California State University, Northridge Ceramic Firing
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CALIFORNIA STATE UNIVERSITY, NORTHRIDGE CERAMIC FIRING TECHNOLOGY " IN THE MOCHE VALLEY, PERU A thesis submitted in partial satisfaction of the requirements for the degree of Master of Arts in Anthropology by James Robert Szabo ~ January, 1977 1'"·--~-----.,-··--·---~----"'---· -· -----------..-~~--~---·--"----~----~- .. , l The Thesis of James Robert Szabo is approved, Antonio Gilman (Date) Paul L. K1.rk (Date)/ Carol .;r_.I Mackey Committee Chairperson California State University, Northridge ii ------~--------------,~---------------------~ Dedicated to Janine ACKNOWLEDGMENTS I wish to express sincere appreciation to :carol Mackey. Her contributions to this work have been extensive. To mention just a few: She provided me the opportunity to participate in the Chan Chan .Moche Valley Project; secondly, she shared with me all :or the currently emerging unpublished articles from other scholars working on aspects of the Project; thirdly, for her constructive criticism and desire for this to be a worthy thesis; and finally, for the encouragement she offered when it was needed. I would also like to extend a special thank you to Diana Kamilli_, for her willingness to provide Carol and I with the results of her Thermoluminescence and X-ray Diffraction tests. iii r--, --·~~1 I . They proved to be indispensable to the scope and quality of this study. To my wife Sherry, a deep appreciation for her typing and editing skills so freely offerred throughout the research, and for her patience and understanding. l ___ J iv TABLE OF CONTENTS Page ACKNOWLEDGMENTS iii LIST OF FIGURES vii ABSTRACT viii INTRODUCTION 1 THE SAMPLE 4 DESCRIPTION OF THE CULTURE HISTORY IN THE MOCHE VALLEY 7 HYPOTHESES FOR ANALYSIS 13 Part I THE SIGNIFICANCE OF COLOR IN CERAMICS 16 COLOR AND TYPOLOGY 16 CAUSES OF COLOR IN POTTERY 19 CLAY FORMATION IN THE NORTH COAST VALLEYS OF PERU 24 BLACK CORES 28 COLOR VARIATION 31 COLOR ANALYSIS OF THE MOCHE VALLEY POTTERY 33 CONCLUSION 39 Part II APPARENT POROSITY 41 PHYSICAL PROPERTIES OF FIRED CLAY 43 POROSITY MEASUREMENTS 46 REFIRING TESTS AND POROSITY 48 CONCLUSIONS 52 v Page Part III PROBLEMS IN OPEN FIRING SITUATIONS · 56 FIRING ATMOSPHERES 59 FUELS 66 FUEL IN THE MOCHE VALLEY 71 PROCEDURES FOR OPEN FIRINGS 73 VARIATIONS IN FIRING PROCEDURES 77 NOTES ON.EXPERIMENTAL FIRING 81 CONCLUSION 94 Part IV SUMMARY OF CONCLUSIONS OF THE PROJECT 99 BIBLIOGRAPHY 106 APPENDIX 114 CHART 1 COLOR FIRING TEST 114 CHART 2 POROSITY MEASUREMENTS FOR THE MOCHE VALLEY SITE COLLECTIONS 118 CHART 3 FIRING TRENDS BY SITE COLLECTIONS FINEWARE 122 CHART 4 POROSITY AT 900°C 123 CHART 5 POROSITY AT 1150°C 124 l i l I I J vi LIST OF FIGURES Figure Page 1 The Moche Valley sherd sample. 6 2 Moche Valley relative chronology. 8 3 Ceramic ~iring phases in the Viru and Moche Valleys. 12 4 Color e~~ects of iron oxides. 23 5 Varieties with black cores in the Moche Valley sample. 30 6 Predictable color objectives ~or the Moche Valley potters. 38 7 Properties o~ fired ceramics. 43 8 Apparent porosity formula. 46 9 Branch fuel ~iring. 85 10 Cow dung fuel firing. 86 11 Comparative experimental ~irings. 93 12a. Pottery of Firing #1. 95 12b. Firing #1 with. layer o~ branch ~uel in place. 95 13a. Firing #1 at completion. 96 13b. Oxidized vessel ~rom Firing #1. 96 14a. Firing #3. 97 14b. Firing #3. 97 15 Dark spout is evidence o~ incomplete oxidation. 98 I ---·~---,..1 vii ABSTRACT CERAMIC FIRING TECHNOLOGY IN THE MOCHE VALLEY, PERU by JAMES ROBERT SZABO Master of Arts in Anthropology In this work, the ceramic site collections of the Chan Chan - Moche Valley Project (excavation period, 1969 - 1975) are analyzed from the perspective of firing technology. Assuming that changes in the firing techniques reflect significant cultural changes, the emphasis has been placed upon the technological behavior of the Moche Valley potters. The firing of ceramics is performed within the cultural system and is an expression of traditional movements made by the potters that are as culturally significant as kinship groups or architectural styles. From this posture, physical attributes of the varieties relating to firing were examined. viii The causes of color in earthenware clay are discussed in Part I. Color was found to be dependent upon iron oxides and carbonaceous impurities in the clay, Refiring tests conducted upon a representive sample from the total site collections indicate that the clay used is uniform throughout the various cultural periods. Variations in the color of pastes were found to be the result of the ability of potters of the various cultural periods to control the firing atmosphere. From this conclusion, typological catagories for color were developed, Porosity measurements were conducted in Part II of this study to provide comparative data on the ultimate firing ranges of the ceramics of individual cultural units. A profile of the development of firing technology in the valley resulted from the analysis. The sequence of development is from 1) uncontrolled oxidation and reduction, to 2) controlled oxidation, and finally to 3) uncontrolled oxidation . , and controlled reduction. The peak of firing excellence was attained under controlled oxidation conditions. The later firing practices were examined to determine whether the uncontrolled firings indicate a decline in technology. The porosity comparisons ix show that the later firing practices were accomplished at higher firing temperatures than the earlier cultural units. Evidence is presented to demonstrate that the technology of the potters of later cultural units was fully developed. As a culmination of the study of firing practices in the Moche Valley, firing experiments were accomplished. In Part III of this study, the relative difficulty of firing ceramics in open firing situations is discussed, Ethnographic descriptions of modern Peruvian potters is included to present the sequence of events in open firing situations. In the experiments, reduction and uncontrolled oxidation firings were found to be easier to accomplish than controlled oxidation firings. From the data obtained from the firings, it is evident that the ceramic technology of the Moche Valley continued to develop throughout the sequence of cultural units. The decline in the firing practices in the later cultural units is not a decline in technology, but rather the result of changes in pottery style. The functional aspects of the ceramics are discussed as an indication of why the later changes in quality occurred. X CERAMIC FIRING TECHNOLOGY IN THE MOCHE VALLEY, PERU INTRODUCTION THE POTTERY FOUND IN MOST archaeological sites that were occupied by man after he began to farm and to settle on the land has changed very little in its appearance since it was fired and used. Although most exca vated vessels are broken or exist only as remnants in the form of one or more pot sherds, they serve as important evidences of the people who made and used them. Sherds are little affected by burial in the earth--they endure while metals corrode and disintegrate, and objects made of bark, wood or skin decay. Pottery preserves in its shape, decoration and physical properties a permanent though very fragmentary record of some of man's activities. Therefore, it must be studied intensively if the archaeolo gist is to reclaim from it all that is possible of the re6ord remaining in such objects, and of their associations with other materials, in his excavations of ancient villages and towns. If the mineralogical, physical and chemical properties of pottery are selectively determined in the light of the archaeolo gical problem being studied, information can be obtained about the raw materials selected and used by the potter, their treatment before being formed into pots, the manner of fashioning the vessels and of fir ing them, and perhaps the uses to which they were put. The role of the potter as the active and controlling agent in these procedures must be kept in mind, and _the function of his products in his community cannot be overlooked, We are concerned with the analytical data of products made by man, data which will help us better to 1 2 understand this man's culture. Each study increases our historical knowledge of technological developments in areas of the world where ceramic products have been manufactured through long periods of time (Matson 1963:592). The comments of Matson on the value of studies in ceramic technology are characteristic of the new direction in analysis that contemporary archaeologists have taken towards more complete explanations of the cultural process. Archaeologists now have begun to demand more of excavated artifacts than the identification of their placement in time and space. The work of Anna Shepard (1956) on the various techniques of pottery analysis is the most comprehensive text for archaeologists. Early to recognize that the fabric of pottery held promise for new approaches to gathering data concerning artifact collections, her work has not yet been surpassed in scope. As well as her text on the scientific analysis of pottery, Shepard has developed an impressive bibliography in which she has used a broad variety of tests to extract valuable data from artifact collections casting new light on problems encountered at particular sites. A concise review of both optical and nuclear analytical methods is found in the work of D.P.S. Peacock (1970). 3 Lewis Binford (1962:218) elaborating upon the ideas of Leslie White, and Julian Steward, views the cultural experience as the vehicle in which man achieves a degree of efficiency in adapting to the natural environment. The physical resources and the ultimate potential of the environment are closely related to the technology that will be present in the adaptation process. The efforts of man to utilize and survive within the physical environment is achieved by means of his tools and social relationships which Binford recognizes as technology.