Chapter 6: Chert Acquisition Networks | Download PDF
New Introductory Paragraph by Randall Law, 2024
Finished artifacts (mainly blades and other implements) and production debris composed of chert (an opaque microcrystalline silicate) make up over one-third of Harappa’s rock and mineral assemblage. Multiple varieties of chert were used at the site during its early phases whereas only one type seems to have been utilized during the urban phase. In this chapter, samples of chert from sources across the greater Indus region are compared to artifacts from Harappa using Instrumental Neutron Activation Analysis.
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CHERT ACQUISITION NETWORKS
Chapter introduction – The three main types of chert at Harappa
Indus Civilization peoples, although heavy consumers of copper and skilled producers of copper-alloy implements, still chose to utilize chert to manufacture many of the tools (blades, drills, scrapers, awls, etc.) that they used in their daily lives. At Harappa, tools composed of this opaque variety of microcrystalline silicate (or, more commonly, the debris from the manufacture of them) make up more than one-third (37.21%) of the over 56,000 artifacts in the site’s rock and mineral assemblage (recall Figure 4.2). Chert also seems to have been the preferred stone for making the distinctively Harappan style of cubical weights. Visual examinations of this material sub-assemblage at Harappa indicate that there are three main macroscopically distinct types of chert represented in it (to see a selection of these refer back to Figure 4.3 B). A purplish-hued chert/chalcedony and a black-brown-colored chert are the two most abundant types in levels dating to the site’s earliest two occupational phases (Ravi and Kot Diji phases). Black-brown cherts occur throughout Balochistan (Aubry et al. 1988) and, prior to this study, material of this type found at Harappa was believed to have originated from that region (Meadow and Kenoyer 2001: 24). Artifacts made of a tan to gray-colored (tan-gray) chert that often has a distinctive banded pattern have been recovered from strata representing all periods at Harappa. This type appears to have been the only one used during the site’s urban phase (Period 3). Tan-gray chert that is sometimes banded is also found at Indus Civilization settlements across the entire Greater Indus region (Ratnagar 2001b: 64) and is widely believed to have originated in the extensive Rohri Hills chert quarries of northern Sindh (Allchin and Allchin 1997: 172).
In this chapter, I present an account of my attempts to determine from which regional geologic sources each of the three main macroscopically distinct types of chert in Harappa’s rock and mineral assemblage were most likely derived. For the purplish hued chert/chalcedony, this entailed only the evaluation of that type in relation to chert artifacts in other contemporaneous archaeological assemblages, information in the geologic literature and observations in the field. For the black-brown and tan-gray cherts, however, I was able to directly compare a small set of artifacts (Figure 6.1) from Harappa and the Harappan Period site of Nagwada in Gujarat to samples from potential sources using instrumental neutron activation analysis (INAA). I have provisionally concluded that the purplish hued chert/chalcedony probably comes from volcanic trap rock formations in regions to the north of Harappa. Black-brown chert artifacts from Harappa were almost certainly derived from sources of the site in the Salt Range. Although most of the tan-gray chert artifacts from Harappa and other Harappan sites like Nagwada are probably indeed from the Rohri Hills of Sindh, there are indications that other sources also may have sometimes been used.
Figure 6.4 shows the locations of the four trenches at Harappa from which 24 of the 25 chert fragments analyzed for this study came from. INAAderived elemental data for these artifacts samples and the geologic to which they were compared are listed in appendices 6.1 through 6.6. Appendix 6.7 lists the standardized (canonical) discriminant function coefficients for each of the figures (6.18, 6.30 and 6.31) in this chapter that were generated using canonical discriminant analysis (CDA). All regions, sites and chert sources discussed below are noted on figures 6.2, 6.10 and 6.21. I begin with a few brief observations/ remarks on the ubiquity of chert in the Greater Indus region and at Harappa.
The rest of Chapter 6 is in the attached PDF below.
Images
Figure 6.1 Chert samples from Harappa (numbered) and Nagwada (NGW) analyzed for this study. Numbers = appendices 6.1 and 6.4 and below.
Figure 6.2 Regions, sites and chert sources discussed in this chapter.
Figure 6.3 [A & B] Bedded, multi-colored ophiolitic chert/jasper formation at Barzai, North Waziristan. [C] Men from the Sadgai area, North Waziristan sitting atop blocks of brecciated jasper-chalcedony. [D] Detail of Sadgai jasper-chalcedony. [E & F] Bedded, multi-colored ophiolitic chert/jasper formation at Ashgar Tangi, northern Zhob District, Balochistan.
Figure 6.4 Harappa chert sample locations and contexts.
Figure 6.5 Temporal distribution of the 9,325 chert artifacts at Harappa from secure contexts.
Figure 6.6 The highly varied Early Harappan Period cherts, chert/chalcedonies and other microcrystalline silicates.
Figure 6.7 Radiolarian chert-jasper blades and fragments from the sites of [A] Rehman Dheri and [B] Lewan. Collections of the Sir Sahibzada Abdul Qayyum Museum of Archaeology and Ethnology, University of Peshawar. [C] Radiolarian chert-jasper hammerstones and flakes on the surface of Periano Ghundai.
Figure 6.8 The colorful but the fractured and brittle chert of the Amb Formation, Nilawahan Gorge, central Salt Range.
Figure 6.9 Left: The microlith-covered dunes near Gidali, Sikar District, Rajasthan. Right: Examples of the chert and jasper artifacts found there.
Figure 6.10 Central Salt Range. [A] Chert sources and prehistoric sites. [B] Nammal Gorge area.
Figure 6.11 Nammal Gorge, central Salt Range.
Figure 6.12 Black-brown chert nodules within the Sakesar Limestone Formation, Nammal Gorge.
Figure 6.13 Black-brown Sakesar chert tool-preform found in Nammal Gorge.
Figure 6.14 Black-brown Sakesar chert cores and nodule fragments (red arrows) and a gray Sakesar chert blade (blue arrow) among the Kot Dijian and Harappan Period materials on the surface of Musa Khel.
Figure 6.15 Black-brown Sakesar chert cores and flakes from [A & B] Rehman Dehri, [C] Lewan, [D] Hathial and [E] Harappa.
Figure 6.16 [A] The Great Limestone Formation near Riasi, Jammu above the point where the Chenab River emerges onto the Punjab Plain. [B] Black Great Limestone chert at Mari nala. [C] Black Great Limestone chert at Jangleghari.
Figure 6.17 [A] The Bolan Pass at Dozan, Balochistan. [B] Large pod of black chert in Moro limestone.
Figure 6.18 Black-brown chert artifacts from Harappa compared to black chert samples from three geologic sources.
Figure 6.19 Various tan-gray type chert artifacts from Harappa. [left-to-right] blade tools, blade core, weight blank or celt roughout?, bead and cubical weight.
Figure 6.20 The Rohri Hills.
Figure 6.21 Map of the Rohri Hills showing the four locations sampled for this study.
Figure 6.22 Limestone mining at Rohri, on the northern tip of the Rohri Hills.
Figure 6.23 Banded tan-gray chert from Rohri.
Figure 6.24 Harappan Period quarries and workshops near Adam Sultan at Shadee Shaheed.
Figure 6.25 Chert debris covering the ground surface at Shadee Shaheed.
Figure 6.26 [A] The prehistoric site of Kot Diji adjacent to the fort of the same name. [B] A tan chert blade at Kot Diji. [C] Chert nodules eroding from the limestone bedrock below the Kot Diji fortifications.
Figure 6.27 The low-lying limestone mesas called the Kandarki Hills.
Figure 6.28 Chert blade production debris at Kandarki.
Figure 6.29 [A] Tan chert sample from the Mohmand Agency, NWFP. [B] Gray Chilton Limestone chert samples from the Kalat District, Balochistan. [C] Gray Sakesar chert samples from Buri Khel nala - Salt Range, Punjab.
Figure 6.30 INAA results: Tan-gray chert artifacts from Harappa and Nagwada compared to geologic samples from sources in four regions.
Figure 6.31 INAA results - Tan-gray chert artifacts from Harappa and Nagwada compared to geologic samples from sources in select regions.
Figure 6.32 Percentage of chert artifacts at Harappa sampled by context.
Figure 6.33 A large tan-gray chert nodule with its cortex removed. From the Harappa Museum Reserve Collection.
Figure 6.34 Chert artifacts with cortex and nodules fragments at Harappa.
The Chapter section titles are:
Chert in the Greater Indus region
Chert at Harappa
Purple chert/chalcedony and other minor Early Harappan material sub-varieties
Black-brown chert
Potential sources of black-brown chert
Sakesar Limestone, Salt Range, Punjab
Great Limestone, Jammu
Moro Formation, Bolan Pass, Balochistan
Potential black-brown chert sources not included in this study
INAA/CDA comparison of black chert artifacts to potential sources
Tan-Gray (Rohri?) chert
Rohri Hills, Sindh
Rohri
Adam Sultan
Kot Diji
Kandarki
Other potential sources of tan-gray chert
Mohmand Agency, NWFP
Kalat, Balochistan
Buri Khel, Salt Range, Punjab
Tan-gray chert sources not included in this study
INAA/CDA comparison of tan-gray chert artifacts to potential sources
Chapter conclusion
