Sea-Salt Production During the Shang and Zhou Periods in Northern Shandong

Sea-salt Production during the Shang and Zhou Periods in Northern Shandong

Wang Qing & Zhu Jiping

Key words: northern Shandong Shang Zhou sea-salt production

Sea-salt in China is primarily produced along the East repeated Holocene period sea transgressions in the area. Coast, and the northern coast of Shandong 山东 is one During excavations, large numbers of kuixingqi 盔 important production locale. In recent years, a group of 形器 (helmet shaped vessels) were discovered and they Western Zhou salt production sites on the northern coast comprised over 90% of the ceramic assemblage from of Shandong have been excavated by Shandong Uni- the site. In addition to a large number of vessel versity and collaborators. They have conducted a broad fragments, a total of 6 complete or reconstructable ves- survey of associated sites in the counties and munici- sels were recovered. Both the rim diameter and height palities of northern Shandong and thereby collected a of these vessels are around 20cm, and the vessel walls valuable set of artifactual analytical data. This article are about 2cm thick. They are relatively robust contain- uses these data to discuss the production and technical ers and their exterior surfaces are characterized by coarse development of sea-salt manufacture in northern cord-marking (Figures 1:1; 2). On many of the interior Shandong during the Shang and Zhou period as well as surfaces of these vessels there were hardened white or the distribution of production and related questions in a greenish-gray residues about 1–3mm in thickness (Figure preliminary fashion. 2). Associated features include pits, ditches, and lenses of hard residue. Five small pits (H1–H5) with diam- Excavations at the Dahuangbeiyang Site eters at the mouth of 50cm and depths of 30–40cm were The site of Dahuangbeiyang 大荒北央 was excavated distributed among ditches. Each of these pits had brown- in 2001. It is located 16km southwest from the shore of ish-red clay applied on the interior surface. Ditch 1 (G1) the Laizhou 莱州 Bay and was occupied during the was an irregular bar shape. Its interior wall slanted Western Zhou era (ca.1000–900 BC). The stratigraphy inward. The exposed portion of this ditch is 7m long, at the site is approximately 1m thick and includes three 1–1.6m wide and 0.8–1m deep (Figures 3; 4). The lenses levels. The top level (1) is the modern topsoil while of hard residue were found in level 2 and primarily were levels 2 and 3 are Western Zhou in date. Level 2 is 20– interspersed between the other thin lenses of the stra- 50cm thick and composed of interlaced layers of a mix tum and covered relatively large areas with a hard of blackish ashy soil and greenish-gray soil and black- surface. These surfaces are ubiquitous and continuous, ish ash with saffron colored soil. This complex inter- and have a definite slope. The lenses are less than 1cm digitation of soil layers is dense and uniformly distrib- thick and very smooth. They also have a slightly bitter uted with a certain gradient. In areas where the preser- flavor and the earth above and below is slightly brighter vation is better, 40–50 separate layers can be than the typical soil from the stratum (Figure 5). distinguished. Each layer is extremely thin, between 1– Elsewhere, on top of a thin layer plant impressions in 4cm in thickness. In surfaces associated with these lay- greenish-gray earth excavations also unearthed a hard, ers many lenses of hard white deposits were discovered. white surface distributed in small clumps and less than Level 3 is 0–40cm thick and composed of brownish- 0.5mm in thickness. yellow fine sandy soil. It is discontinuous across the site. Below level 3 lies brown sand that is a mixture of The development of salt production techniques coarse sand particles and shell fragments lain down by The kuixingqi vessels and the dense lenses of ash

Volume 7 119 H1 N layer 3 H3 layer 3

primary earth H2 primary earth G1 H4 T1 H5 T2 T3

02m D1

3 Figure 3. Plan view of trenches T1–T3 at the Dahuangbeiyang site

disturb pit

4 2

Figure 1. Artifacts and features unearthed at Dahuangbeiyang in Shouguang 1, 2. kuixingqi vessels 3, 4. circular ceramic shards reddish brown clay

disturb pit

030cm

Figure 4. Plan view of pit H2

Figure 2. Kuixingqi vessel base from Dahuangbeiyang T1 ②:1 and soil that characterize the Dahuangbeiyang site dif- fer considerably from the typical nature of Shang and Zhou period sites from inner Shandong. Quite possibly, Figure 5. Hardened white surface in Level T3② at Dahuangbeiyang these differences relate to the special function of this site. We collected a sample from the white hard resi- pal chemical component of edible salt is sodium chlo- due associated with T2 in level 2 at the site and sub- ride (NaCl), which is a particularly unstable substance. jected it to XRD analysis. The primary component of At high temperatures and in moist environments it dis- this surface was quartz with a peak diffraction at 0.334 solves and dissipates very easily. When it dissolves it nm, and another peak indicated feldspar. The princi- can often leave behind quartz and feldspar residues

120 Chinese Archaeology which are less soluable, so it is quite possible that these from the northern Shandong region during the Shang hard surfaces are the remnants left behind after the dis- and Zhou period concerning kuixingqi we can recon- solution and evaporation of salt from brine (Figure 6). structed the development of the technical processes by Furthermore, plant ash contains sodium carbonate which concentrated brine was boiled to make salt as

(Na2CO3) and potassium carbonate (K2CO3) which are follows: First build a salt furnace, then place brine into easily soluble and can combine with the calcium ions and magnesium ions in brine to isolate the sodium chlo- ride and increase the salinity of brine. The plant ash found throughout level 2 spread over large areas prob- ably were brought by humans as part of the process of attempting to make the brine more saline. If we take

cps into consideration the small pits and the ditches at the site, the processes used at the site to increase the salinity of brine can be reconstructed in the following fashion: First feed subterranean brine into the ditches, 10 20 30 40 50 60 70 second feed this brine into an area covered with plant 20 ash, then scrape up the salty earth and put it into pits to Figure 6. XRD results of the sample of a hard white surface in dissolve and precipitate. These along with the green- level T2 ② at Dahuangbeiyang ish-gray and saffron colored earth lenses that were covered by plant ash were plausibly made to prevent the 2500 percolating downward of the brine. Two circular ceramic shards were possibly the tools used to scrape up 2000 2.82 the salty earth in this process (Figures 1:3; 4). 1500 The interior surfaces of kuixingqi (particularly that at 1.99 the bottom of the vessels) often have white or greenish- 1000

1.63

gray residue. We subjected samples of this residue to Intensity (cps) 500

1.70 XRF and XRD analyses and discovered that the salinity 3.25

1.41 of this residue is around 10%, clearly higher than the 0 salinity of the soil within which these vessels were 10 20 30 40 50 60 70 discovered. The primary chemical component of the 20 degree hard residue was calcium carbonate because this sub- Figure 7. XRD results from the sample of white crystallized resi- stance is left behind during the dissolution of salt and due on the inner surface of a kuixingqi vessel from H20b itself difficult to dissolve. We have also collected at the Liwu site samples of similar pottery with residues on the interior surface from the site of Liwu 李屋 in Yangxin 阳信 County also in the same region of northern Shandong and subjected it to chemical analysis. In these samples salinity of the residue was also greater than 10% and in some cases was nearly 20%. In that case, not only was the salinity level higher than the surrounding natural soil and soil from cultural levels, it was also clearly higher than other pottery fragments from the same site, and it seems that in some cases remnant salt crystals were pre- served on some specimens (Figures 7; 8). At Dahuangbeiyang the excavation area was relatively re- stricted and brine boiling facilities like stoves were not found. However, in Zhanhua 沾化 County near Yangxin Figure 8. Microscope photograph of the white crystallized residue furnace features with kuixingqi inside have been from the inner surface of a kuixingqi vessel from H20b discovered. If we bring together all the various evidence at Liwu

Volume 7 121 the kuixingqi and feed the furnace, after the brine has Reference Works boiled down and the salt has solidified into cakes, break Shandong Daxue Dongfang Kaogu Yanjiu Zhongxin 山东大 open the kuixingqi and remove the salt cakes. 学东方考古研究中心 (Research Center of Oriental Archaeology, Shandong University) and Shouguang Shi Salt production areas Bowuguan 寿光市博物馆 (Shouguang Municipal Museum) The abundant sub-terranean brine of the southern (2005). “Shandong Shouguang Shi Dahuangbeiyang Xi coastal area of the Laizhou Bay is a recent phenomenon. Zhou Yizhi de Fajue 山东寿光市大荒北央西周遗址的发 The concentrated level of brine resulted from the pen- 掘 ” (Excavations of the Western Zhou Site at Dahuang- etration of seawater inland during the high-water trans- beiyang in Shouguang City, Shandong). Kaogu 考古 gression of the Holocene period and after rapid (Archaeology) 12: 41–47. concentration, this seawater became buried. Recently, Wang, Qing 王青 and Zhu, Jiping 朱继平 (2006). “Shandong through concerted archaeological and geological Beibu Shang Zhou Kuixingqi de Yongtu yu Chandi Zailun 山东北部商周盔形器的用途与产地再论” (More on the Func- research, the ancient Holocene coastline of the northern tion and Production Locales of [Helmet-shaped Vessels] from Shandong area has been reconstructed. From 6500–5000 the Shang and Zhou Periods of Northern Shandong). Kaogu BP, the coastline was 9–10m above the current coast- 4: 61–68. line and at its Holocene apogee. Thereafter it began to Wang, Qing (2006). “Lu Bei Diqu de Xian Qin Yizhi Fenbu recede. By the Shang and Zhou period it had already yu Zhong Quanxinshi Hai’an Bianqian 鲁北地区的先秦 receded 20–40km. Through this process, we can be cer- 遗址分布与中全新世海岸变迁” (Distribution of Pre-Qin tain that the coverage area of the brine stratum was Archaeological Sites in Northern Shandong and the Evolu- around the location of the coastline at about 6500–5000 tion of the Holocene Sea-coast). Huanjing Kaogu Yanjiu BP, or to the north of the line 9–10m above the present 环境考古研究 (Environmental Archaeology Research) Vol. coastline. The northern Shandong coastal areas includes 3. Beijing: Beijing Daxue Chubanshe 北京大学出版社 (Beijing University Press) pp. 64–72. more than one hundred localities where kuixingqi have been discovered recently and most of these are densely Wang, Zhenyan 王珍岩, Meng, Guanglan 孟广兰, and Wang, Shaoqing 王少青 (2003). “Bohai Laizhouwan Nan’an Disiji concentrated in a strip about 10m above the modern sea Dixia Lushui Yanhua de Diqiu Huaxue Moni 渤海莱州湾 level superimposed in the area where the Shang and Zhou 南岸第四纪地下卤水演化的地球化学模拟 ” period brine stratum would have been located. In this (Geochemical Simulation of the Development of Subterra- way we can know that the area of production of salt in nean Brine during the Quaternary along the Southern Coast northern Shandong during the Shang and Zhou period of the Laizhou Bay of the Bohai Sea). Haiyang Dizhi yu was primarily in a strip about 9–10m above current sea Disiji Dizhi 海洋地质与第四纪地质 (Oceanography and level. Quaternary Geology) 1: 49–53.

Note: The original paper, published in Wenwu 文物 (Cultural Relics) 2006.4: 84–90, with four figures, three photographic plates, is written by Wang Qing and Zhu Jiping. This summary is prepared by Wang Qing and English- translated by Rowan K. Flad 付罗文.

122 Chinese Archaeology