Thursday, 22 May 2014

Memento Mori

Been working on this for a while, inspired by the baby burial from the Neolithic settlement of Catalhoyuk last year. I've always felt neutral about working with human remains, and the picture of the tiny skeleton being uncovered by Barbara Betz in 2013 was the first time it's given me a lump in the back of my throat. The scientist in me is all for studying human remains, but I wonder what these people would have felt about their infant being excavated. We're talking here about a culture that was fascinated with skull removal so who knows! Perhaps these new feelings are a result of being a parent (I almost said recently but it's getting close to 1 year!) - a good example of how our own personal situation influences the way we perceive the past.

Beneath the floors are hidden treasures,
In secret kept, the bones are sealed
Of those now gone who’ll dream forever,
They wait their time to be revealed.
The days they pass without perception
The nights in silent shadow fly,
Lost to time’s endless reflection,
The memory of the past may die

Eternal endless ages musing,
Encased within the silent earth.
But whereupon the time is chosen,
To grant these souls a new rebirth.
With trowel aside the softest brush
Brings slowly forth the ashen limbs
The soil removed with gentlest touch
Reveals the bones with deftest skill

Feelings can be strong as passions,
What did these long gone children dream?
Who felt grief upon their passing?
We craft our tales ‘round death it seems
Do they want to tell their story?
Or rather would they ask us why?
Would they say, memento mori
Remember that you too will die.

Saturday, 3 May 2014

Micrograph of the Month: Dissolution of Spherulites

This post follows on from the Manganese Micrograph Mystery I posted a while ago. Blog followers will remember I posted some images of layered ruminant dung which had a distinctive black 'speckled' appearance, a bit similar but not quite the same as Mn staining.
Thanks to my readers the mystery was solved through the kind contributions of Hans Huisman. Huisman is a geoarchaeologist with expertise in degradation and preservation of archaeological materials. He suggests that manganese would produce more dendritic like patterns, and that instead this appears to be iron sulphide staining. Iron sulphides include minerals such as pyrite, which can oxidise to rust. This type of staining can be recognised in OIL as having a 'metallic' lustre, or smaller particles, such as we have here, can be examined using reflectance microscopy at a high magnification. So I'll be doing that asap. For now I wanted to share this image showing the possible impact this staining has had on the dung spherulites. In the top image (PPL) we can see the fragments of dung (1) and the speckled appearance of the metal salt staining (2). In the lower image (XPL) we can see the typical birefringance of the animal dung and the calcareous spherulite particles that are produced in the animal gut. However some of the spherulites (i.e. those that have the staining) have started to dissolve. The staining appears to 'infill' the spherulites, masking the distinctive cross pattern that is used to identify them in XPL. Interestingly similar features can be seen e.g. on diatoms in lake sediment.