In the last five years the JEOL-8600 electron microprobe hosted in the new labs at the Department of Earth Sciences of the University of Florence has been updated in both software and hardware components. The instruments is controlled by the XMAS, IDFix, HiMax, MaxView software packages (developed by SAMx) which allow to perform quantitative analyses utilizing the equipped four spectrometers, each constituted by two analyzing crystals. In addition to be involved in routine analysis, such as those performed to characterize the mineral chemistry of silicates, in the recent past the instrument has been used to "non-conventional" researches who have interested different fields of Earth Sciences sensu lato, such as Paleontology and Archeometry. In this context, the importance of analyses on materials such as bones, teeth, bryozoa, and phases such as apatites and oxides are invaluable in the interpretation of the processes responsible of their formation and evolution. The optimization of the analytical conditions was therefore properly approached adjusting several different instrumental parameters such as accelerating voltage, beam current and counting times. Besides adjusting these parameters, the calibration included the choice of the appropriate emission lines to be analyzed and the consequent selection of the analyzing crystal (and spectrometer) to be used in WDS analyses. For this purpose the calibration was mainly concerned in the minimization of the detection limits of the elements to be analyzed. The aim of this communication is to provide some examples of analytical set-up utilized during analyses of "non conventional" material. Thus, the acquired analyses of teeth (either enamel and dentin) and bones fossil remains of Ursus spelaeus from Grotta all'Onda cave (Camaiore, Italy) were invaluable to reconstruct the paleo-environment in which the animal lived. Similar information was obtained after analyzing Chiastosella bryozxoa from different depth in Southern Ocean (Antarctica). Appropriate analytical setting allowed to estimate MgCO3 mol% contents to be related to water temperature variations and climate changes. Further researches involved analyses on apatites from a pseudotachylite sample and its host rock collected south of Terranova Bay (Antarctica). These analyses have the aim to verify the depletion in minor and trace elements due to the pseudotachylite formation, as suggested by the variation of U contents in the pseudotachylite and its host rock, derived from apatite fission-track analysis. As a final example, an appropriate calibration procedure was necessary to measure out trace elements (e.g. W) in oxides and metallurgical slag, thought to be valid tracers in ancient metallurgical processes finalized to the production of Fe in Tuscany.
The utilization of the electron microprobe analyses to non-silicatic systems: examples of applications
Braschi E;Orlando A;Ruggieri G
2014
Abstract
In the last five years the JEOL-8600 electron microprobe hosted in the new labs at the Department of Earth Sciences of the University of Florence has been updated in both software and hardware components. The instruments is controlled by the XMAS, IDFix, HiMax, MaxView software packages (developed by SAMx) which allow to perform quantitative analyses utilizing the equipped four spectrometers, each constituted by two analyzing crystals. In addition to be involved in routine analysis, such as those performed to characterize the mineral chemistry of silicates, in the recent past the instrument has been used to "non-conventional" researches who have interested different fields of Earth Sciences sensu lato, such as Paleontology and Archeometry. In this context, the importance of analyses on materials such as bones, teeth, bryozoa, and phases such as apatites and oxides are invaluable in the interpretation of the processes responsible of their formation and evolution. The optimization of the analytical conditions was therefore properly approached adjusting several different instrumental parameters such as accelerating voltage, beam current and counting times. Besides adjusting these parameters, the calibration included the choice of the appropriate emission lines to be analyzed and the consequent selection of the analyzing crystal (and spectrometer) to be used in WDS analyses. For this purpose the calibration was mainly concerned in the minimization of the detection limits of the elements to be analyzed. The aim of this communication is to provide some examples of analytical set-up utilized during analyses of "non conventional" material. Thus, the acquired analyses of teeth (either enamel and dentin) and bones fossil remains of Ursus spelaeus from Grotta all'Onda cave (Camaiore, Italy) were invaluable to reconstruct the paleo-environment in which the animal lived. Similar information was obtained after analyzing Chiastosella bryozxoa from different depth in Southern Ocean (Antarctica). Appropriate analytical setting allowed to estimate MgCO3 mol% contents to be related to water temperature variations and climate changes. Further researches involved analyses on apatites from a pseudotachylite sample and its host rock collected south of Terranova Bay (Antarctica). These analyses have the aim to verify the depletion in minor and trace elements due to the pseudotachylite formation, as suggested by the variation of U contents in the pseudotachylite and its host rock, derived from apatite fission-track analysis. As a final example, an appropriate calibration procedure was necessary to measure out trace elements (e.g. W) in oxides and metallurgical slag, thought to be valid tracers in ancient metallurgical processes finalized to the production of Fe in Tuscany.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
