Desperately Seeking Suzanne: Photographs in Suzanne Chick's Adoptee-narrative Searching for Charmian

In 1994, Suzanne Chick published Searching for Charmian, an adoptee autobiography that relates Chick's discovery of her birth-mother's identity. Chick had been aware from a young age that she was adopted, but only discovered in middle age that her birth-mother was well-known Australian author and journalist, Charmian Clift.Unlike the reconciliation trajectory that many adoption autobiographies take, a physical reunion between Clift and Chick was impossible as Clift committed suicide in 1969. In the absence of any prospect of physical reunion, Searching for Charmian relies upon other narrative structures. Resemblance as a marker of familial relationship becomes the text's organising principle, one that is thrown into relief with the numerous photographs Chick encounters in the course of her search, and a number of which are reproduced in the text. Significantly, the photographs of Clift are not only, or merely, the person they represent; Chick's narrative insists on the specific context of her adoption in order to create and read these photographs anew. The photographs are integral components of the life-narrative that turns around the importance of resemblance and difference in establishing this adoptee's identity. They are also potent markers of the ways in which visual media can transform ideas of family, of social relations and of the self

Why aqueous alteration in asteroids was isochemical: high porosity≠high permeability

Carbonaceous chondrite meteorites are the most compositionally primitive rocks in the solar system, but the most chemically pristine (CI1 and CM2 chondrites) have experienced pervasive aqueous alteration, apparently within asteroid parent bodies. Unfractionated soluble elements suggest very limited flow of liquid water, indicting a closed-system at scales large than 100's μm, consistent with data from oxygen isotopes, and meteorite petrography. However, numerical studies persistently predict large-scale (10's km) water transport in model asteroids, either in convecting cells, or via ‘exhalation’ flow — an open-system at scales up to 10's km. These models have tended to use permeabilites in the range 10− 13 to 10− 11 m2. We show that the permeability of plausible chondritic starting materials lies in the range 10− 19 to 10− 17 m2 (0.1–10 μD): around six orders-of-magnitude lower than previously assumed. This low permeability is largely a result of the extreme fine grain-size of primitive chondritic materials. Applying these permeability estimates in numerical models, we predict very limited liquid water flow (distances of 100's µm at most), even in a high porosity, water-saturated asteroid, with a high thermal gradient, over millions of years. Isochemical alteration, with flow over minimal lengthscales, is not a special circumstance. It is inevitable, once we consider the fundamental material properties of these rocks. To achieve large-scale flow it would require average matrix grain sizes in primitive materials of 10's–100's μm — orders of magnitude larger than observed. Finally, in addition to reconciling numerical modelling with meteorite data, our work explains several other features of these enigmatic rocks, most particularly, why the most chemically primitive meteorites are also the most altered