A friend says a person can never have enough Allende thin sections. It’s easy to see why. Here I offer thirteen photos without comment other than that all but the first are from a single slide and that all but the last have a field of view 3.1mm wide. That last has a FOV one half millimeter wide.
Ultra violet lamps for fluorescent mineral collectors are getting smaller and lighter. Batteries are better and, in the case of long wave UV (UVA) lamps, fluorescent tubes have given way to specialized light emitting diodes. LED light is focused with either a tiny integral lens or with a conventional flashlight reflector. Small, strong, narrow beam flashlights are available. Any light
Ahmed Pani was selling this brecciated L chondrite in Tucson in February 2017. The mineral dealer from Vienna had one slice with a distinct dark clast that I should have bought. Luckily he had a similar slice available when we saw him at the Munich show in October. It turned out to be beautiful in thin section. The dark clast
As might be expected, NWA 2798 L3.2 contains large, well defined chondrules and dark matrix. It also displays quite a variety of barred olivine features – coarse and fine, simple and otherwise. These thin section photos are from just two slides. The first six are from one and are all at the same scale with the fields of view 3.1
One of my first thin sections was Cole Creek H5. I’ve picked up a few more slides over time because it’s a fun meteorite to view in thin section. Barred olivine chondrules survived thermal metamorphism well. There is variety among the BO chondrules with a high proportion being compound. These photos are from four thin sections and are at different
CM2 meteorites are regolith breccias. They’ve been through cycles of crushing and lithification at an asteroid surface. They are dark with opaque matrix and varying amounts of chondrules, olivine aggregates, CAI and mineral grains. This is a sample of a CM2 fall that is reported to have distinct lithologies. Our samples, whose early field name was Jaipur, are dark and
I was given thirteen NWA 5000 Lunar (feldspathic breccia) thin sections to photograph. Each section has melt rock that merits attention. In some it appears as small puddles but in most it appears as veins, some traversing the full width of the sample. Of course thin sections are just that – thin (virtually two dimensional) sections taken from a three
In conjunction with the Meteoritical Society’s annual meeting which, this year, will be held in Santa Fe New Mexico, Dr. Tony Irving of the University of Washington will lead a post-meeting workshop {http://metsoc2017-santafe.com/workshops} Saturday, July 29, 2017. The topic is Martian Meteorites Under the Microscope. Here are shots of some of the thin sections he will have for viewing and
Ted Bunch and other researchers have described many shock induced features in this odd diogenite. We found some to photograph in a few thin sections, all viewed in cross-polarized light. Brecciation is a common result of shock. The clasts in this polymict breccia have a variety of textures. Mechanical twinning, also called shock twinning, is apparent in numerous mineral grains.
The assembly of polymict eucrites is neither gentle nor precise. It involves magma, impact excavation and cycles of rock crushing, mixing, lithification and more crushing. Drs. Wittke and Bunch tell us that NWA 2724 contains both subophitic and cumulate textured rock and is therefore polymict. Here is a thin section that shows this nicely.
Five years ago we took a general look at DaG 1040 and last March the subject was its metal content. Recently I got to look at two new thin sections of this meteorite and I am intrigued again by its variety of features and textures. The first five photos below survey the striking difference between two neighboring barred chondrules. Their
NWA 1685 LL4 is a handsome, interesting meteorite. Numerous stones were introduced in two releases by Dean Bessey and called BL. Individuals are glossy black on the outside and clearly brecciated on the inside. The brecciation is distinct because chondritic clasts differ in shock darkening, impact melt rock is featureless grey and many clasts are bounded by thin dark impact
Tieschitz is interesting in thin section. In our sample, large and small chondrules are set apart by opaque matrix. Radial pyroxene and cryptocrystalline chondrules display aqueous alteration. One large chondrule contains several relict grains. We see chondrules that appear to be radial olivine darkened with fine included particles, probably amphiboles or other alteration products, and by rust stains. There is
Sayh al Uhaymir 008 is one of the several pairings with SaU 005. These pairings have a total weigh of about 25 pounds. It is a Martian basaltic shergottite of a type sometimes called olivine-phyric. It is composed of olivine megacrysts in a finer grained groundmass of pigeonite and plagioclase. In these cross-polarized light (XPL) photos the large olivine crystals
We’ve seen curtains of microscopic bubbles before in meteorite thin sections. Readers might remember some in Greg Hupé’s NWA 6704 ungrouped achondrite, third photo. Here are others in another ungrouped achondrite that are intriguing for a couple of reasons. They often occur in multiple parallel sheets and they are sometimes quite wavy like heavy drapery. When viewing sections we should
