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 • Cam. 262 / le type Besançon

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Petrology
 • TF1 - Granite-tempered
 • [Sample thin section]
 • [Hi-res (DjVu) image]
 • TF2 - `Standard fabric`

Camulodunum type 262, le type Besançon and Central Gaulish granite-tempered ware

Petrological description of TF2

TF2 fabric is characterized in the hand specimen by sparse biotite visible on the sherd surfaces. It is a much finer fabric than TF1 but under the binocular microscope it can be seen to contain moderate grains of sand. This sand consists of well-sorted, subangular and rounded grains, on average c.0.5mm across. Larger reddish brown clay pellets are also present. A single thin-section, grouped with TF2, contains a much finer sand, with grains averaging c.0.2-0.3mm across, although sparse larger inclusions of the same types as those in the remaining sherds were present.

The inclusions consist, in roughly equal quantities, of felspars, altered felspars, quartz, and smaller quantities of lava fragments and biotite. Rare fragments of composite rock were also present and these tended to be larger, up to 2.0mm across.

The felspars were not normally identifiable, due to their alteration, but fragments of plagioclase and one fragment with graphic intergrowth were present. The rock fragments include a fragment of coarse-grained rock composed of quartz and muscovite, and a fine-grained rock composed of quartz, biotite and muscovite. The quartz was polycrytalline with a mosaic texture (crystal size c.0.2mm) and this suggests that the rock might be of high-grade metamorphic origin.

The clay pellets usually have a zoned structure, in which the zones vary in colour and texture. The outer zone is often darker and denser than the inner, like a crust.

The groundmass consists of anisotropic clay minerals and small fragments of muscovite up to 0.2mm long, quartz, biotite and clay pellets.

TF2 is similar to TF1 in that it too contains moderate amounts of biotite, black mica, and has inclusions which originate in a granite. In constrast, however, the inclusions in TF2 are definitely a detrital sand which contains material from several sources: acid igneous, volcanic, and metamorphic rocks. Furthermore, the abundance of muscovite in the clay matrix, and the absence of larger laths amongst the inclusions, suggests that the parent clay of TF2 contained muscovite but that the sand used to temper it did not.

Similar suites of rock fragments and minerals were seen in sand samples from Sully-sur-Loire (45-Loiret) and La Charité-sur-Loire (58-Nièvre) and brick samples from Orlèans (45-Loiret).

  • Samples: B103, B134, B135, B137, B143, B211, B221.
  • Three of the samples (B134, B135, B211) were similar in petrology to Rigby and Freestone's `Standard fabric' (Rigby and Freestone 1986).
  • A second group (B103, B137, B143, B221) don't have the fine amphibole and pyroxene in the matrix and fall outside the scope the `Standard fabric' as defined in print, but are clearly related.

Alan Vince
11th February 1990

Summary of thin-sections

Show more details of these samples
TS ID Site name form
128 Amboise Cam 102
211 Chartres Cam 262
216 Chartres White-slipped red ware flagon
217 Chartres White-slipped red ware flagon
218 Chartres White-slipped red ware flagon
219 Chartres White-slipped red ware flagon
220 Chartres White-slipped red ware 2-handled flagon
221 Chartres Dolia
2 Colchester Cam 102
103 Dambron Cam 262
39 La Charite-sur-Loire Sand sample
36 Orleans Cam 262
134 Orleans Cam 262
135 Orleans Cam 262
136 Orleans Cam 102
137 Orleans Cam 262
141 Orleans White-slipped red ware sherd
143 Orleans Cam 262?
145 Orleans White-slipped red ware sherd
146 Orleans White-slipped red ware sherd
147 Orleans Cam 102
148 Orleans Red-slipped ware
151 Orleans Red-slipped ware
155 Orleans Cam 102
266 Orleans Cam 102
171 Saint-Marcel White-slipped red ware handle
6 Skeleton Green
7 Skeleton Green Cam 102
8 Skeleton Green Cam 102
9 Skeleton Green
10 Skeleton Green Plate
12 Skeleton Green
40 Sully-sur-Loire Sand sample
223 Tours White-slipped red ware sherd
225 Tours Cam 102
 • Url: http://www.potsherd.org.uk/papers/cgmw/db/petro/tf2 • Author: • Last updated: 29 July, 2004 •