chipdatajeffb
Allende quad animation
An animation of a couple dozen frames made using a DSLR and a petrographic microscope to provide cross-polarized light. This shows the birefringence colors obtained by turning one of the polarizers through about 90 degrees over the range of single frames that are animated here.
Click All Sizes to see the animation run.
The colorful rounded shapes are chondrules which have been shock-metamorphosed.
This is a first-rate thin section supplied by Jeff Rowell.
A thin section is a slice of a rock (in this case, a meteorite named Allende, for a pueblito in Mexico where these meteorites fell in 1969). The slice is cut from the rock with a diamond saw and then ground to a thickness of 30 microns. A rock sliced this thinly is largely transparent.
The Allende meteorites are of a type called carbonaceous chondrites and in addition to chondrules also contain interstellar dust particles as well as CAIs (Calcium-Aluminum Inclusions), which are thought to be the oldest unaltered particles in our Solar System.
The actual width of this field of view is a bit over ~1.6mm (was originally stated to be ~3mm). The string of conjoined chondrules stretching most of the way across the center of this image measures 1.4mm as near as I can manage to do it. Given the dimesions of this feature in pixels, the image scale is therefore ~ 352 pixels / mm.
The microscope setup used to make this image was a 6mpixel DSLR attached via an eyepiece projection adapter to a petrographic microscope using a 10X widefield eyepiece and an objective short-focus extension tube that does not allow me to calculate the magnification, sorry!.
Allende quad animation
An animation of a couple dozen frames made using a DSLR and a petrographic microscope to provide cross-polarized light. This shows the birefringence colors obtained by turning one of the polarizers through about 90 degrees over the range of single frames that are animated here.
Click All Sizes to see the animation run.
The colorful rounded shapes are chondrules which have been shock-metamorphosed.
This is a first-rate thin section supplied by Jeff Rowell.
A thin section is a slice of a rock (in this case, a meteorite named Allende, for a pueblito in Mexico where these meteorites fell in 1969). The slice is cut from the rock with a diamond saw and then ground to a thickness of 30 microns. A rock sliced this thinly is largely transparent.
The Allende meteorites are of a type called carbonaceous chondrites and in addition to chondrules also contain interstellar dust particles as well as CAIs (Calcium-Aluminum Inclusions), which are thought to be the oldest unaltered particles in our Solar System.
The actual width of this field of view is a bit over ~1.6mm (was originally stated to be ~3mm). The string of conjoined chondrules stretching most of the way across the center of this image measures 1.4mm as near as I can manage to do it. Given the dimesions of this feature in pixels, the image scale is therefore ~ 352 pixels / mm.
The microscope setup used to make this image was a 6mpixel DSLR attached via an eyepiece projection adapter to a petrographic microscope using a 10X widefield eyepiece and an objective short-focus extension tube that does not allow me to calculate the magnification, sorry!.