Journal of Coastal Research Fort Lauderdale, Florida Summer 1992
Possible Types of Coastal Evolution Associated with the Expected Rise of the World's Sea Level Caused by the "Greenhouse Effect"
Yuri S. Dolotov
Department of Oceanology AtmosphericPhysics and Geography USSR Academy of Sciences Moscow, USSR
ABSTRACT_•••••••••••••••••_
DOLOTOV. Y.S., 1992. Possible types of coastal evolution associated with the expected rise of the world's sealevel caused by the "greenhouse effect," Journal of Coastal Research, 8(3),719-726. Fort Lauderdale ,tlI111111:.
ADDITIONAL INDEX WORDS: Sea-level rise, sedimentation, coastal chnnge
INTRODUCTION level rise contribute to a manifestation of shore erosion, the retreat of the shoreline and the land The questions associated with coastal evolution ward displacement of the entire beach profile that under conditions of sea-level rise have great im is well known from the early works of GILHgRT portance at the present time because of the (1885) and ,JOHNSON (1919), Later efforts include "greenhouse effect" problem, the forecast of ap those of ZENKOVICH (195f>. 1957, 19(2), hJNIN preciable warming of the climate because of the (1955), FISCHgR (1961), BIWUN 09(2), SCHWARTZ accumulation of carbon dioxide and other indus (J967). SANDERS and KUMAR (1975). and SWIFT trial products of combustion in the earth's at and MOSU1W (1982) along with Dor.orov et al. mosphere. This warming is expected to cause a 09(4) and DOLOTOV (J 97l). Coastal flooding leads melting of existing glacial ice which will subse to an acceleration of the entire range of shore quently lead to a rise in the world's sea level. erosional processes, to the formation of active clitfs A forecast of the effects of sea-level rise on the and to other erosional relief forms. The erosional evolution of different coastal types, especially on responses may differ considerably because of sta the depositional coasts (the most important for bility of the rock formations relative to the pro human activity), can be based on the existing data cesses of cliff recession and because of the char regarding the evolution of the world's shoreline acter of the features found at the base of the cliff. during the Holocene transgression. Much infor In the literature there is a widely-held opinion mation can be derived from the specific charac that under conditions of sea-level rise, a shoreline teristics of the Azov-Black Sea basin, see the ini composed of unconsolidated sediment and with tialdetailed descriptions by N EVESSKY (1958, 19[)9, an equilibrium profile will develop in accordance 1960, 19(1). with the "Bruun Rule" (BRUUN, 1962; SCHWARTZ, In general, the conditions associated with sea- 19(7). According to the Bruun Rule, the sediment erodes in the upper part of the beach profile and 91115 received and a('ccplt'd in revision 2Y Noncmber 1~91 accretion occurs on the lower part of the sub- 720 Dolotov
------:--:-,~.-~ ~ " . ••• mud '..-r.~-=:,-. ~:.~.f;,.
sand discordant I contact
1 _.:.: . ~: . lagoon -.-.~•• : ••• : ~-:- ••
mud washed sand
.0·· ...... ~.. ' ."
••••.~.. 1 [
Figure 1. Relief-forming and depositional processes on the shallow coast under conditions of sea-level rise: (a) transgression and burial by finer sediment; (b) displacement of the depositions form, accompanied by erosion on its seaward margin; (c) long-term and continuous shoreline progradation; 1, 2, ~l the positions of sea-level and resulting profile in the course of three stages of successive sea -level rise.
aqueous beach profile. Another possibility is sug the flooding of the land. As a result, the volume gested here, following views expressed by of sediment supplied to the upper part of the ZENKOVICH (962), that at locations of gently-in submarine shore slope is not sufficient to insure clined submerging coastal lands (with slopes gen the progradation of the shoreline. Sediment that tler than slopes of the submarine shore equilib might be supplied to the shoreline by erosion of rium profile) the sediment that is mobilized by cliffs is very limited because accelerated cliff ero wave action is moved shoreward. This sediment sion can only occur in easily eroded formations is transported to accumulate in the upper part of because of the very short time of exposure of cliffs the profile. There is evidence in the natural land to the erosive action of waves (DOLOTOV, 1989). scape to support the possibility of this type of The rapid sea-level rise causes an elevation of the coastal evolution. base level of the streams leading to the sea and that in turn leads to the reduction of the current SHALLOW-WATER SEA COASTS velocity and the quantity of transported sediment It has been presented (DOLOTOV, 1962, 1971, that enters the estuaries and eventually contrib 1989) that under conditions of sea-level rise on utes to the depositional coastal landforms. shallow-water depositional coasts, there are three In the case of shallow-water sea coasts, the in possible types of shoreline evolution. undation (accompanied by some initial erosion of the surface) and the subsequent burying (pres The Inundation and Preservation of Depositional ervation) of existing depositional forms (Figure Forms l a) on the seaward portion of the profile, lower In the course of rapid flooding of the coast, the than the fair-weather wave base position, are typ rearrangement of the profile by adaptation of the ical (DOLOTOV, 1962, 1971). Forms such as barriers hydrodynamic factors to the conditions of depth are often created in the zone of intensive wave changes (thereby insuring the possibility of sed action. They are capped by deep-sea fine sedi iment movement landward on gently-inclined ment. The formation of these features corre bottom profiles) "lags behind" in comparison with sponds to the case of "in place drowning" as iden-
.Iournal of Coastal Research, Vol. 8, No.3, 1992 J IGU 1989 Portugal Field Symposium 721 tified by GILBERT (1885) toward the end of the shoreline such as spits which are adjacent to ero past century and to the situation recently pre sional coastal areas is caused by the accelerated sented by BUSCH (1974) under conditions when retreat of the cliffs which brings the adjoining the rate of sediment supply is lower than the rate depositional forms inland with them (ZENKOVICH, of relative submergence caused by sea-level rise. 1946). An example of this association is on the The incorporation of coarser sedimentary lay northern coast of the Sea of Azov. The evidence ers within muddy units of Holocene age has ap consists of the narrowing of the spits in their mid parently been caused by a similar developmental dle sections, the truncation of the older beach situation and has been noticed by many research ridges by the eroding recent shoreline, partial ero ers in many different areas: in the Sea of Azov sion of the lagoonal muddy sedimentary strata, (LEONTlEV and LEONTIEV, 1956; DOLOTOV, 1962), and the existence of ancient beach sediments for theBlack Sea (NEVESSKY, 1958,1959,1960,1961), a great distance from the modern shoreline and the Gulf of Mexico (FISK, 1959), the Bering Sea the presence of this sediment blanket in a sea (SHCHERBAKOV, 1961), the Sea of Japan (MED ward-thinning wedge (DOLOTOV, 1962). The rate VEDEV et al., 1961), the Sea of Okhotsk (VLADI of the displacement of the external margin of the MIROV, 1959), the Mediterranean Sea (VAN spit depends on the amount of the sediments be STRAATEN, 1959), and on the U.S.A. Atlantic coast ing supplied from the erosion of the adjacent cliff. (KUMAR and SANDERS, 1976). As sea level rises, And that, in turn, is related to the composition the barrier remains in place as the adjoining bay of the rock formations, the height of the cliffs, the deepens and widens landward. Afterward, the length of the erosional shoreline, and by the wave shoreline retreats in stepwise fashion to another intensity (DOLOTOV, 1989). landward location as a product of the inundation, Under conditions of sufficiently rapid sea-level as described by GILBERT (1885). rise, such displacement occurs at the depositional barriers that are not directly associated with the Displacement of Depositional Form Accompanied changes in their adjacent cliffed coasts. For ex by Erosion of Its Seaward Margin ample, such an evolution of barrier islands has The second possible shoreline type that can oc been characterized for the separate stages of the curon shallow-water depositional coasts is asso geologic history of the coast of the Sea of Azov ciatedwith appreciable erosion of the deposition (DOLOTOV, 1962) and the Caspian Sea (DOLOTOV, al forms and displacement of these forms with 1958), as well as on the U.S.A. Atlantic coast (RYER, flooding (Figure Ib), This situation would take 1977; LEATHERMAN, 1983). Such a displacement place under three conditions: (1) sufficiently rapid of barrier islands evidently could take place dur sea-level rise, (2) a slow rate of displacement, and ing the initial submarine stages of their evolution (3) a total exhaustion of the sediment supply (ofshallow-water sand banks) as well as after their (DoLOTov, 1989). appearance above sea-level (DOLOTOV, 1958). Under conditions of sufficiently rapid sea-level Under conditions of sufficiently rapid sea-level rise, the major relief-forming process is the coastal rise, the sediment supply is continuously increas flooding and erosional processes that are greater ing because of abundant marine erosion and be than the rate of landward transfers of sediment. cause of a considerable sediment supply being Thissituation occurs despite the greater intensity provided by fluvial processes (under conditions of of the erosional processes on the adjoining cliff less severe coastal flooding of river mouths and because of the longer time of wave-action on the estuaries than in the first evolution type). How same sea level position compared to the previous ever, the amount of sediment that is supplied to type. For this reason, the volume of sediment sup the downdrift margins of depositional forms does plied by cliff erosion to the seaward margin of the not compensate for the volume of sediment that subaerialdepositional form and accumulated there is transferred to the underwater component be canbe less than the volume under the previously cause of flooding. For this reason, the dimensions eroded condition of land inundation (DOLOTOV, of the depositional forms during the Holocene 1971). Such a situation has been ascribed, for ex tend to decrease and some are totally lost ample, for the Holocene geomorphologic history (DOLOTOV, 1971). ofthe coasts of the Bering Sea (IONIN, 1955) and Because of the total increase of the sediment the Sea of Okhotsk (VLADIMIROV, 1958). supply in the coastal area, the bottom surface Displacement of depositional forms at the must grow upward, but it is not appreciable be-
.lournal of Coastal Research, Vol. 8, No.3, 1992 722 Dolotov cause the rapid change of the shoreline position Long-Term Continuous Shoreline Progradation leads to the stretching of the sediment blanket over the great extent of the profile (DOLOTOV, The third type of shallow-water coastal evolu 1971). The existence of thin sedimentary strata t.ion (Figure lc) is characterized by the long term in the present environment represents the former sediment accretion and the continuing seaward depositional features and the extensive erosion of coastal progradation (DOLOTOV, 1989)_ It takes the previous forms. They have been described in place when the volume of supplied sediment ex the coastal zone of the Black Sea (NEVESSKY, 1958), ceeds the volume of unconsolidated material that and the Sea of Okhotsk and the Bering Sea becomes flooded in the course of the sea-level rise. (SHCHERBAKOV, 1983). The formation of the thin Such a coastal evolution type is typical during the residual sand blanket accompanied by the appre slowing down of sea-level rise in the presence of ciable bottom erosion (or by shoreface retreat) has abundant sediment reserves in the coastal area. been noticed on the U.S.A. Atlantic coast (Swn-r, During t.hat time, the maximum rearrangement 1976; Swwret al.; 1973; STUBBLEFIELD et 01.; 19B:5). of the submarine shore slope occurs (DOLOTOV, It is necessary to note that the sediment blanket 1971). It is accompanied by the most intensive often has been interrupted and that a lag cobble sediment. supply shoreward because, according to pavement has been observed (WALKEH and ZENKOVICH (1957), during the slower rate of sea THOMPSON, 1968). This type of coastal evolution level rise the profile rearrangement is more in can be considered to be a "discontinuous depo tensive. LEONTIEV (1961) and NEVESSKY (1961) sitional transgression" type as described by noticed that. at these times the maximum coast CURRAY (1964). line progradation is achieved. Under conditions Under conditions of a slow sea-level rise when of minor land flooding, the rearrangement causes sediment reserves are insufficient and their re a transfer of the sediment and for this reason, the quired replenishment from external sources is not relatively small flooded area of the depositional provided, the displacement of the margins of the forms becomes less than the area that is added as depositional forms landward (accompanied by a result of t.he sediment transfer from the sea erosion) is not caused by the landward retreat of bottom shoreward and its accretion t.o t.he sub the nearby cliffs. It is caused by the sediment aerial component (DOLOTOV, ]971). The charac deficiency that results from the slowing down of teristics of this type of coastal evolution is similar the shore erosion processes and therefore the re to t.he "depositional transgression" type described duction of the supply of sediment available for by ClilmA Y (1964). transport and deposition (DOLOTOV, 1971). The One of the examples of a depositional trans accelerating erosion of the depositional forms, such gressive coast is on the nort.hern coast of the Sea as at the basal portion of spits, sometimes leads of Azov. Because of the slowing down of the sea to their transformation into detached features. as level rise, as determined in 1959 (DOLOTOV, 1962), has been described for the Black Sea (Z~;NKOVWH. the rate of cliff recession has become appreciably J95:Jl. reduced. A wide beach has developed and it has Depositional forms can experience displace built out over an entire spit, including the part ment accompanied by erosion of the margins of attached to the cliff where beach erosion occurred the forms that is not caused by the slowing down earlier (accompanied by truncation of beach ridg of the sea-level rise (DOLOTOV, 1971). This may es). The same evolution type has been described be explained simply by the exhaustion of the sed for the Arabat "arrow", a long barrier island on iment reserves in the offshore zone that occurs the Crimea Peninsula, in that time period. Sea during the profile rearrangement and shoreward ward progradation of the barrier islands as well sediment movement during the sea-level change. as increases in height and volume have also been It can take place because of insufficient replen described for the U.S.A. Atlantic coast (PSUTY, ishment of the local sediment. reserves through J ~B()). alongshore drift.lt can be an area with inadequate Shore progradation is especially characteristic sediment supply in the first place. Under such under conditions of a continuing supply of sedi conditions, the inundation is the dominent mor ment from the large rivers because of the reduc phological process covering profile rearrange tion in t he rate of base level rise (DOLOTOV, 1971). ment, accompanied by transfer of some of the In the Holocene period. it has been described for sediment landward. the region of the Rhone delta (vAN STRAATEN,
Journal of Coastal Research. Vol. H, No. :1, 1992 IGU 1989 Portugal Field Symposium 723
retreating shoreline
beach _ / ridges :.: ~-=.::- ~~? ~
Figure 2. Relief-forming and depositional processes on the deep-sea coast under conditions of sea-level rise: (a) sediments supplied bymarine erosion; (b) sediments supplied by fluvial source. Legend shown on Figure 1.
1959),on the Mexican coast (CURRAY and MOORE, positional form). The final result of the two op 1964), and on the coast of western Kamchatka posite tendencies will determine the evolution type (ZENKOVICH and VLADlMlROV, 1951). (DOLOTOV, 1989). Under conditions of rapid sea Under conditions of the slowing down of the level rise, the retreat of the seaward margin of the rate of sea-level rise and the availability of sedi depositional form may be traced over its entire ment, the barriers experience coastal prograda extent. tion and an increase in height (GILBERT, 1885; On the deep-sea coast under conditions of sea ZENKOVICH, 1957; DILLON, 1970; RAMPINO and level rise, the displacement of the seaward margin SANDERS, 1980; and LEATHERMAN, 198:3). In such of the depositional form is caused mainly by the conditions on the western part of the Sea of Azov, rate of cliff recession due to margin erosion (Fig LEONTIEV and LEONTlEV (1956) have shown that ure 2a). For this reason, the rearrangement caused a chain of separate islets was transformed into a by the accelerated cliff retreat reaches its maxi united subaerial barrier (Arabat "arrow"). The mum extent at depositional forms which are ad same phenomenon has been noticed on the jacent to promontories (such as spits). Chuckchee Sea coast (DANILOV et al., 1980). When the rate of sea-level rise is reduced, the cliff erosion usually slows down also and leads to DEEP SEA COASTS a sediment deficiency at the seaward margin of On deep-water coasts, in general, the deposi the depositional forms and to the reduction of tional forms that are composed of sediment de their area. rived from the erosion of cliffs due to the accel Under conditions of a fluvial sediment source, erated shore erosion processes caused by sea-level it is possible that the area of depositional forms rise must receive a significant amount of sedi at the deep-sea coast may increase as sea-level ment. rises (Figure 2b, left). However, the reduction of The evolutionary character of every shore de the alluvial sediment delivery to the coast is usual positional feature is the product of two opposing because of river mouth flooding (DOLOTOV et al.; factors: (1) the rate of sea-level rise (with a ten 1964). It leads to the inland retreat of the shore dency to flooding of the accumulation form, to the line (Figure 2b, right). retreat of its margin landward, and to the reduc tion of its area), and (2) the rate of sediment CONCLUSION availability (with a tendency to coastal progra In general, the most important factors that will dation and to the increase of the area of the de- cause the development of the different charac-
Journal of Coastal Research, Vol. 8, No.3, 1992 724 Dolotov teristics of coastal evolution types during the an riers formation. Oceanology, 20, 1063-1069 (in Rus ticipated worldwide sea-level rise will be: (1) the sian, English summary). rate of sea-level rise; (2) the nature of the relief DILLON, W.P., 1970. Submergence effects on a Rhode Island barrier and lagoon and inferences on migration forming environmental dynamics (the hydrody of barriers. Journal of Geology, 78,94-103. namic factors); and (:3) the amount of sediment DOLOTOV, Y.S., 1958. Processes of accretion and coast available (the reserve and the conditions for re line progradation on the shallow-water coast under plenishment). conditions of its relative emergence. Transactions of the USSR Academy of Science, Institute of Ocean The rate of sea-level rise determines the du olugy, 1, 52-58 (in Russian). ration and therefore the total intensity of the hy DOL(Yrov, Y.S., 1962. On the evolution of the shallow drodynamic processes. The nature of the envi water coasts during the modern transgression of the ronmental dynamics determines the magnitude Azov-Black sea basin. Oceanolot;y, 2, 278-283 (in (depth) of the reworking of the sedimentary strata Russian). DOLOTOV, Y.S.; IONIN, A.S.; KAPLIN, P.A., and MED or the rate of its increase in thickness under the VElmv, V.S., 1964. Relative sea-level oscillations and influence of wave and currents. In the coastal ar its influence on sea -shore evolution. In: Theoretical eas, the volume of the mobile unconsolidated ma Questions of Sea Shore Dynamics. Moscow: Nauka, terial will dictate the manner of using the ambient 43-52 (in Russian, English summary). Dot.orov, Y.S., 1971. On the evolution of the shallow hydrodynamic energy and will lead to either the water coast under conditions of different rate of its seaward loss of sediment or the landward gain. relative submergence. In: New studies of Sea-shore As shown above, sea-level rise does not always Processes. Moscow: Nauka, 16-21 (in Russian). lead to shore erosion and retreat. Therefore, the DOLoTov, Y.S., 1989. Dynamic Relief-forming and De- I widespread beach erosion of the present may not positional Sedimentary Environments in Nearshore [. Marine area. Moscow: Nauka, 269p. (in Russian, En be due only to the rise of sea level. Marine erosion glish summary). may often be caused by local human activity; for FISCHER, A. G., 1961. Stratigraphic record of transgress- I example, by the artificial regulation of river run ing seas in light of sedimentation on Atlantic coast of off, by sand mining of the beach material, and by New Jersey. Bulletin American Asociation Petro- leum Geologists, 45, 1656-1665. • the building of a variety of shoreline structures. FISK, H.N., 1959. Padre Island and Laguna Madre flats, , Predictions of the rates of possible future sea coastal South Texas, II Coastal Geography Confer- ! level changes for the near term, as proposed by eneI', Washington, D.C.: Coastal Studies Institute, HOFFMAN (1984) to average some centimeters per Louisiana State University, pp. 103-151. year, are comparable to the rates of rise during Gn,BERT, G.K., 1885. The topographic features of lake shores. V. Annual Report U.S. Geological Survey, stages of the Holocene. Thus, it is suggested that 1883-1884, Washington, D.C.: pp. 69-123. future development of the shallow-water coasts HOFFMAN, J. S., 1984. Estimates of future sea level rise. probably should follow the second and third In: BARTH, M. C. and TITUS, J.G. (eds.), Greenhouse coastal evolutionary types described above. Fore Effect and Sea Level Rise. New York: Van Nostrand Reinhold, pp. 79-103. casts of the particular evolutionary model must .JOHNSON, D.W., 1919. Shore Processes and Shoreline be based primarily on the estimates of the sedi Development. New York: Wiley, 584p. ment budget in the specific area. IONIN, A.S., 1955. New data on the vertical tectonic motions of sea shores. Transactions of the USSR LITERATURE CITED Academy of Science, Institute of Oceanology, 13,40 51 (in Russian). BRUUN, P., 1962. Sea-level rise as a cause of shore ero KUMAR, N. and SANDF.Il.S, J.E., 1976. Characteristics of sion. Journal of Waterways and Harbors. 88, 117 shoreface storm deposits: modern and ancient ex 130. amples. Journal of Sedimentary Petrology, 46, 145 BUSCH, D.A., 1974. Stratigraphic Traps in Sand 162. stones-Exploration Techniques. American Associ LEATHF.RMAN, S.P., 1983. Barrier island evolution in re ation Petroleum Geologists, Memoir 21, 190p. sponse to sea level rise: a discussion. Journal of Sed CURRAY, .J.R, 1964. Transgressions and regressions. In: imentary Petrology, 53, 1026-1031. MILLER, RL., (ed.), Papers in Marine Geology. Shep LIWNTIEV, V.K. and LEONTJEv, O.K., 1956. Principal ard Commemorative Volume. New York: Macmillan, peculiarities of the Sivash lagoon geomorphology. pp. 175-203. Vestnic of the Moscow University, Series of Biology, CIJRRAY, J.R and MOORE, D.G., 1964. Holocene regres Soil Science, Geology and Geography, 2, 185-194 (in sive littoral sand, Costa deNayarit, Mexico. In: VAN Russian). STRAATEN, L.M..J.U. (ed.), Deltaic and Shallow Ma L~;ON'I'lEV, O.K., 1961. History of the Kara-Bogaz-Gcl rine Deposits. Amsterdam: Elsevier, pp. 76-82. Bay coast formation. Transactions of the USSR DANILOV, I.D.; NEDESHEVA, G.N., and POLIAKOVA, E.!., Academy of Science, Institute of Oceanology, 48,34 1980. Lagoonal coast of the Chuckchee Sea in Late 66 (in Russian). Pleistocene and Holocene and the problem of the bar- MEDvEDEv, B.S.; DOLoTov, Y.S., and SHCHERBAKOV,
Journal of Coastal Research, Vol.8, No. :1, 1992 IGU 1989 Portugal Field Symposium 725
FA, 1961. Some pecularities of the South Promorje In: STANLEY, D.J. and SWIFT, D.•J.P. (eds.), Marine coast composition and evolution. Transactions of the Sediment Transport and Environmental Manage USSR Academy of Science, Institute of Oceanology, ment, New York: Wiley, pp. 311-350. 48, 121-144 (in Russian). SWIFT,D.J.P.; DUANE, D.B., and McKINN~~Y,T.F., 1973. NEVESSKY, E.N., 1958. On the Black Sea modern trans Ridge and swale topography of the Middle Atlantic gression. Transactions of the USSR Academy of Sci Bight, North America: secular response to the Ho ence,Institute of Oceanology, 28, 2~1-29 (in Russian). locene hydraulic regime. Marine Geology, 15, 227 NEVESSKY, E.N., 19,59. New data on the origin of the 247. Markitan and Bakal shoals on the Black Sea. Trans SWIFT, D..J.P. and MOSLOW, T.F., 1982. Holocene trans actions of the USSR Academy of Science, Oceano gression in south-central Long Island, New York graphic Commission, 4, 122-126 (in Russian). Discussion. Journal of Sedimentary Petrology, 52, NEVESSKY, E.N., 1960. Evolution of the Kalamit Bay. 1014-1019. Transactions of the USSR Academy of Science. VAN STRAATEN, L.M.J.U.V., 1959. Littoral and suhma Oceanographic Commission, 5, 54-59 (in Russian). rine morphology of the Rhone delta. II Coastal Ge NEVESSKY, E.N., 1961. Some data on the postglacial ography Conference, Washington, D.C.: Coastal evolution of the Karkinit Bay and the depositional Studies Institute, Louisiana State University, pp. 233 processes on its bottom. Transactions of the USSR 264. Academy of Science, Institute of Oceanology, 48, 88 VI.AnIMIROV, A.T., 1958. To the morphology and dy 102 (in Russian). namics of the western Kamchatka shores. Izvestia of PSUTY. N.P .. 1986. Holocene sea level in New -Iersey. the USSR Academy of Science, Geographical Series, Physical Geography, 7, 156-167. 2, 81-87 (in Russian). RAMPINO, M.R. and SANDERS, .J.E., 1980. Holocene VLADIMIHOV, A.T., 1959. The evolution of the western transgression in south-central Long Island, New York. Kamchatka shores during Quaternary period. Trans Journal of Sedimentary Petrology, 50, 106:1-1079. actions of the USSR Academy of Science, Oceano RYER, T.A., 1977. Patterns of Cretaceous shallow-ma graphic Commission, 4, 101-108 (in Russian). rine sedimentation, Coalville and Rockport areas, WALKER, T.R. and THOMPSON, R.W., 19G8. Late Qua Utah. Bulletin Geological Society America, 88, 177 ternary geology of the San Felipe area, Baja Califor 188. nia, Mexico. Journal of Geology, 76, 479-485. SANDERS, J.E. and KUMAR, N., 1975. Evidence of shore ZENKOVICH, V.P., 1946. Dynamics and Morphology of faceretreat and in-place "drowning" during Holocene the Sea-shores. Pt. 1: Wave Processes. Moscow-Len submergence of barriers, shelf off Fire Island, New ingrad: Marine Transport, 496p. (in Russian, English York. Bulletin Geological Society America, 86, 65 summary). 76. ZENKOVICH, V.P., 195:1. On the one type of the disap SCHWARTZ, M.L., 1967. The Bruun theory of sea-level pearing shore accumulative forms. Izvestia of the rise as a cause of shore erosion. Journal of Geology, USSR Geographical Society, 85, 89-93 (in Russian). 75, 76-91. ZENKOVICH, V.P., 1955. The Bakal spit. In: Dynamics SHCHERBAKOV, F.A., 1961. Some data on the postglacial and Morphology of Sea-shores, 4. Moscow: Pub!. transgression of the Bering Sea. Transactions of the House of the USSR Academy of Science (in Russian). USSR Academy of Science, Institute of Oceanology, ZENKOVICH, V.P., 1957. On the origin of the barriers and 48,114-120 (in Russian). lagoonal shores. Bulletin of the USSR Academy of SHCHERBAKOV, F.A., 1983. Continental Margins in the Sci once, Institute of Oceanology, 21, 3-39 (in Rus Late-Pleistocene and Holocene. Moscow: Nauka, 213p. sian). (in Russian). Z~~NK()VICH, V.P., 1962. Principles of the Science of the STUBBLEFIELD, W.L.; KERSEY, D.G., and MCGRAIL, D.W., Sea-shore development. Moscow: Publishing House 1983. Development of middle continental shelf and of the USSR Academy Science, 710p. (in Russian). ridges: New -Iersey. Bulletin American Association ZENKOVICH, V.P. and VLADlMJROV, A.T., 1951. Analysis Petroleum Geologists, 67,817-830. of the shore accumulative terrace composition. Vo SWIFT, D.J.P., 1976. Continental shelf sedimentation. prosy of Geography, 26, 260-266 (in Russian).
o RESUMO 0 A previsao das modificacaes nos amhientes sedimentares costeiros provocadas pela elevacao geral do nivel do mar, pode basear-se nostestemunhos da transgressao Holocenica, apesar da irregularidade desta. As consequencias da elevacao do nivel do mar, na costa, dependem da amplitude da elevacao, e tambern da susceptibilidade a erosao das formas do relevo litoral, I' do novo balance de sedimentos que se estabelece durante I' apos a dinamica de submorsao das formas baixas (de acumulacao) I' devido ao incremento da erosao na base das arribas, nas praias e nas dunas. Nos litorais pouco profundos verificam-se tres tipos de evolucao, dependentes da amplitude da elevacao do nivel do mar I' da disponibilidade de sedimentos: (I) submersao e preservacao das formas de acumulacao; (2) deslocamento das formas de acurnulacao acompanhado pelo recuo das respectivas margens; (:)) progressao continua da linha de costa, a longo termo. Nos litorais profundos verificam-se dois tipos de evoluccao das formas de acurnulacao: (I) interrupcao na acumulacao, tendencia para erosao I' consequente reducao do tamanbo dessas formas; (2) deposicao continua dos sedimentos I' tendencia para urn maior densenvolvimento das formas de acurnulacao. Discutem-se as varias possibilidades de evolucao da costa consoante a inclinacao e a externsao da plataforma litoral, a rapida ou lenta elevacao do nivel do mar I' a disponibilidade de sedimentos na costa setentrional do Mar de Azov.
Journal of Coastal Research, Vol. 8, No. :3, 1992 726 Dolotov
o RESUME 0 La prevision des consequences de l'elevation du niveau de la mer sur la sedimentation littorale peut se faire en analysant les temoins de la transgression holocene, en depit de son irregularite. Ces consequences dependent de l'amplitude et de la vitesse de la rernontee du niveau de la mer, de ia resistance des roches il l'erosion marine et du nouveau bilan sedimentaire littoral, qui s'installe pendant et apres la dynarnique de submersion des formes basses (surtoutcelles d'accumulation), a cause de l'erosion qui est acceleree sur les plages, sur les dunes et sur Ie bas des failases en roches tendres. Sur les littoraux peu profonds on observe trois types d'evolution: (L) submersion et preservation des formes d'accumulation; (2) deplacement et recul des formes d'accumulation; (3) progression, ala longue, de la ligne de rivage, Sur les littoraux profonds deux types d'evolution sont consideres: (I) interruption de l'accumulation et erosion des formes; (2) deposition continue de sediments et engraissement des formes daccumulation. Dans cet article sont aussi exposees les diverses possibilites de changement de la ligne de cote en consequence des rernontees lentes au rapides du niveau de la mer, sur des cotes a large plateforme littorale et sous differentes conditions de bilan sedimentaire. La cote nord de la Mer d'Azov est presentee com me exemple.
I l I I
I, I I I I I r
Journal of Coastal Research, Vol. 8, No.3, 1992 l 1