QUATERNARY RESEARCH 21, 1 l7- 120 (1984) -

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Reply to Comments by Ann P. El-Moslim

1 welcome the opportunity provided by El-Moslimany to open discussion on some of the issues raised in my paper, and also to clarify one or two items which were ap- parently misunderstood. It is useful to point out initially that her critique comes from the perspective of palynology, since it may therefore appear to the outside observer that this discussion represents a conflict be- tween data from geomorphology on the one hand, and palaeobotany on the other. In fact, this is not the case; there is 110 major conflict between these two sets of data in the Near East, at least as far as orthodox interpretations are concerned. El-Moslim- any’s pollen evidence actually mostly rep- resents a reappraisal of pollen diagrams produced by other palynologists, notably van Zeist and Bottema, although she fails to mention this important fact in her com- ments. At the time of writing I do not have access to her Ph.D. dissertation, but in a recently published paper (El-Moslimany, 1982) she used the ChenopodiaceaelArte- misia ratio, rather than the more traditional AP/NAP ratio, as a moisture index. This led her to interpret vegetation history in a way at variance with that proposed by the original investigators. In the case of the pleniglacial at Zeribar in western Iran, van Zeist and Bottema (1977) suggested that the consistently low (4%) levels of arboreal pollen (AP) resulted from a combination of cold and aridity, whereas El-Moslimany (1982) reinterpreted these data to indicate cold but moist conditions. It is not for me to judge the relative merits of the two in- terpretations, but I think it important for the observer to be aware that El-Moslim- any’s account of Near East vegetation his- tory is not the only, nor even the conven- tional, one.

I shall now turn to more specific com-

ments, dealing with he in turn.

1. El-Moslimany a claim that precipitation was reduced duilng the Pleistocene, specifically at the time of the last high water level in palaeolake Konya. In fact, my proposal was restricted to one point in time, namely ca. 17,000 yr B.P., when the lake level was falling dra- matically from a maximum to a minimum elevation, indicating a strongly negative water balance. As this regression appears to have been synchronous with tempera- tures low enough to cause ice wedges to form, I was able to conclude that precipi- tation could not have been as high as it is at present. I did not, nor would I wish to, make the claim that that precipitation was reduced throughout the entire late Pleisto- cene. It is possible that precipitation values were slightly above those of today at other times, such as in the early part of Konya II (23,000-21,000 yr B.P.) or during Konya III (12,000- 11,000 yr B.P.). However, the fact remains that the large surface area:depth ratio of palaeolake Konya has made its water balance much more sensitive to changes in evaporation (and therefore to temperatures plus cloud cover, etc.) than to changes in precipitation.

2. I am reported as concluding that the effects of the so-called “Neolithic pluvial” (ca. lO,OOO-5000 yr B.P.) were unfelt in the Middle East. I said no such thing, of course. Rather, the point I wished to make is that by taking a single, and therefore in- ternally compatible, data set (viz., water- level fluctuations in hydrologically closed lakes) it is clear that there was a spatial contrast during the early Holocene between the northern and southern parts of the Near East. Whereas the latter contained high water levels in lake basins which are now

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118 LETTERS TO ,----- ------ l’HJ5 EDl’I‘UK

FIG. 1. Moisture levels in the Near East 9000-8000 yr B.P., compared to those at the present day. Closed triangles = pollen, more humid; open triangles = pollen, drier (data from van Zeist and Bottema, 1982, Fig. 14). Closed circles = higher lake levels; open circles = lower lake levels (data from Roberts, 1982. Jubbah, shown in parentheses, has only a single Ho- locene t4C date of 6685 yr BP.). Note that peat de- posits at the head of the Arabo-Persian Gulf reported by El-Moslimany lie at the northern margin of the zone of enhanced summer rainfall.

dry (e.g., Mundafan; McClure, 1976), the former did not. The most northerly lakes to experience a significant increase in water level were Jubbah in Arabia (28”N) and Siwa in Egypt (29”N) (Garrard ef al., 1981; Hassan, 1978) (Fig. 1). A south-to-north moisture gradient is precisely what might be expected if the source of increased pre- cipitation were summer monsoonal-type rainfall, as Kutzbach (1981) suggests and El-Moslimany appears to accept. But did this poleward shift in tropical rains cause the northern part of the Near East to be- come drier or moister than at present? Arid- ity would be predicted if there were either a northward displacement of westerly depression tracks over the Mediterranean, or a strengthened dry, northerly air flow west of the south Asian monsoon (Kutz- bath, 1983, p. 380); humidity might be ex- pected if there were greater interaction be- tween midlatitude and tropical air masses

(cf. the Saharan disturbances described by Nicholson and Flohn, 1980, p. 330). There are relatively few well-dated early Holo- cene lake-level curves for the northern Near East which can be used to test the two alternatives, but several of them show water levels lower than at present. The southern basin of the Dead Sea (31”N) dried up during the early Holocene (bracketing dates 9850 and ca. 5500 yr B.P. ; Neev and Emery, 1967), as did Lake Urmia in Iran (38”N; K. Kelts, pers. comm., 1982), while varve-dated sediment cores from Lake Van (38”30’N) record a major fall in lake level between 10,000 and 6000 yr BP (Degens and Kurtman, 1978). On the other hand, with so few sites available it is natural, as El-Moslimany suggests, to turn to the early Holocene pollen record for clarification. From this she draws the conclusion that many Near Eastern forests reached their greatest extent around 9000-8000 yr BP Yet, in the most recently published account of East Mediterranean vegetation history (van Zeist and Bottema, 1982) every pollen diagram except one (Ghab, northwest Syria) recorded a lower proportion of tree pollen for that time period than for the present day. Van Zeist and Bottema con- cluded that “dryness prevented a more rapid expansion of trees . . . in the early Holocene” (western Iran, southeast and central Turkey, pp. 278-279), that “after 10,000 yr B.P. open vegetations gained ter- rain at the expense of the oak forest” (southern Levant, p. 283), and that even in better-watered areas, deficiency of mois- ture altered forest composition (Greece and southwest Turkey, p. 287). The bulk of the palynological evidence therefore agrees with lake-level fluctuations by indicating greater aridity than at present north of 30”N, while the southern part of the Near East was experiencing greater humdity (Fig. 1).

3. El-Moslimany criticizes my sugges- tion that the existence of high-level lakes in both the northern Near East and the Amer- ican Southwest disguises a palaeoclimatic

LETTERS TO THE EDITOR 119

contrast between the two regions during the late Pleistocene. This is an interesting sub- ject, and one which demands more detailed comparison than I was able to offer. The present-day differences in seasonality of rainfall and vegetation cover pointed out by El-Moslimany are among a number of fac- tors which should be considered in such a comparison. One advantage of a compara- tive approach is that it may help to resolve internal disagreements over late Pleisto- cene climates, to which both regions have been subject (e.g., Galloway, 1983). My ini- tial impression has been that a comparison confirms what may be considered as the mainstream view in each region; that is, one of an increase in effective moisture in the American Southwest, but one of mois- ture reduction in the highland zone of the Near East. At the very least, El-Moslimany must agree with me that there was a marked contrast in late Pleistocene vegetation in the two regions, whatever climatic inter- pretation should be placed upon it. In the Near East, high lake levels are associated with open vegetation at Zeribar, Ioannina in northwest Greece (Bottema, 1974; Higgs, 1978), and in south-central Turkey. As El-Moslimany correctly observes, the oldest pollen levels from Akgol, Konya, ap- pear to be younger than the last phase of high water levels (=Konya II; 23,000- 17,000 yr B.P.). On the other hand, the nearest 14C-dated pollen site to include that time period (Karamik; van Zeist et al., 1975) shows no evidence whatever for forest vegetation. Equally low levels of AP are recorded in pollen spectra from white marl in the Konya basin, which probably date to the later stages of Konya II (de Meester, 1971, p. lg). As this also applies to pollen diagrams from Greece, all of which lie at elevations below 500 m, it is not possible to explain the absence of forest in terms of specifically montane conditions.

I would add finally that El-Moslimany seems to fall into the same trap which has snared so many authors, that of trying to find a single palaeoclimatic sequence which

can be applied to the whole of the Near Eastern region. Such a goal is illusory, as I hope is illustrated by the intraregional con- trast for the early Holocene shown in Fig. 1, in which northern areas appear to have become drier as southern ones became moister. Let me therefore repeat the con- cluding statement of my original paper: the Near Eastern climatic record is not homo- geneous from one place to another. This is furthermore likely to be true for other parts of the subtropics, such as northern-Mexico, and may be explained in large part by lati- tudinal shifts of features of the general at- mospheric circulation.

REFERENCES Bottema, S. (1974). “Late Quaternary Vegetation

History of Northwestern Greece.” Groningen. Degens, E. T., and Kurtman, E (Eds.) (1978). “The

geology of Lake Van.” MTA Institute Publ. No. 169, Ankara.

de Meester, T. (1971). “Highly Calcareous Lacustrine Soils of the Great Konya Basin, Turkey.” PUDOC, Wageningen.

El-Moslimany, A. P. (1982). The Late Quatemary veg- etational history of the Zagros and Taurus moun- tains in the regions of Lake Mirabad, Lake Zeribar and Lake Van-A reappraisal. In “Palaeoclimates, Palaeoenvironments and Human communities in the Eastern Mediterranean Region in Later Prehistory” (J. L. Bintliff and W. van Zeist, Eds.), pp. 343-351. Brit. Archaeological Reports, Int. Ser. 133, Oxford.

Galloway, R. W. (1983). Full-glacial southwestern United States: Mild and wet or cold and dry? f&a- ternary Research 19, 236-248.

Garrard, A. N., Harvey, C. P D., and Switzur, V. R. (1981). Environment and settlement during the Upper Pleistocene and Holocene at Jubbah in the Great Nefud, Northern Arabia. At/al 5, 137-148.

Hassan, F. A. (1978). Archaeological explorations of the Siwa oasis region, Egypt. Current Anthropology 19, 146- 148.

Higgs, E. (1978). Environmental changes in Northern Greece. In “The Environmental History of the Near and Middle East Since the Last Ice Age.” (W. C. Brice, Ed.), pp. 41-49. Academic Press, London/ New York.

Kutzbach, J. (1981). Monsoon climate of the early Ho- locene: Climate experiment with the Earth’s orbital parameters for 9000 years ago. Science 214, 59-61.

Kutzbach, J. (1983). Monsoon rains of the Late Pleis- tocene and Early Holocene: Patterns, intensity and possible causes of changes. In “Variations in the

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Global Water Budget” (A. Street-Perrott, M. Beran. and R. Ratcliffe, Eds.), pp. 371-389. Reidel. Dor- drecht.

McClure, H. A. (1976). Radiocarbon chronology of late Quaternary lakes in the Arabian desert. Nature (London) 263, 755-756.

Neev, D., and Emery, K. 0. (1967). The Dead Sea. Bulletin of the Geological Survey of Israel 41, 1-147.

Nicholson, S. E., and Flohn, H. (1980). African en- vironmental and climatic changes and the general atmospheric circulation in Late Pleistocene and Ho- locene. Climatic Change 2, 313-348.

Roberts, N. (1982). Lake levels as an indicator of Near Eastern palaeoclimates: A preliminary appraisal. In “Palaeoclimates, Palaeoenvironments and Human Communities in the Eastern Mediterranean Region in Later Prehistory” (J. L. Bintliff and W. van Zeist, Eds.), pp. 235-267, Brit. Archaeological Reports, Int. Ser. 133, Oxford.

van Zeist, W., and Bottema, S. (1977). Palynological investigations in western Iran. Palaeohistoria 19, 19-83.

van Zeist, W., and Bottema, S. (1982). Vegetational history of the eastern Mediterranean and the Near East during the last 20,000 years. In “Palaeocli- mates, Palaeoenvironments and Human Communi- ties in the Eastern Mediterranean Region in Later Prehistory” (J. L. Bintliff and W. van Zeist, Eds.), pp. 277-321. Brit. Archaeological Reports, Int. Ser. 133, Oxford.

van Zeist, W., Woldring, H., and Stapert, D. (1975). Late Quatemary vegetation and climate of south- western Turkey. Palaeohistoria 17, 53-143.

NEIL ROBERTS Department of Geography Loughborough University

Leicestershire, United Kingdom