Ramat Bet Shemesh Regional Project 9789654062497, 9789654065856, 9654062496

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fAA Reports

RAMAT BET SHEMESH

LANDSCAPES OF SETTLEMENT: FROM THE ��

PALEOLITHIC TO THE OTTOMAN PERIODS

fAA Reports, No. 47

THE RAMAT BET SHEMESH REGIONAL PROJECT: LANDSCAPES OF SETTLEMENT FROM THE PALEOLITHIC TO THE OTTOM AN PERIODS

YEHUDA DAGAN

IN COLLABORATION WITH RUHAMA BONFIL AND ILAN SHARON

With contributions by Rina Y. Bankirer, Eldad Barzilay, Uri Baruch, Frida Ben-Ami, Arieh Bitan, David Bonfil, Noam Eitan, Shimon Feinstein, Amos Hadas, Liora Kolska Horwitz, Sonia Itkis, Hamoudi Khalaily, Boris Khesin, Hagit Levi Ben Ner, Ofer Marder, Oded Potchter, Uzi Salzman, Boaz Shacham, Ehud Shani, Ilan Sharon, Rina Zamir, Vladimir Zbenovich and Gila Zionit

ISRAEL ANTIQUITIES AUTHORITY JERUSALEM 2011

IAAReports Publications of the Israel Antiquities Authority

Editor-in-Chief Judith Ben-Michael Series and Production Editor: Ann Roshwalb Hurowitz Volume Editor: Shelley Sadeh Production Coordinator: Lori Lender Cover Drawing: Front Cover: Aerial photograph (1995), Kh. el- 'Alya [1] (Site 205), looking west (Y Dagan, photographer). Back Cover (top to bottom): Ottoman road (Site 327) from Beit Nattif (I:!. Bet Na(if) to Zanoal); Roman Milestone XXIV (Y Dagan, photographer). Cover Design, Typesetting and Production: Hagar Maimon Illustrations: Sonia Itkis, Ira Perova, Yaakov Shmidov and Natalya Zak Printing: Art Plus Ltd., Jerusalem Copyright © 2011, The Israel Antiquities Authority, Jerusalem POB 586, Jerusalem, 91004 ISBN 978-965-406-249-7 eISBN 9789654065856

www.antiquities.org.il

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--_ 'Uted cavewith extensions (1, 2); (j) calculated anomaly ofthe same cave with additional spaces (3, 4); (g) PAM ofthe excamred cave with exlensions (/, 2) and additional spacesfilled with magnetic soil, probably addinonal chambers (3, 4).

complex anomaly were added to the PAM (Fig. 6.3g:l, 2): Source J--all extension of the cave northward; Source 2---a further extension of the eastem ttulllel discovered n i the excavation. TIle calculated anomaly for this PAM reaches 20 nT amplitude, similar to that of the measw·ed anomaly, and shows the development of weak, tongue-shaped exten.sions. TIle branching of the magnetic anomaly due to the asswned tunnels

is still nconsistent i with the pattem of the magnetic anomaly. Better agreement of the calculated and measured magnetic anomalies was obtained by futher enlargement ofthe PAM adding additional spaces filled with magnetic soil (Fig. 6.3g:3, 4). hI smlllllluy, based on the magnetic survey results, an excavation in Sq A7 of c. 3S sq m revealed a cave with a large amomlt of well-preserved pottelY and finds typical

CHAPTER 6: THE MAGNETIC SURVEY

of the Early Bronze Age (Zbenovich, in prep. b). TIle results ofthe modeling infer that the IIOrthel.1l and eastem continuations discel.1led n i the excavation may lead to additional btulal chambers. Other magnetic ar1ltwblocks)

Fig. 7.1. Geologica/features (ret/fleet/from 1:2,500).

Landslide

FraclUlc/fault

CHAPTER 7: THE GEOLOGY

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Fig. 7.2. Bedrocksection:;, photographed dllring con:;tn/chon.

107

108

UZI SALZMAN

rock sequences and hiatuses in the sequences. Almost all the bore holes conducted within the Taqiya Fonnation in the Rarnat Bet Shernesh region revealed a certain hiatus in the continuity of the rock sequence, thus preventing simple correlations between two adjacent bore holes or two distant sequences of bore holes. Apparently, both the hiatuses and the complex, chaotic appearance of the rock are the result of either local or extensive landslides that took place during or immediately after the deposition of the Taqiya strata. The movements generated by the sliding and slumping of the marly constituents caused the irregular blend of the rock constituents, separated by the planes along which the actual movements occurred, as revealed in recent development works. As no single missing interval occurs in two adjacent bore holes, it would appear that erosion due to receding water and upheaval of the land can be excluded as causes for the formation of the hiatuses. It is evident that some landslides continued to occur during the time of the deposition of the Eocene Z:or'a Fonnation, or even later. This is confinned by relics of Eocene strata that are found within the limits of extensive landslides. The complex blend of the Taqiya rock later became consolidated under its own weight and the additional weight of the Eocene mass deposited above the marly rock, thus preserving its irregular, intricate appearance. No direct evidence was observed that could establish a relationship between new or recently developed landslides (see below) and sites of older Paleocene­ Eocene landslides. New landslides generally dissect older, blended masses, while 'older' cracks cause rock masses of varying volumes to crumble into the open spaces created by the newly developed landslides. However, it has been established that some of the ancient, local landslides were reactivated during younger periods. Due to the lack of exposure of a complete Taqiya section in the vicinity of Ramat Bet Shemesh, no accurate thickness of the fonnation could be established. However, it is assumed that the formation reaches a thickness of about 60 m.

appearances of flint nodules and beds of cherty chalk. In some instances, the chert appears crushed and fractured. Broken relicts of the z,or'a Fonnation appear within landslides, as observed near coordinatesNIG 1 998/6251 and along the banks of Na(lal Yannut, centered around NIG 1 9 83/6243 (see Fig. 7 . 1 ) . Boulders of nari rock originating above the Z:or'a chalk have also been recovered in bore holes within the streambed ofNa(lal Yannut. The thickness of the Z:or' a Formation along the western margins of Ram at Bet Shemesh increases from 1 2-20 m on its eastern edge, to 50-75 m near the Beit Jimal Monastery. Nari Rock Nan is a local term for a rock substance fonned close to the surface through the alteration of weak calcareous rocks, such as chalk and marl, creating a hard crust above the existing topography (see Chapter 8). The thickness of the nari crust in the region of Ramat Bet Shemesh ranges between 1 and 3 m (see Fig. 7.2). Two fonns of nan crust were identified: (1) continuous nan, located mostly on the hilltops; (2) disintegrated nari, composed of broken boulders separated by wide open fractures generally filled with clay, which is prominent along slopes or buried within landslides. Most of the disintegration originates in the mechanical process known as creep. A weak zone (or zones) fonns along the contact between the hard, strong nari crust and the weak calcareous rocks on which the crust develops. This zone includes caves that are often filled with clayey soil washed in by rainwater flowing on top of the nan surface. Also found are horizontal open fractures connected to the wide open fractures dividing the disintegrated nan. An additional phenomenon connected with this weak contact zone is the development of another zone of crumbled rock, immediately below the nari. The combination of the hard crust and the weak zone below it has been the main impetus for man to choose this horizon for the excavation of dwelling caves. STRUCTURE

The �or'a Formation, 'Adullam Member

The main constituents of this formation are chalk or limy chalk, somewhat bedded, with secondary

The Ramat Bet Shemesh region is included within the asymmetrical synclinal structure bordering the monoclinal Judean Hills structure that descends

CHAPTER 7: THE GEOLOGY

westward toward the hilly Shephelah region and ultimately toward the coastal plain ofIsrae!' In the eastern part of Ramat Bet Shemesh, the Z:or'a Formation is limited to the highest altitudes, generally 390+ m above sea level (asl), and forms about 10% of the surface. In the vicinity of the Bet Shemesh-Bet Guvrinroad, the lower boundary ofthe z:or'aFonnation could be located at about 290-300+ m as!. The general descent of the surface plane dividing the lower Taqiya Formation from the upper z,or'a Fonnation defines the structural dip ofthe Bet Shemesh syncline, a decline of 100 m over about 2500 m, or c. 2°. The general dip prevailing in the area under consideration allows the two existing rock fonnations to cover wide areas. The encountered rock is jointed. The joints are better preserved within the more brittle chalk and chalky limestone than in the more plastic layers of marl and marly chalk No systematic pattern could be ascribed to the existing joints. Joints play a major role in the configuration and development of landslides, and when exposed they fonn weak zones along which the rock collapses. No major geological fault has been observed in the vicinity of Ramat Bet Shemesh. All major movements observed in the survey are related to the displacements caused by massive landslides influencing the entire region (see below). However, signs of ancient straight lineaments are identified, postulating Eocene movements, the magnitude or direction of which are uncertain. These straight lines could be observed around coordinates NIG 19928/62637 and 1991 1162506 (see Fig. 7.1). MORPHOLOGY General Morphological Setting of the Ramat Bet Shemesh Region

The planned municipality of Ramat Bet Shemesh is situated in an area of moderate hills and spurs of soft rock dissected by ravines. The general topography slopes from east to west, with an average height of 400-420 m asl in the east, near Zanoal). and Beit Nattif, decreasing to an average height of350 to 370 m asl in the west, near the Beit Jimal monastery. The area of Tel Yannut, at 420 m asl, is an exception to the general rule. The slopes measured along the axes of the hilly crests and the ravines are moderate when compared to the perpendicular slopes: the slopes of the axes of the

109

crests range from 3 to 8° and those of the ravines reach only YZ-2YZ°, while the perpendicular slopes range from 1 3 to 26°. No fracture or fault line has been detected along which ravines have been cutting into the hills. Moreover, when lineaments were identified outside the ravines, no cutting process could be identified along them . Natural terraces, 1-5 m high, were observed along segments of the ravines, especially where secondary ravines merge into larger ones. These terraces, which separate the actual ravine from the descending slopes, were fonned by nari crusts or by accumulating nari boulders and blocks covered by alluvial soi!. In addition, steps of 1 to 3 m in height cross the ravines, some of which have been used in the past as foundations for masonry terraces. Development ofthe Morphology

Most of the morphological features in the Ramat Bet Shemesh region, i.e., scars and swells or steps, are surface manifestations of landslides and slumps that developed within the marly rock dominating the area under consideration. A landslide is defined as a downward sliding of a mass of rock or soil, and/or man­ made filL This movement takes place along defined concave, elliptical planes of weakness that developed within the rock as a result of infiltrating water. The traces of these planes can be identified at both the upper margins (as scars), and the lower margins (as swells or steps). A landslide can therefore be distinguished from a geological fault, as the latter is only traced along its upper margins, while the lower ones are obscured. The mechanical analysis of slope failures in soil and rock has been discussed in numerous publications (e.g., Hoeck and Bray 1981), and these conclusions form the basis for the morphological analysis presented here. Two types of landslides have been identified in the vicinity of Ram at Bet Shemesh: Massive Landslides These are identified by their extensive dimensions and the large volume of rock involved in the movement. In addition to the presence of marl, two further conditions are required for the development and progress of a massive landslide: 1 . An open space in proximity to the landslide, so that the moving mass can be contained.

110

UZI SALZMAN

2. A high water table within the marly rock, or altematively, the e.xistence of a sufficiently large body of waler to sanrrale the marl and weaken its mass, at least along potential or incipient weak planes. TIle Pleistocene era, several hlllldred thousand years ago, is the latesl lime for the development of appropriate geohydrological conditions. TIle margins of a Pleistocene sea, providing the requirements of an open space and a higher water table, have been identified n i close proxi.mity to Ramal Bet Shemesh. Sediments composed of limy sandstone, sand and gravel (conglomernte), i.e., "uTtar (also known as the Pleshet FomIalion), are located along NaJ:tal Soreq at a height of c. 200 m as!. Also identified are the rellmanls of Pleistocene river telTaces composed of conglomerate (knowu as the Nal lshon and Ai).uzam . Fonnations; see Gvirtzma.l.l and Buchbinder 1969), positioned at various elevations between 200 and 350 m asl, suggesting proximity to the seashore. TIle distance between the ancient Pleistocene seashore and the location of the major landslides ranges between 500 and 2500 m. TIle relatively steep gradient (I-5°) ofthe piezometric slllface of the water flow in the vicinity of Ralnat Bet Shemesh is a filllction of the hydraulic characteristics of the marl. In this region. the slope constinltes the n i temal surface of saturated rock. which fOlUled the weak surface upon which the landslide took place (see 'Hydrogeology', below). The massive landsides in the Ramat Bet Shemesh region are circmnscribed by an explicit line of faults, creating a rough geometry of 'uiangles', as can be observed in Fig. 7.1 (approximate coordinates): (a) western triangle-'intersection' NIG 19900/62500, 'westem end' NIG 19875/62525, 'eastem end' NIG 19920/62510: (b) eastem triangle-'intersection' NIG 19980/62500, 'westem end' NIG 19960/62510, 'eastem end' NIG 19970/62545: (c) one major weakness zone extending from NIG 19940/62450 to NIG 19800/62485. TIle position of massive landslides can be located by identifying the contact between two well-defined types of slopes: a. A steeper slope with a gradient of 15 to 25°, which is the eroded remnant ofthe upper pru1 ofthe plrule upon which the landslide took place, i.e .. the scar left by the siding l rock. b. A more moderate slope with a gradient of less than 10°, which develops on top of the subsiding mass of

rock. Upon this moderate slope we find accml1uiations of collapsed and eroded rock material (blocks of nari and cl1nl1bled fragments of chalk or lnarl), as well as layers of soil. TIle combined thickness of the collapsed and eroded rock material and soil that accllll1ulates on top of the subsiding mass may reach 1-5 Ill, fonning a suitable surface for ancient cultivation. Small Localized Landslides This type of landslide is probably the result of local instabilities that develop at the following locations: 1 . Rockfall, especially ofnari blocks: alongthe steeper slopes left by massive landslides (rare appearances n i the Ramat Bet Shemesh region: Fig. 7.3:a). 2. Rotational landslide: along ravines where the movement of a lower landslide causes instability to rock at higher elevations (Fig. 7.3:b). Tills process is enhanced by higher perched water tables (see below) and is pronllnent in the Rrunat Bet Shemesh region. 3. Rockslide: on the slopes of ravines perpendicular to their axes (rare appearances in the Ramat Bet Shemesh region; Fig. 7.3:c). All three types are observed as elliptical scars reaching a height of 1 to 5 m. Along the margins of some of these oval-shaped scars, small terraces were erected to facilitate the creation of patches of fertile soil for ancient cultivation.

b

Fig. 7.3. Example.l o/[hree types ofloeal landslide.l (after Coale.l 1970: Fig. 6-17): (a) rockfall; (b) rorafional

landslide (rotarionalshear); (c) rockslide (plane shear).

HYDROGEOLOGY A hydrological divide exists along the southem hills of Rrunat Bet Shemesh, separating the region n i to two drainage sub-basins: (1) a northem sub-basin that

CHAPTER 7: THE GEOLOGY

drains toward NaI,lal Soreq; (2) a southern sub-basin that drains toward Nal,lal ha-Ela. As most ofthe area of Rarnat Bet Shernesh is composed of impervious marls, chalky marls and chalks of the Taqiya Fonnation (measured penneabilities range in the vicinity of 1 0,-5,-1 0,-8) cm/sec), it can be assumed that most of the precipitated water flows above the surface and only the uppennost layers of rock are wetted by seepage of water into the rock mass. A remaining fraction of the accumulated water flows into and through healed and impregnated fractures and joints in the rock, especially in its more chalky zones. As most of the fractures are limited in length and depth, only local zones of perched water are created. These local concentrations of water flowing through an intricate assemblage of fractures are united into larger flows, which emerge as small springs and wet patches along the lower topographical levels of the area, for example in Nal,lal Yannut and alongside the Bet Shemesh-Bet Guvrin road (see also Chapter 1). An even smaller fraction of the water reaches the regional water table at levels close to 50-100+ m asl, or 200-300 m below the existing topography. Flows of water along open impregnated fractures or joints were observed in many excavated ditches during the various construction phases of Rarnat Bet Shemesh. Further evidence for the flow of water within these same fractures is found in the composition of the minerals constituting the impregnation, i.e., calcite and iron oxide, minerals known to precipitate from flowing water through various chemical processes. It should be noted that the depth of the perched flow is limited to a few tens of centimeters above the impervious beds upon which it occurs. This mechanism of flow through fractures toward the lower topography explains the existence of a continuous flow of water in streams such as NaDal

III

Yannu� where cisterns have been built throughout the centuries to capture the water. During the rainy season, small flows of water have been observed along the contact between the nari crust and the marly-chalky rock upon which the nari develops. These flows, together with water flowing upon the surface, were drained into the numerous cisterns excavated in the rock. SOIL

The soil covering the hilly terrain of Ramat Bet Shemesh is essentially limited to depressions in the rock and to locations characterized by geological discontinuities such as landslide zones and open cracks developed through creep. Elsewhere, the soil thickness does not exceed 1 m, and even this accumulated with the assistance of man-made terraces (see Chapter 8). Within the elliptical boundaries of landslides, the soil accumulation can reach 2-3 m, where the darker soil assists in defining with high precision the boundaries of the sliding mass. Such phenomena were observed close to coordinates NIG 1 9845/62425 and 1 9900/62480, as well as in many other locations. When the soil is mixed with crumbled rock fragments, it can reach a thickness of about 5 m. Along the streams and tributaries of Nal,lal Yannut, Nal,lal Zanoal) and Nal)al Yish'i, the soil can reach a thickness of 5 to 8 m. Where fractures have developed in the nari, soil penetrates through the open cracks into the weak zone, filling voids such as caves and open fractures (see Fig. 7.2). Creep observed along slopes includes nari boulders and blocks as well as soil, and sometimes includes a portion of the original rock (marl or chalky marl). This configuration of creeping material containing soil and boulders lends the topography its rough, shattered appearance.

NOTES 1

The area of the planned municipality of Ramat Bet Shemesh was surveyed and researched between 1990 and 1997 by the author on behalf of the Department of Technical Engineering-Design and Planning Division of the Israel Ministry of Construction and Housing, headed by Moshe Sokolovsky. The need for such a survey was amplified by

the severe foundation and structural problems encountered over the past sixty years in the housing projects of the older town of Bet Shemesh, which was developed during the 1 950s-1970s. 2 Then of the Institute of PetroIeurn and Energy of the Israel Ministry of National Infrastructures.

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UZI SALZMAN

REFERENCES

Buchbinder B. 1969. GeologicalMap ofHashephelaRegion, Israel (The Geological Survey ofIsIael, Report OD/li68). Jerusalern. Coates D.F. 1970. RockMechanics Principles. Ottawa. Gvirtzrnan G. and Buchbinder B. 1969. Outcrops a/Neogene

Formation in the Central and Southern Coastal Plain

Hashephela and Be 'er Sheva ' Regions, Israel (Geological Survey ofIsTael Bulletin 50). Jerusalem. Hoek E. and Bray J.W. 1 9 8 1 . Rock Slope Engineering (revised 3rd ed.). London-New York.

CHAPTER 8

THE GEOMORPHOLOGY ELDAD BARZILAY

INTRODUCTION

MORPHOLOGY

This chapter describes the geomorphological setting of Ramat Bet Shemesh and its geo-archaeological implications, with an emphasis on the role of man as a geomorphological agent The scope of the Ramat Bet Shemesh Regional Project presented a unique opportunity to study geo-archaeological topics at a semi-regional level. In addition, such a large-scale study was further necessitated by the fact that the natural features of this rural area would be lost forever following the planned development 1 The focus here will be on the construction of agricultural terraces, clearly the most important of the man-made features affecting the overall ecological balance of the landscape of Ramat Bet Shemesh. Several different aspects of this subject were investigated, principally the origin of the fills within the agricultural terraces, carried out through a detailed soil survey in the region of Ramat Bet Shemesh. The technology of the agricultural terracing in the Ramat Bet Shemesh region was studied in light of modern engineering ill ethods. However, first of all, the overall morphology of the area must be described, while reviewing the closely related topics of the geological setting, nan formation and precipitation properties. Precipitation properties in this area have been measured at the Bet Girnal rain-gauging station since 1 9 1 9. These properties, combined with topographical and soil-association maps, were used as input for a SERS II model (Garti, n.d.), which predicts peak discharge distribution of extreme runoff events. The implications of the results of the model were then compared with the actual check-dam systems located within the wadis of the RamatBet Shemesh area. In addition, the results of a flint provenance survey are reported here.

The Judean Shephelah is an asymmetric synclinorium alongside the Judean anticlinorium . These north­ northeast-south-southwest structural features were apparently created in the Santonian era as part of the Syrian arc of the Levant (Wachs et a!. 1 990). The Shephelah region can be divided into two longitudinal strips, the eastern High Shephelah and the western Low Shephelah. The High Shephelah was formed during the Miocene age, as a result of an uplift of the area, regression of the sea and fonnation of abrasion surfaces, while the Low Shephelah represents a later abrasion surface of Pliocene age (Sneh and Buchbinder 1984). This is the reason for the similar elevation and leveled nature of the summits in the Ramat Bet Shemesh region, situated in the High Shephelah. Most of the area of the municipality of Ramat Bet Shemesh is confined within the Nal,lal Yarmut drainage basin, a tributary of Nal,lal Soreq. The boundaries of the Yarmut watershed are the Nal,lal Zanoal) basin to the east, the Nal)al ha-Ela basin to the south, Nal)al Timna to the west and Nal)al Soreq to the north (see Fig. 1 .4). Nal)al Soreq and Nal)al ha-Ela are part of the pre-Shephelah drainage system that followed the regression of the sea. Nal)al Zanoal), Nal)al Timna and Nal)al Yarmut are younger drainage systems that evolved after the regression of the sea during the Miocene age (Nir 1970:1 85-188). Nal)al Zanoal) is a strike valley that incised perpendicular to the regional gradient in the fringe zone of the High Shephelah (Feldman 1 964), in the contact lineament between the abrasional surface and the Judean Hills. Its northward course is the result of a local northward dip of the small-scale anticlinal structure of the ha-Ela Valley. As a result, the Yarmut drainage basin carne to be disconnected from the Judean Hills.

114

ELDAD BARZILAY

The Yannutdrainage basin can be divided into several sub-basins. The western part of the basin, situated west of the Bet Shemesh-Bet Guvrinroad (Road 38; see Fig. 1 . 4), comprises 1 1 % ofthe area and is characterized by small-scale basins with short, straight gullies, and is not included in the Ramat Bet Shemesh district The eastern part is divided into four small basins with wide flood plains extending westward. These tributaries join the main stream of Nai.lal Yannut running northward and parallel to the Bet Shemesh-Bet Guvrin road, toward Nai.lal Soreq. The two southern tributaries are narrower than the northern ones. The gradients measured along the channel-beds (0.5-2.5°) and the water divides (3_8°) are moderate, while the slopes are steeper (1 3-26°). The Ramat Bet Shemesh region is divided into seven geographical sub-units by the main channels of the drainage system (see Chapter 1). GEOLOGY

Outcrops of the Taqiya Fonnation of Paleocene age, consisting mainly of marl, and of the z,or'a Formation (,Adullam Member) of Lower to Middle Eocene age, consisting mainly of chalk, cover most of the Ramat Bet Shemesh region (see Chapter 1). Conglomerates and alluvial deposits of the Pliocene and Quaternary ages appear on the outskirts of the region (Gvirtzman and Buchbinder 1 969). The topographical setting of the conglomerates is important for the reconstruction ofthe paleo-alluvial system in the Shephelah (Feldman 1964; Gvirtzman and Buchbinder 1 969; Sneh and Buchbinder 1984; Buchbinder, Sneh and Diamant 1986). Flint Provenance Survey

The beds of the chalky 'Adullam Member of the z,or'a Fonnation were an important source of flint for prehistoric cultures. These chalky beds are partly silicified and accompanied by discontinuous flint nodules. However, in most places the 'Adullam chalk is covered by a nari crust that makes it difficult to locate and exploit the em bedded flint Other sources of flint may have been the beds of gray and light brown brecciated flint of the Campanian Meshash Formation exposed along the eastern bank of Nai.lal Zanoal). Secondary sources of flint include conglomerates of Neogene to Quaternary age, or even wadi flint pebbles originating from the Judean Group outcrops that are

incised by Nal)al Soreq, Nal)al ha-Ela and Nal)al Zanoal). A partial study of flint provenance in the Ramat Bet Shemesh region was conducted with Vladimir Zbenovich (1995-1996). In this study, flint samples taken from outcrops of the Meshash Fonnation along the eastern slopes of Nal)al Zanoal) and from outcrops of the Z:or'a Formation west of the Bet Shemesh­ Bet Guvrin road were compared (visually) with flint artifacts derived from Sites 219 (Dagan 1 998a), 238 (Dagan, Zbenovich and Mettens 1998; Zbenovich, in prep.) and other sites described in the prehistory survey (see Chapter 13; Khalaily, Hameiri and Marder 1998). The Meshash flint was most similar to the Neolithic and Chalcolithic artifacts, while Meshash and 'Adullam Member flint was probably the raw material used at Neolithic Site 238 (Zbenovich, in prep.). A number of blades and a core made of 'imported flint' (Kolodny 1 965) were found by Zbenovich at Site 222. These 'imported' flint pebbles are related to a Neogene drainage system that existed before the Dead Sea Rift was fonned and connected the Arab Massif to the Mediterranean Sea. They are found within outcrops of the I:Ia�eva Fonnation in the Negev and the 'Arava (Zilberman 1992). Although there is no evidence that Nal)al Soreq ever transported such pebbles, I:la,:eva Fonnation outcrops are reported around Jerusalem at the headwaters of Nal)al Soreq (Horowitz 1 970) and flint pebbles resembling 'imported' flint were observed in the vicinity of Ramat Ral)el, within a channel that is considered a relict of ancient Nal)al Soreq (Yoav Avni, pers. comm. 1 997). 'Imported' flint pebbles were not found in the Soreq alluvial terraces during the present survey and thus the origin of this flint remains unknown. The Nari Calcareous Crust

The nari crust is one of the major geomorphological agents that shape the landscape of Ramat Bet Shemesh. Nari is a local name for the calcrete calcareous rock that forms a hard crust upon the existing topography of soft calcareous rock (for studies of nari rock, see Blanckenhorn 1 9 1 2; Goldberg 1959; Buchbinder 1969; Gvirzman and Buchbinder 1969; Yaalon and Singer 1 974; Dan 1 977, 1988b; Shaharabani 1 992). The fonnation of the nari crust was probably initiated during the Pleistocene or perhaps even in the late stages of the Plio-Pleistocene, and it is today in a state of

CHAPTER 8: THE GEOMORPHOLOGY

disintegration (Dan 1 988b; 1 992). Calcrete or nari is the final stage of development of the petro-calcic soil horizon, which develops in Mediterranean climatic conditions with a precipitation of 300 to 500 mm per year (Gile, Peterson and Grossman 1966; Dan 1977, 1992; Machette 1 985; Shaharabani 1 992). Yaalon and Singer (1 974) separate the nari into three layers: (a) an uppermost laminar nari; (b) an upper hard nari; (c) a lower soft nari that overlies the bedrock. Nari is important due to its influence on human activities in the Rarnat Bet Shernesh region as well as in Israel as a whole. The upper nari is the hardest quarry rock in the region, therefore it was an important source of building material (see Site 237. 1 [Abd Rabu 1998] and Site 244.2 [Shabi 1998]). Agricultural installations, such as treading floors and collection vats, were hewn into it, and it served as the roof for caves and water reservoirs that were cut through it into the soft bedrock (Site 246. 1 ; see Milevski 1998, in prep.). Stages ofNari Formation The alteration process of weak calcareous rocks (such as marl or soft chalk) involves the formation of calcareous pale rendzina soils on the surface. Some of the calcium carbonate from the upper layer of the soil is washed down by rainwater and is precipitated into the lower layer, which eventually becomes a calcareous horizon. At this time, the voids within the calcareous horizon are filled with carbonate (Dan 1977; Machette 1985). This process slows water penetration into this horizon so most of the precipitation activity occurs in the uppermost layer, which is re-crystallized, becoming harder and less permeable (upper nari). As a result, a subsurface flow of water occurs on top of the upper calcareous horizon, eventually fonning a laminar layer. The laminar layer develops during this phase as a biological soil crust growing on the surface in places where the soil is eroded (Shaharabani 1 992). The dissolution and re-crystallization processes create forces that defonn the upper nan crust. As a result, the upper nan separates from the lower nan and creates domes, 1 0-15 m in diameter. The center of these domes is elevated up to 1 m (Dan H. Yaalon, pers. comm. 1 996). Fissures appear between the domes creating a shallow karst system. Brown rendzina soils develop in the lower areas of this micro-topography, and fine earth penetrates and fills the karst system .

115

Outcrops ofNari in Ramat Bet Shemesh The durable nari crust formed just below an ancient surface at the interface between the soil and the bedrock. It fossilized the landscape and caused massive erosion of the soil mantle. The main stages of the drainage-network fonnation preceded the appearance of the nari. The drainage system was filled with fine colluvial-alluvial sediments washed down from the slopes, reaching the present depth of 5 to 8 m. The width and depth ofthese channels are much larger than the present-day active wadis. According to Dan (1962; 1977), the process of nari disintegration is initiated by undercutting at the base of the slope. Later on, blocks of nari disintegrate and creep down the slope. A low cliff is formed along the nari detachment line, a 1-3 m high nari step that occurs just above the wadi bed. Clusters of dislocated nari blocks are found on the lower slopes. The process continues up the slope and is accelerated along the small tributary gullies that cut into the exposed bedrock. These small elongated depressions in the landscape are widened and occasionally join, revealing the soft rock along the surface of the slope and leaving islands of nari on the lower part of the slope. The disintegration is faster and more pronounced on the southern slopes as compared to the northern ones, which are more densely vegetated (Dan 1 962). The nari crust in the Ramat Bet Shemesh region has been largely eroded from the slopes in the northern part of the region and continuous nan is found mainly on the summits and the upper slopes. Areas that are still covered by nan crust are denoted by calcareous clayey brown rendzina soil (Fig. 8 . 1 : Soil Type 12). The gravelly nature of the soils in Ram at Bet Shemesh results from the disintegration of nari and chalk. The size of the dislocated nari blocks is a result of the fissures associated with the final stages of nan formation. Once a nan block is dislocated, these cracks widen and release some of the pressure holding the nari blocks together. Agricultural installations cut into the nan enable us to evaluate the rate of movement of the nari blocks. Many collection vats excavated in Ramat Bet Shemesh exhibit open crevices and cracks that have ruptured them . In most cases the cracks are just a few centimeters wide. Hence, the initial stages of nan-block movements are very slow. On the other hand, the landslides that are common in the region cause rapid movement of the blocks (see Chapter 7).

116

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CHAPTER 10 THE ECOLOGICAL SURVEY

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CHAPTER 10 THE ECOLOGICAL SURVEY

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