Hi Bea,
That's interesting, I haven't looked much into salt production.

Seaweed was used for multiple purposes in the past - food, fuel, manuring, fodder, and in some cases for industrial processes and I have seen salt production mentioned amongst these purposes in some sources.  Though some species were preferred for particular functions, it is usually difficult to distinguish the exact purpose, particularly if it is not very abundant in a particular deposit.

Rosie

Dr Rosie Bishop
Research Associate,
Dept of Archaeology,
Durham University,
South Road,
Durham,
DH1 3LE
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________________________________________
From: Beatrice Hopkinson [[log in to unmask]]
Sent: 22 November 2013 01:30
To: The archaeobotany mailing list; BISHOP R.R.
Subject: Re: Seaweed!

I was interested in your correspondence on the kelp (seaweed), as I am interested in prehistoric
salt production, and I've seen articles that presume that seeweed was used in salt (sodium chloride)
salt production, whereas to the best of my knowledge it was only used as potash to make soap and
such similar products that required a alkaline ash.

When sodium chloride ash was used it was generally as a filtrate to remove mineral impurities from
the common salt present.

You probably were already aware of all this though?

Bea

Beatrice Hopkinson
Hon. Secretary Oxford University Soc. LA Branch President, DBSAT (Droitwich
Brine Springs and ArchaeologicalTrust) Board AIA (Archaeological Institute
of America) Affiliate, Cotsen Institute of Archaeology, UCLA
818 766 7780


On Nov 21, 2013, at 9:06 AM, Rosie Bishop wrote:

Dear Rachel and Kath,

Thanks very much for the useful information!

Best Wishes

Rosie