Week 6

Developments in 3D Presentation!

This week we experimented with making 3-D animations of our CT scans using VG Studio. It was a collaborative effort that resulted in several experimental videos and .gif animations, so we decided to dedicate a post to our discoveries.

Tour of the Week

We had a short tour of the Earth and Planetary Sciences (EPS) mineral collections and the electron microprobe lab. The EPS collections manager showed us some of their most interesting and attractive specimens. Many of their specimens are rare minerals or more common ones with unusual variations in composition. Some of us got to hold a huge "subway garnet" that was found under Manhattan during the construction of New York's sewer system.

The Subway Garnet. Photo credit: www.tmrives.com

Much like the invertebrate paleontology department, the collections staff in the EPS department are working on a large scale digitization project. We met their intern, who has been photographing minerals for an electronic database all summer. Because their collection is much smaller than the microfossil collection (in terms of total number of specimens), they have been able to photograph most of their specimens this summer.

The EPS department conducts a wide variety of research, from experimental petrology to meteoritics to mineralogy. While the work of EPS researchers and collections staff does not always overlap, they do work together to find specimens to use as standards for the electron microprobe. The microprobe needs to verify its element analyses with minerals with known compositions; minerals from the collection are perfect for this because they have already been characterized, and many contain rare elements.

Dr. Juliane Gross, a scientist in the EPS department, showed us the electron microprobe lab. Using this complex (and very expensive!) instrument, researchers obtain precise mineral composition data and create element maps of samples. The lab's most recent acquisition is a brand new carbon coater, which applies an extremely thin and even coat of nonconductive carbon to samples before analyzing them with the electron microprobe. This process ensures that the sample itself will not become negatively charged when exposed to the electron beam. As most of us interns have backgrounds in geology, we especially enjoyed this tour.

The Electron Microprobe Lab. Photo credit: www.amnh.org

State of the Project Address

So far, we have made approximately 2000 entries in the electronic database. Many slides have multiple fossils on them, so the total number of specimens is over 6000! This week, we also spent time standardizing our method for saving and backing up CT scan data on our computers, server, and external drives. This will ensure that the data is not lost, and that next year's interns can follow a specific protocol for organizing their CT scan files.

Foram of the Week

Shaun photographed a beautiful foram this week. The gold sheen is not natural; we dipped it in gold so that we could have an artsy photoshoot with it. Just kidding! Actually, this foram is coated in gold for a purpose: to make it suitable for scanning electron microscope (SEM) imaging. Because the minerals that make up the sample are not electrically conductive, a conductive coating must be applied before SEM analysis.

Another feature of this foram is that you can see the recrystallized interior where the last chamber is broken off at the top. This was helpful for us when choosing specimens for CT scanning. Although the exterior is very well preserved, the recrystallized interior means that we would be unable to see detailed internal structure in a 3D scan. 

It's been another productive week for the invertebrate paleontology interns, and we hope that the next week will be just as fruitful as we approach the end of the internship. 

Until next time,

The Microfossil Team