being able to quickly understand the key points of documents is crucial. The ability to produce concise yet informative summaries can help people navigate large amounts of content and identify what is most relevant or important to their needs.
This document summarizes a study that measured physical properties of cores from a 15m borehole in Livingston Island, Antarctica. Thermal conductivity and diffusivity were measured on dry cores and varied between 3.02-3.32 W/mK and 1.42-1.64 x 10-6 m2/s respectively. Porosity was low at 1.1-1.8% and density ranged from 2640-2666 kg/m3. Heat production across the borehole was 1.698 μW/m3. Temperature measurements showed an average annual temperature of -1.76°C with a thermal amplitude of 7.71°C. The cores were composed of sandstone. Physical
Thermal Analysis of Passive Radiator for Inter Planetary Space ApplicationsShailesh Rajput
Â
The study aims to appraise the merits of using Passive Radiators for Interplanetary Space Applications as it draws no power from the satellite system, and measuring its Effectiveness in Dissipating the heat developed inside the payload to space against Environmental Backloads incident over its surface from the Celestial Surroundings.
It maintains the desired temperature range by Controlling Conductive and Radiative Heat Paths through the selection of Geometrical Configurations and Thermo-Optical Properties of the surface in addition to savings in Mass and Power respectively which has always been a crucial element in spacecraft design and configuration.
A Parametric study is conducted to explore the scopes of using Passive Radiators. The entire system is Modelled and Simulated in FEA software UG NX 7.5 with a Flat Plate Radiator used in the initial Space Thermal Analysis. Correlations between Heat Transfer Capacity, Thermal Backloads, Radiator Area and the Operating Temperature are investigated to provide Design Guidelines for Consistent and Predictable Performance with minimum Degradation in a thermally stable orbit.
The document defines temperature and absolute temperature in Celsius and Kelvin scales. It explains how to convert between Celsius, Fahrenheit, and Rankin scales, and lists the highest and lowest points on each scale. It derives the general gas equation and defines specific volume as the ratio of a substance's volume to its mass. Specific volume units and the formula are provided. Systems and surroundings are defined in thermodynamics.
The document describes several experiments analyzing heat transport through saturated sediments. A sandbox model was used to study heat flow, showing a cold front moving through the saturated zone over 3-5 hours. These results were modeled using TOUGH2 software. A flume experiment monitored temperature changes over 8 hours as the stream and groundwater reached equilibrium. Distributed temperature sensing (DTS) was then applied, measuring temperature variations in the flume induced by upstream heating. The high precision DTS data validated other measurements and provided spatial and temporal data on heat transport through the saturated sediments.
Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) are thermal analytical techniques that measure changes in the mass and temperature of a sample as it is heated. TGA measures weight changes that occur as a sample is heated, providing information on physical and chemical phenomena like phase transitions and decomposition. DTA measures the difference in temperature between a sample and an inert reference as both are heated, revealing endothermic and exothermic reactions in the sample. Together, TGA and DTA can be used to characterize materials and determine their composition, purity, and thermal stability.
This document discusses Thermo gravimetric analysis (TGA), a technique where the weight of a substance is recorded as it is heated or cooled at a controlled rate. TGA is used to detect changes in mass that occur due to thermal events like desorption, absorption, and chemical reactions. Results are displayed as Thermo gravimetric (TG) curves that plot mass change versus temperature or time. The curves reveal temperatures where mass loss occurs due to decomposition or evaporation, as well as temperatures where the material is stable. TGA can be used to identify materials based on their characteristic temperature ranges of decomposition. Modern TGA instruments precisely measure weight changes, can rapidly heat and cool samples, and are often coupled to additional analytical techniques.
Thermogravimetric analysis (TGA) measures the change in weight of a sample as it is heated or cooled. It involves heating a sample in a controlled atmosphere and measuring its mass change over time or temperature. TGA provides information about physical and chemical changes that occur as the sample is heated, such as decomposition, oxidation, and vaporization. The results are displayed as a TGA curve, which plots mass or percentage mass change against temperature or time. TGA is useful for determining various characteristics of materials such as polymers, foods, and pharmaceuticals.
This document discusses thermal analytical techniques, specifically thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It provides details on the principles, instrumentation, factors affecting results, and applications of TGA and DSC. TGA measures the mass of a sample as the temperature changes and is used to determine decomposition temperatures. DSC measures the heat flow into a sample relative to a reference as temperature changes and can detect phase transitions like melting. Both techniques provide thermal data through continuously recorded curves.
Differential scanning calorimetry (DSC) is a thermoanalytical technique used to analyze characteristics of polymers and other materials. DSC measures heat flow into and out of a sample as it is heated, cooled, or held isothermally. By monitoring the heat difference between a sample and an inert reference, DSC can detect physical and chemical changes associated with phase transitions, such as glass transitions, melting points, and crystallization events. The document discusses the principles, instrumentation, applications, and interpretation of DSC analysis for studying various material properties and transitions.
One-dimensional thermal modelling of Acadian metamorphism in southern Vermont...Moinak Ghosh
Â
A brief presentation on the summary of Armstrong and Tracy's paper published in 2000 on the one-dimensional thermal modeling of Vermont, U.S.A. This was presented by me as a part of an internal assessment in the penultimate semester of my postgraduate course in Geology, Presidency University, Kolkata.
1) The document describes an experiment on radial heat conduction. Thermocouples were used to measure the temperature at different points in a brass cylinder as heat was applied to determine the thermal conductivity.
2) Thermal conductivity values were calculated at different measurement points using Fourier's law. The values ranged from 0 to 187.948 W/m°C.
3) Radial heat conduction is important in applications like heat exchangers and engines. It allows understanding how temperature varies from the center to outer surfaces of materials.
This document provides an overview of differential scanning calorimetry (DSC). DSC is a thermal analysis technique that measures the heat absorbed or released by a sample as it is heated, cooled, or held at constant temperature. It can be used to analyze properties such as glass transition temperatures, melting points, heat capacity, and more. The summary discusses:
1) DSC works by heating a sample and reference simultaneously while measuring the heat differential between the two. This allows it to detect endothermic and exothermic reactions in the sample.
2) Key measurements include glass transition temperatures, crystallization/melting points, and heats of reaction.
3) A typical DSC curve will
This lab manual document provides instructions for experiments on heat transfer in a Mechanical Engineering department. The first experiment listed is on heat transfer from a pin-fin apparatus. The objective is to calculate the heat transfer coefficient for natural and forced convection from a fin. The experiment involves measuring temperatures along a brass fin heated at one end while air passes over it naturally or in a duct. The second experiment listed is on heat transfer through a composite wall, and involves determining the total thermal resistance and conductivity of a wall made of different slab materials sandwiching a heater.
it is a method of miscellaneous instrumental analytical technique. it is one of the thermal analytical techniques used. it also has wide applications in the field of pharmacy.
Thermal analysis techniques measure how physical properties of materials change with temperature. Thermogravimetric analysis (TGA) specifically measures changes in mass with temperature or time in a controlled atmosphere. TGA works by heating a sample and measuring its weight loss, which provides information about decomposition reactions and thermal stability. It works by slowly heating a sample in a controlled furnace under an inert gas and precisely measuring weight changes with a high-precision balance. Factors like heating rate, sample amount and particle size can affect TGA results. TGA has applications in fields like polymers, ceramics, medicines and foods for properties analysis, reaction kinetics studies and quality control.
The document discusses heat transfer through conduction, describing how temperature distribution is governed by conservation of energy and Fourier's law. It covers steady vs transient heat transfer, classification of conduction problems, and the thermal resistance concept for analyzing systems with multiple materials. Examples are provided to illustrate how to set up and solve one-dimensional conduction problems using the appropriate heat equation and boundary conditions.
Thermal diffusivity is a physical property that measures how quickly a material responds to changes in thermal energy. It is the ratio of a material's ability to conduct heat to its ability to store heat. Materials with higher thermal diffusivity respond faster to temperature changes. Thermal diffusivity can be measured directly using methods like the flash method or indirectly using temperature history charts. Newton's Law of Cooling states that the rate of heat loss from a body is proportional to the difference between the body's temperature and the temperature of its surroundings. This law can be used to model and predict how quickly hot water in pipes will cool over time.
Thermal analysis techniques like differential scanning calorimetry (DSC) measure properties of materials as they change with temperature. DSC works by comparing the heat flow into a sample and reference as both are heated. If the sample absorbs or releases more heat than the reference during physical transformations like melting, it can determine purity and reaction details. DSC provides information on phase changes through endothermic or exothermic peaks in its output graph. Instrument factors and sample amount/shape can impact DSC curves and their interpretation.
Thermogravimetric analysis (TGA) measures the change in weight of a substance as it is heated. It works by heating a sample at a controlled rate and measuring its weight loss over time or temperature. Changes in weight are caused by physical or chemical processes like decomposition or evaporation. A TGA curve shows the weight change of a sample as it is heated. It can identify decomposition temperatures and determine purity and composition. Differential thermal analysis (DTA) measures the temperature difference between a sample and an inert reference as both are heated. It identifies exothermic and endothermic transitions in a sample through temperature differences between the sample and reference.
Thermogravimetric analysis involves measuring the weight changes of a sample as it is heated. The instrumentation includes a balance, heating device, temperature control unit, and mass and temperature recorder. Samples are typically solids that undergo reactions involving gas absorption or evolution. The furnace heats the sample while a thermocouple measures its temperature. The balance and recorder track the sample's mass changes as a function of rising temperature. Thermogravimetry provides information about thermal stability, reaction rates, and composition changes.
Thermogravimetric analysis (TGA) measures the mass of a sample as the temperature changes. There are three main types: isothermal, quasistatic, and dynamic. TGA provides information about physical and chemical phenomena like phase transitions and decomposition reactions. The sample is heated and weight changes are measured and plotted in a thermogravimetric curve. TGA is used to study material properties, composition, and stability in applications like pharmaceutical analysis and catalyst studies.
This document provides an overview of thermogravimetric analysis (TGA). TGA involves measuring the mass of a substance as it is heated or cooled over time in a controlled temperature program. It summarizes the principle, instrumentation, example curve, applications, limitations, and factors affecting results of TGA. The instrumentation section describes the sample holder, microbalance, programmable furnace, temperature control/sensor, and data readout components of a TGA instrument. Common applications include determining thermal stability, material characterization, and compositional analysis.
Differential scanning calorimetry (DSC) is a thermoanalytical technique that measures the heat flow into a sample as it is heated, cooled, or held at constant temperature. DSC curves show endothermic or exothermic reactions as peaks or dips. DSC is used to determine glass transition temperatures, crystallization and melting points, purity, and heat capacity. It has applications in pharmaceutical analysis, polymer curing processes, and general chemical analysis. DSC provides information about physical and chemical changes by measuring the difference in heat flow between the sample and reference.
Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) are thermal analytical techniques that measure changes in the mass and temperature of a sample as it is heated. TGA measures weight changes that occur as a sample is heated, providing information on physical and chemical phenomena like phase transitions and decomposition. DTA measures the difference in temperature between a sample and an inert reference as both are heated, revealing endothermic and exothermic reactions in the sample. Together, TGA and DTA can be used to characterize materials and determine their composition, purity, and thermal stability.
This document discusses Thermo gravimetric analysis (TGA), a technique where the weight of a substance is recorded as it is heated or cooled at a controlled rate. TGA is used to detect changes in mass that occur due to thermal events like desorption, absorption, and chemical reactions. Results are displayed as Thermo gravimetric (TG) curves that plot mass change versus temperature or time. The curves reveal temperatures where mass loss occurs due to decomposition or evaporation, as well as temperatures where the material is stable. TGA can be used to identify materials based on their characteristic temperature ranges of decomposition. Modern TGA instruments precisely measure weight changes, can rapidly heat and cool samples, and are often coupled to additional analytical techniques.
Thermogravimetric analysis (TGA) measures the change in weight of a sample as it is heated or cooled. It involves heating a sample in a controlled atmosphere and measuring its mass change over time or temperature. TGA provides information about physical and chemical changes that occur as the sample is heated, such as decomposition, oxidation, and vaporization. The results are displayed as a TGA curve, which plots mass or percentage mass change against temperature or time. TGA is useful for determining various characteristics of materials such as polymers, foods, and pharmaceuticals.
This document discusses thermal analytical techniques, specifically thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). It provides details on the principles, instrumentation, factors affecting results, and applications of TGA and DSC. TGA measures the mass of a sample as the temperature changes and is used to determine decomposition temperatures. DSC measures the heat flow into a sample relative to a reference as temperature changes and can detect phase transitions like melting. Both techniques provide thermal data through continuously recorded curves.
Differential scanning calorimetry (DSC) is a thermoanalytical technique used to analyze characteristics of polymers and other materials. DSC measures heat flow into and out of a sample as it is heated, cooled, or held isothermally. By monitoring the heat difference between a sample and an inert reference, DSC can detect physical and chemical changes associated with phase transitions, such as glass transitions, melting points, and crystallization events. The document discusses the principles, instrumentation, applications, and interpretation of DSC analysis for studying various material properties and transitions.
One-dimensional thermal modelling of Acadian metamorphism in southern Vermont...Moinak Ghosh
Â
A brief presentation on the summary of Armstrong and Tracy's paper published in 2000 on the one-dimensional thermal modeling of Vermont, U.S.A. This was presented by me as a part of an internal assessment in the penultimate semester of my postgraduate course in Geology, Presidency University, Kolkata.
1) The document describes an experiment on radial heat conduction. Thermocouples were used to measure the temperature at different points in a brass cylinder as heat was applied to determine the thermal conductivity.
2) Thermal conductivity values were calculated at different measurement points using Fourier's law. The values ranged from 0 to 187.948 W/m°C.
3) Radial heat conduction is important in applications like heat exchangers and engines. It allows understanding how temperature varies from the center to outer surfaces of materials.
This document provides an overview of differential scanning calorimetry (DSC). DSC is a thermal analysis technique that measures the heat absorbed or released by a sample as it is heated, cooled, or held at constant temperature. It can be used to analyze properties such as glass transition temperatures, melting points, heat capacity, and more. The summary discusses:
1) DSC works by heating a sample and reference simultaneously while measuring the heat differential between the two. This allows it to detect endothermic and exothermic reactions in the sample.
2) Key measurements include glass transition temperatures, crystallization/melting points, and heats of reaction.
3) A typical DSC curve will
This lab manual document provides instructions for experiments on heat transfer in a Mechanical Engineering department. The first experiment listed is on heat transfer from a pin-fin apparatus. The objective is to calculate the heat transfer coefficient for natural and forced convection from a fin. The experiment involves measuring temperatures along a brass fin heated at one end while air passes over it naturally or in a duct. The second experiment listed is on heat transfer through a composite wall, and involves determining the total thermal resistance and conductivity of a wall made of different slab materials sandwiching a heater.
it is a method of miscellaneous instrumental analytical technique. it is one of the thermal analytical techniques used. it also has wide applications in the field of pharmacy.
Thermal analysis techniques measure how physical properties of materials change with temperature. Thermogravimetric analysis (TGA) specifically measures changes in mass with temperature or time in a controlled atmosphere. TGA works by heating a sample and measuring its weight loss, which provides information about decomposition reactions and thermal stability. It works by slowly heating a sample in a controlled furnace under an inert gas and precisely measuring weight changes with a high-precision balance. Factors like heating rate, sample amount and particle size can affect TGA results. TGA has applications in fields like polymers, ceramics, medicines and foods for properties analysis, reaction kinetics studies and quality control.
The document discusses heat transfer through conduction, describing how temperature distribution is governed by conservation of energy and Fourier's law. It covers steady vs transient heat transfer, classification of conduction problems, and the thermal resistance concept for analyzing systems with multiple materials. Examples are provided to illustrate how to set up and solve one-dimensional conduction problems using the appropriate heat equation and boundary conditions.
Thermal diffusivity is a physical property that measures how quickly a material responds to changes in thermal energy. It is the ratio of a material's ability to conduct heat to its ability to store heat. Materials with higher thermal diffusivity respond faster to temperature changes. Thermal diffusivity can be measured directly using methods like the flash method or indirectly using temperature history charts. Newton's Law of Cooling states that the rate of heat loss from a body is proportional to the difference between the body's temperature and the temperature of its surroundings. This law can be used to model and predict how quickly hot water in pipes will cool over time.
Thermal analysis techniques like differential scanning calorimetry (DSC) measure properties of materials as they change with temperature. DSC works by comparing the heat flow into a sample and reference as both are heated. If the sample absorbs or releases more heat than the reference during physical transformations like melting, it can determine purity and reaction details. DSC provides information on phase changes through endothermic or exothermic peaks in its output graph. Instrument factors and sample amount/shape can impact DSC curves and their interpretation.
Thermogravimetric analysis (TGA) measures the change in weight of a substance as it is heated. It works by heating a sample at a controlled rate and measuring its weight loss over time or temperature. Changes in weight are caused by physical or chemical processes like decomposition or evaporation. A TGA curve shows the weight change of a sample as it is heated. It can identify decomposition temperatures and determine purity and composition. Differential thermal analysis (DTA) measures the temperature difference between a sample and an inert reference as both are heated. It identifies exothermic and endothermic transitions in a sample through temperature differences between the sample and reference.
Thermogravimetric analysis involves measuring the weight changes of a sample as it is heated. The instrumentation includes a balance, heating device, temperature control unit, and mass and temperature recorder. Samples are typically solids that undergo reactions involving gas absorption or evolution. The furnace heats the sample while a thermocouple measures its temperature. The balance and recorder track the sample's mass changes as a function of rising temperature. Thermogravimetry provides information about thermal stability, reaction rates, and composition changes.
Thermogravimetric analysis (TGA) measures the mass of a sample as the temperature changes. There are three main types: isothermal, quasistatic, and dynamic. TGA provides information about physical and chemical phenomena like phase transitions and decomposition reactions. The sample is heated and weight changes are measured and plotted in a thermogravimetric curve. TGA is used to study material properties, composition, and stability in applications like pharmaceutical analysis and catalyst studies.
This document provides an overview of thermogravimetric analysis (TGA). TGA involves measuring the mass of a substance as it is heated or cooled over time in a controlled temperature program. It summarizes the principle, instrumentation, example curve, applications, limitations, and factors affecting results of TGA. The instrumentation section describes the sample holder, microbalance, programmable furnace, temperature control/sensor, and data readout components of a TGA instrument. Common applications include determining thermal stability, material characterization, and compositional analysis.
Differential scanning calorimetry (DSC) is a thermoanalytical technique that measures the heat flow into a sample as it is heated, cooled, or held at constant temperature. DSC curves show endothermic or exothermic reactions as peaks or dips. DSC is used to determine glass transition temperatures, crystallization and melting points, purity, and heat capacity. It has applications in pharmaceutical analysis, polymer curing processes, and general chemical analysis. DSC provides information about physical and chemical changes by measuring the difference in heat flow between the sample and reference.
1. Amphibole Thermometry and a Comparison of Results from Plutonic and Volcanic Systems
Introduction
New calibrations are used (Putirka 2016 (Am Min, in press)) to estimate amphibole
(hornblende) crystallization temperatures within plutonic and volcanic systems. Results of
these systems are compared so as to test ideas of recharge of magma within plutons, and the
extent of thermal re-equilibration after mixing.
Amphibole compositions are obtained from EMPA for 106 individual grains. Thermometers
are used to reconstruct temperatures at successive phases of growth within each grain and
represent thermal zoning. These T-transects show trends of either heating or cooling from
core to rim, stable thermal conditions (constant T) throughout a grain, or no T-distance
correlation, with much scatter; variation exists between volcanic and plutonic systems in
crystallization temperature and grain size.
The three systems are examined:
• Lassen Peak (Northern California)
• Guadalupe Igneous Complex (GIC; Central Sierra Nevada foothills)
• Pine Flat Intrusive Complex (PFIC; Southern Sierra Nevada).
Trent Sherman (1); Keith Putirka (1); Alyssa De Los Reyes (1) Alexandra Pytlak (1); Barbara Ratschbacher (2)
(1) California State University, Fresno Dept. Earth & Env. Sciences 2576 E. San Ramon Ave. M/S ST90 93740; tsherman91@mail.fresnostate.edu
(2) University of Southern California Department of Earth Sciences 3651 Trousdale Pkwy Los Angeles, CA, 90089
Figure 1: FS2B-A, Grouping 27; Data Points #116-125
800
820
840
860
880
900
920
940
960
980
1000
0 25 50 75 100 125 150 175 200 225 250 275 300 325 350 375 400 425 450
Temperature(C)
Rim-core-rim distance across grain (ÎĽm)
Cross-Sectional Temperature Gradient
Good Data Bad Data
Centerofgrain
Grainboundary
Grainboundary
Figure 2: PF-G-090; Grouping 63; Data Points #183-192
700
710
720
730
740
750
760
770
780
790
800
810
820
0 25 50 75 100 125 150 175 200 225 250 275
Temperature(C)
Rim-core-rim distance across grain (ÎĽm)
Cross-Sectional Temperature Gradient:
GIC gabbro amphibole
Figure 3: 843CPX; Grouping 4; Data Points #208-213
860
870
880
890
900
910
920
930
940
950
960
970
980
0 10 20 30 40 50 60 70 80 90 100
Temperature(C)
Rim-core-rim distance across grain (microns)
Grainboundary
Above: cross-sectional temperature gradient showing the points of a hornblende grain
measured by electron microprobe. The transect starts (at zero microns) at the rim of the
crystal, works progressively through the center (around 125 microns) and to the rim at the far
end (near 250 microns). The grain preserves a record of reverse zoning; initially (during
growth of core) the surrounding temperature was relatively low, then temperatures increased
at least until the grain stopped growing. Although it appears that temperature rose quickly
then plateaued, nothing can be said about relative rates of increased temperature because it
is just as plausible that the grain experienced different growth rates; however, no information
can be constrained about growth kinetics here.
Above: granitic amphibole core-to-rim cross-section. Blue points show data that was
trustworthy, while orange points were returned with low weight percent totals (<95%).
Orange points were included to illustrate the size of the grain being measured (grain ending at
430 microns. A cooling trend is observed at the rims (normal zoning). This amphibole came
from a granitic intrusion near Pine Flat Lake, Ca.
Above: Volcanic amphibole cross-sectional temperature gradient. Vertical dashed line at 92
microns marks the end of the grain, where a reliable temperature estimation could not be
constrained with EMPA due to low major oxide weight percent total.
Trend shows either: 1) an asymmetrical growth pattern of the grain 2) oblique viewing angle of
cross section 3) a system that is relatively temperature stable and only reflects “noise” in the
temperature calculation as judged by the error bars.
Conclusion
• This is a viable method to determine thermal zoning trends within amphibole crystals
• Plutonic and volcanic amphibole grains can reveal cross-sectional temperature trends that
reflect how temperature conditions changed throughout the growth of those minerals.
• T changes may reflect magmatic mixing processes, such that 1) immobile grains are heated
by pulses of recharge magma, or 2) grains are pushed (or fall?) into different magma types
• This method seems best suited in estimating intrusive systems
• volcanic trends mostly lie within the margin of error
• Many plutonic crystals show symmetric zoning
Methods
1) EMPA: field samples were made into thin sections and analyzed by electron microprobe.
Individual grains were analyzed for composition along core-rim transects.
2) Filtering: criteria were applied to filter unreliable data points collected by EMP. Data were
determined to be reliable if weight percent totals were ≥95% and had hornblende composition
39.0% ≤ SiO2 ≥ 50.0%
0.5% ≤ Al2O3 ≥ 18.0%
9.0% ≤ CaO ≥ 13.0%
3) Temperature Plots:
T(oC) = 1781 – 132.74[Siamph] + 116.6[Tiamph] – 69.41[Fet
amph] + 101.62[Naamph]
Temperatures were graphed according to their relative position in the grain as indicated by the
rim-core-rim transect. Successive distances along the transect were normalized to the first
point measured at a rim (using the Pythagorean Theorem).
4) Qualitative Assessment: Plots were assessed for 1) thermal zoning and 2) trends between
volcanic and plutonic systems
Results
• Of 106 grains analyzed, 25 show thermal zoning; all others show no correlation
• Normal zoning (core-rim T decrease) was the dominant trend observed in all samples
• The average size of grains depends on the system it came from:
• Lassen volcanics averaged 199.6 µm across the short axis (27 grains; stdev=277 µm)
• GIC gabbros 428.8 µm (68 grains; stdev= 465 µm)
• Pine Flat Reservoir granitoids 842.7 µm across short axis (11 grains; stdev=235 µm)
Next Steps
• Analyze thermal zoning in context of the rock unit they were found in
• Determine if zoning corresponds to grain mobility between cold felsic magmas and hot
mafic magmas.
• Find extent of thermal re-equilibration after magma mixing
Grainboundary
Graincenter
Grainboundary
Graincenter?
Right: amphibole crystallization
T distribution of the Pine Flat
Intrusive Complex.
• High T limb corresponds to
granitoid outcrop at 1200 ft
elevation
• Low T corresponds to a
mafic/felsic mingling zone at
outcrop elevation 3950 ft
• Temperature difference may
result from difference in
crystallization depth within
pluton
V23B-3112
Granitoid
Mafic
Cross-Sectional Temperature Gradient: Lassen Volcanics