Although I have not seen examples or read any pieces on the subject, I understand second hand that there were instances of aboriginal peoples burning surface bituminous coal which, if 'dirty' and burned under the right conditions should produce slag as well as ash. What might pass for an historic era feature might be an aboriginal feature predating the European presence.
 
 
 
James G. Gibb

Gibb Archaeological Consulting

2554 Carrollton Road

Annapolis, Maryland USA ?? 21403

443.482.9593 (Land) 410.693.3847 (Cell)

www.gibbarchaeology.net ? www.porttobacco.blogspot.com
 
On 12/23/13, Allen Dart<[log in to unmask]> wrote:
 
In some of the prehistoric Hohokam culture hornos (large roasting pits) of
southern Arizona it is not uncommon to see rocks and pit linings that became
vitrified from the extreme heat that built up in some of the pits. I'll try
to find some references on this.

 

 

al

 

Allen Dart, RPA, Executive Director (Volunteer)

Old Pueblo Archaeology Center

PO Box 40577

Tucson AZ 85717-0577 USA

 520-798-1201 office, 520-798-1966 fax

 Email: [log in to unmask]

 URL: www.oldpueblo.org

 

Disclosure: Old Pueblo Archaeology Center's Executive Director Allen Dart is
a USDA Natural Resources Conservation Service cultural resources specialist
who volunteers his time to Old Pueblo. Views expressed in Old Pueblo
Archaeology Center communications do not necessarily represent views of the
U.S. Department of Agriculture or of the United States.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~

 

 

 

 

 

-----Original Message-----
From: HISTORICAL ARCHAEOLOGY [mailto:[log in to unmask]] On Behalf Of
Williams, Scott
Sent: Monday, December 23, 2013 5:51 PM
To: [log in to unmask]
Subject: Slag question

 

A pit feature was recently found here in WA state that looks like a typical
earth oven of the area (i.e., big unlined pit with charcoal and oxidized
soil), but instead of fire-cracked rocks it has some kind of "frothy"
looking slag- the material is black, hard and looks silica-rich/glassy, but
soft enough to crumble or break with some pressure. It doesn't look like
slag from iron working to me, but my experience with iron slag is pretty
limited. I'm looking for suggestions of other processes that might have
created the material, or any thoughts on what could produce black,
finely-vesicular slag. There's no glass or other historic debris in the pit
feature, and it looks like whatever created the slag was done in the pit-in
other words, it doesn't appear to be a refuse pit filled with clean-out from
another source.

 

If this sounds like anything you've encountered before, I 'd love to hear
from you!

 

Scott S. Williams

Cultural Resources Program Manager, WSDOT

Environmental Services Office, Mottman

PO Box 47332, Olympia, WA 98504-7332

Ph: 360.570.6651

Mobile: 360.485.5350

Fax: 360.570.6633

[log in to unmask]<mailto:[log in to unmask]>

WSDOT Cultural Resources
Program<http://www.wsdot.wa.gov/Environment/CulRes/default.htm> on the Web

 

"Development is not stifled by history, but enriched by it."