VNUJournalofScience,EarthSciences23(2007)235‐243 235 Quaternarysedimentarycyclesinrelationto sealevelchangeinVietnam TranNghi*,NguyenThanhLan,DinhXuanThanh, PhamNguyenHaVu,NguyenHoangSon,TranThiThanhNhan CollegeofScience,VNU Received20November2007;receivedinrevisedform15December2007 Abstract.Vietnam has over 3200 km shoreline which extends from north to south of the country. Sealevelchangeswere principalfactorsinfluencedonsedimentaryenvironmentandcompositions. InQuaternary,cyclesofsealevelchangeandtectonicmovementweremainfactorthatcreatedRed River delta, Nam Bo plain and Central  plain. There are 5 sedimentary cycles corresponding to 5 cycles of sea level change of the Red River delta and Nam Bo plain. Sedimentary cycles were characterizedbysedimentarycoefficientssuchas:grainsize,claycontent,indexofcationFe 2+ /Fe 3+ exchange,pHvariationfromthestarttotheendofcycles.Theyarerepresentedbyfluvialterraces, marine terraces, marine notches and peat layers. In central littoral plain, the relationship between sedimentary cycles and sea level is represented by five sandy cycles and distribution of coral terracesinshallowsea. There  are 5 generations of ancient shoreline zones, which correlated with glacial and interglacialperiodsinVietnamesecontinentalshelf:theshorelinein30mwaterdepthiscorrelated with (Q 2 1-2 ). Up to 60 m water depth is correlated with (Q 1 3b ‐Q 2 1 ) and 100‐120 m water depth is correlated with Wurm 2  glaciation (Q 1 3b )(?). In 200‐300 m water depth correlated with Wurm 1  glaciation(Q 1 3a )(?),at400‐500mwaterdepthcorrelatedwithRissglaciation(Q 1 2b )(?),at600‐700m waterdepthcorrelatedwithMindelglaciation(Q 1 2a )(?),andat1000‐1500mwaterdepthcorrelated with Gunz glaciation (Q 1 1 )(?). As such Quaternary sea level changes in mainland and continental shelfinteractedandquitedistinctiveformeachotherbypendulumrule. Keyw ords:Quaternarysedimentarycircles;RedRiverDelt a;CuuLongRiverDelta;Sealevelchange. 1.Introduction *  Vietnamhas over 3200 km shoreline which extendsfromMongCaiinthenorthtoHaTien in the south. Sea level changes had influenced _______ *Correspondingauthor.Tel.:84‐4‐5587059 E‐mail:trannghi@vnu.edu.vn onsedimentaryenvironmentandcompositions and the evolution sedimentary cycle of Red RiverDelta,CuuLongRiverDeltaandCentral Coastalplains.Thesecyclesweredistinguished by absolute age dating include: thermo‐ luminescence age, 14 C dating from wood and shells. Geomorphological characteristics and sedimentary coefficients were used together TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 236 with absoluteages to analyzethecause‐effect relationship between development of sedimentary cycles, sea level changes, and tectonicmovementinQuaternary. 2.Methodology There are many research projects have undertaken by Vietnamese scientists on Quaternary sea level change, especially in Late Pleistocene to Holocene. However, the identification of transgression and regression phases and lithofacies analysis based on quantitative approaches such as material compositions, geochemical environmental coefficients,  have just applied by Tran Nghi, MaiThanhTanandotherworkersin2000,2001 [6, 8]. Therefore, in this paper, we will use the same approaches to analyze the cause‐effect relationshipbetween  lithologicalcharacteristics and lithofacies associations in relation to transgressionandregressionphaseandtectonic movements: fluvial and marine terraces in mainland and in continental shelf that are distributed in different height and depth and compare them to the transgression and regressionsystemofancientshorelines. For investigating mechanism of sedimentary evolutionofRedRiverDelta,Cuu Long River Delta and Central plains, it is necessarytodefinethecause‐effectcorrelation between lithology, sea level change, and tectonic movement. The sedimentary environment has major role in governing petrological compositions in term of lithofacies ‐ paleogeography. The transgression phase is characterized by marshy, lagoonal and deltaic environments. Meanwhile, regression pha ses createdcoarse‐grainedmaterialsofproluvial‐ aluvialenvironments.Therefore,therelationship between sedimentary cycles and sea level change is determined by changing of facies associationaccordingtotimeandspace.Theend of a cycle is marked by a weathering period to form laterite‐bearing,yellowtoredsediments.  Vietnam (Tran Nghi) North West Europe Archaeology Absolute age (Ka) Geological age Sedimentary cycles Regression Transgression Stratigraphy Regression Transgression British Alper (Penk) Italy Middle East Poland (Sapherlevin) Russia (Lakovlep) North of America (East) Human species Cultural periods Q 2 3 ? HOLO- CENE Holocene Flandrian Transgression Holocene Transgression Holocene Transgression Holocene Transgression “Nizza” Transgression Holocene Transgression Transgression Mogine Holocene Transgression Mesolithic and Neolithic Q 1 3b -Q 2 3 Regression Regression W 2 Regression Baltic Glaciation Astakop- vandai Viskosine (2) Modern human Upper Q 1 3b ? Weich- sebian Transgression Regression Khanstanton W 1 -W 2 ? W 1 Regression Muzur Vacsava II Deglaciation Mologo sek nhim Kalinin V 1 -V 2 Viskosine (1) Nean- dectane Middle Late Eemian Transgression Upper Ixla Khocnen R-W 1 Pantinian Tyrhenian Mazoves II Mikulin Odinsop Q 1 2b-3a ? Saalian Regression Dzippin Riss Regression Vacsava I Dnheprop Holsterian Transgression Lower Khocnen M-R ? Mazoves I Likhvin Pre Nean- dectan and pre Sapien Lower Middle Q 1 2a ? Elsterian Regression Logestophoc Glaciation Mindel Regression Krakop Acient glaciation 1,2 Cromeriam complex Transgression Cromerian G-M Cromerian Roman crotorian Sandomir Acient deglaciation Q 1 1b ? Menapian Regression Crue Gun Cassia Siciian Laroslap Acient glaciation Early Paleolithic Waal D-G PLEISTOCENE Early Q 1 1a ? Eburonian D Emilian Tiglian Practiglian 10 125 700 900 1.6 2-2.5 Ma PLIOCENE Reuverian Heidel- berg species Fig.1.Comparisonofsealevelchange‐glacial‐interglacial‐sedimentarycyclesandgeologicalage[9]. TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 237 Themainmethodsusedinthispaperare: ‐Petrologicalanalysismethodwascarriedout using thin sections, made by cementing epoxy ofunconsolidatedsands. ‐Granulometricanalysisofsandwasusedby sets of sieve or pipet of different fractions and then granulometric parameters (Sorting‐So, Asymetric coefficient‐Sk, average grain size‐ Md)wereobtainedbyaPCsoftware. ‐ Geochemistry environmental coefficientsof sediments was measured by specialized meter andthenobtained:pH,Eh,Kt,Fe 2+ /Fe 3+ These pH‐alkaline‐acidindex,Eh‐redoxpotention index,Kt=(Na + +K + )/(K 2+ +Mg 2+ )exchanging cation coefficients were  applied in lithofacies association analysis and reconstruction of paleogeographicallandscape. 3. Transgression‐regression cycles of Red River Delta, Cuu Long River Delta, Central plaininQuaternary RedRiverDelta(RRD)andCuuLongRiver Delta(CLRD)arethebiggestplainsinVietnam. Developing history and sedimentary evolution of both deltas have closely related with sea level changes in Quaternary in which regression were according Gunz, Mindel, Riss, Wurm 1 ,Wurm 2 glacialphasesandtransgressions were correlated with interglacial phases and  Flandrientransgression. Five sedimentary cycles in RRD and CLRD werecorrelatedwith5stratigraphicformations: inearlyPleistocene(Q 1 1 ),Middle‐LatePleistocene (Q 1 2-3a ),LatePleistocene(Q 1 3b ),latepartofLate Pleistocene‐Middle Holocene (Q 1 3c ‐Q 2 2 ) and Late Holocene in each delta (Fig. 1‐6) [2]. The beginning of a cycle wa s related with coarse grained size pebbles, sands proluvial and alluvialfaciessedimentwhatismainlandorigin and the ending was related with fine grained sizesilt,claydeltaicandlagoonalfacies. 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 Depth (m) BH59-64 605 BH-11 105 To Lich river Red River BH2-HN 156 BH3-HN 180 BH4-HN a.amQ 2 3 tb a.amQ 2 3 tb apQ 1 2 -3 hn a.amQ 2 3 tb am lbQ hh 2 1-2 amQ 1 3b vp amQ 1 3b vp amQ 1 3b vp aQ 1 1 lc N 2 2 vb aQ 2 3a tb ~ . ~ . ~ . ~ ~ . ~ . ~ ~ . ~ . ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . ~ . aQ 2 3 tb a.amQ 2 3 tb  Fig.2.Litho‐faciescrosssection inthecenterofRedRiverDelta[3]. ha no i Thai Nguyen Viet Tri Phuc Yen Son Ta y Ha Dong Hung Yen Hai Duong Hai Phong Kien Xuong Vinh Ni nh Nam Dinh aQ 2 3a tb aQ 2 3b tb N 2 > 8 0 m Q : 6 0 - 8 0 m 1 1 l c Q 1 2 - 3 a h n Q 1 3 b v p N a m Q 2 3 t b m m b Q 2 1 - 2 h h a m Q 2 1 - 2 h h a Q 1 3 b v p a p Q 1 2 - 3 h n a p Q I I - I I I 1 h n a p Q 1 1 l c a p Q I l c Red River Dam Te rr ac e Aluvial - proluvial pebbles - gravel facies Plain channel deposited facies Spotted weathering marine clay Eroided area ap a m h 2 h 1 Q 2 1-2 hh  Fig.3.Blockdiagramofalluvialfacies inRedRiverDelta[11]. Thefirstsedimentarycycle(EarlyPleistocene, Le Chi Formation in RRD and Trang Bom Formation in CLRD) are characterized by coarse grained size sediment with content of pebbles‐gravel increased from 15 to 20.8% in RRD and 13.8% in CLRD [2]. The ending of cycles was correlated with interglacial phase, silty claydeltaic‐marshyfacies(Md=0.1‐0.5mm in RRD and Md=0.018‐0.439 mm in CLRD). TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 238 During maximum sea level rise, erosion‐ accumulationterraces of55‐70mhigh inNEof RRD were  formed. Meanwhile, lit hofacies associationofsandybarriersandlagoonalfacies isthemainfeatureinCentralcoastalplainfrom Quang Binh Province to Mui Ne‐Phan Thiet, BinhThuanProvince. The second sedimentary cycle from Middle ‐ Late Pleistocene (Hanoi Formation in RRD andThuDucFormationinCLRD)iscomprised by thick pebble‐gravel layer (10‐80 m) of mountainous river and proluvial facies (Md=0.2‐1 mm in RRD and Md=2.3 mm in CLRD[2]).Bytheendofthissedimentarycycle, rock composition composes of clayish marshy and clayish silt deltaic facies in Thanh Hoa plain, RRD, CLRD, and ancient sandy bars, tombololagoonalfaciesinCentralplain. Thethird sedimentarycyclecorrespondsto Late Pleistocene (Vinh Phuc Formationin RRD and Cu Chi or Moc Hoa in CLRD), which contains coarse  and medium grained sands of riverbedfaciesandpassingupwardsintosand levee facies, silty clay flood plain and clay marshy, greenish lagoonal facies. In Central plain, late Pleistocene transgression phase createdbigvolumeofwhitequartzsandybars. However,thesewhitesandhavebecameyellow sanddueto infiltrationweathering. 30 30 20 20 10 10 0 0 -10 -10 -20 -20 -30 -30 -40 -40 -50 -50 -60 -60 -70 -70 -80 -80 -90 -90 Tam G ia n g la g oon BH 407 BH 314 BH 312 Huong river Q 1 3b mQ 1 3b amQ 2 3 mQ 2 1-2 mvQ 1 2-3a mvQ 1 3b aQ 1 2-3a amQ 1 2-3a amQ 1 1 aQ 1 1 mvQ 1 1 mQ 1 1 mQ 1 3b mQ 2 1-2 mvQ 2 3 mQ 2 3 mQ 1 2-3a  Fig.4.Litho‐faciescrosssection ofThuaThienHuePlain[4]. The fourth sedimentary cycle was formed duringperiodfromLatestPleistocenetoEarly‐ MiddleHolocene(HaiHungFormationinRRD and Tan Thanh or Binh Chanh Formation in CLRD). This sequence is characterized by Flandrien transgression sedimentary facies complex and composed of sandy silt of deltaic facies,claysiltrichin organicmaterialandpeat ofmarshy facies. These layers were coveredby grey‐greenishclayoflagoonalfacies.Thecoastal plains in Central Vietnam, from Nghe An to BinhThuanprovinces,composeofacombinat io n of coastal sandy bars and lagoons occuring inside sandy bars. The associations of tombolo and bay was quite typical in South Central Vietnam, especially in Khanh Hoa Province. a a a a a a m Q 2 2 - 3 a b Q 2 2 - 3 a b Q 2 2 - 3 a m Q 2 1 - 2 a m Q 2 1 - 2 a m b Q 2 1 - 2 m b Q 2 1 - 2 a m Q 2 1 - 2 0 20 -10 0 -20 0 0 20 -100 Lk17 Lk209 Lk214a Lk31MT Lk325 500 400 479.6 501.7 396.2 Lk812 339.6 Lk819 203.9 Vam C o Dong River Sai Gon River Lk816 169 Co Chien River Ham Luong River Vam C o Tay River Dong Nai River + + + + +++ + + U U U U U U UU U U U U Lk817 75 Lk818 396 Bk11 80 Hau River Tien River Fig.5.SedimentarycrosssectioninCuuLongRiverDelta[9]. TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 239 Geological Age Age of Sedimentary Cycles TL age (Ka) No samples and place name Sandy cycles Lithology Lithology Envi. Envi. Cycles of lagoonal plain Detrital minerals of sandy barrier Q (%) F(%) R(%) Sorting Rounding Sea level (Reg - Trans) So Ro H O L O C E N E Early - Middle Late P L E I S T O C E N E Early Middle Late Late Holocene Late Pleistocene Middle Holocene Late Pleistocene Middle - Late Pleistocene Late part of. Early Pleis 10 6 125 700 1.6 Ma Q 2 3 Q-Q 12 3c 1-2 Q 1 3b Q 1 2-3a Q 1 1 14+2 14+2 28+4 48+6 52+7 62+6 85+9 99+19 101+17 103+11 122 >181 >204 108+49 VN44 VN12 VN45 VN37 VN18 VN30 VN15 VN12b VN31 VN20 VN29 VN32 VN14b VN14 Bau Trang Tuy Phong P. T Airport Suoi Tien Chi Cong S. Song Luy Suoi Tien Tuy Phong Hon Rom Chi Cong S. Song Luy H. Rom Suoi Tien Suoi Tien mv m mv m. mv? m mv m mv am, m am m mb a, am m am a m am a m am a 98-100 95-9892-98 92-98 90-98 0-1.00.5-2.01-3.01.0-2.01.0-3.0 0-1.0 0.5-3.0 1.0-8.0 1.0-7.01.0-7.0 1.2-1.51.3-1.71.3-1.81.5-1.81.5-1.8 0.6-1.0 0.6-0.9 0.5-0.9 0.6-0.9 0.6-0.8 W2 W1-W2 W1 R-W1 R M-R M G-M G  Fig.6.Comparisonofthermoluminescenceagesofquartzsandybarrier andsedimentarycyclesinBinhThuanProvince,Vietnam[9]. The fifth sedimentary cycle was formed in Late Holocene regression phase (Thai Binh Formation in RRD and Can Gio Formation in CCRD).Thiscycleisdominatedby sands,silts, clay alluvial facies in upper part and silt, clay deltaic plain, grey clay marshy and sand silt clay deltaic front facies in  lower part. Besides, Late Holocene eolian sediments have been formedbywindreworkingoldsandyformation. In addition, the fifth cycle was also eolian sedimentinsandybarsandsandydunesin CLRD. 4.Thermoluminescenceageofredsandycycles inPhanThiet‐BinhThuanprovinces The coastline of South Central Vietnam is dominated by extensive sandy coastal barrier successions of Early Pleistocene, Middle‐Late Pleistocene, LatePleistoceneandLatePleistocene toEarly‐MiddleHoloceneandLateHolocene. The first cycle: an angular tektite layer coveredalternativeredandwhite‐yellowsand barrier of Early Pleistocene. Probably, this red sandsuccession shouldhaveageolderthanthe age of tektites (i.e. before 700 Ka) [1]. The comparison of these successions with glacial and interglacial in the world (Fig. 1) correspondstointerglacialGunz‐Mindel.  Fig.7.Thesequenceofredsandandlightgreysand, ChiCong,BinhThuanProvince,Vietnam[7]. The second cycle, composing of 2 rhythms, was possibly equivalent to older grey‐white, wellcementedsandbarrierofMiddlePleistocene age (Q 1 2a ) (TL age of >204 Ka [1]). Moderate cemented red sand barrier of Middle‐Late Pleistocenearedominatedbyinnerbarriers.The TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 240 sandy samples yielded an age of 103±11 Ka , 101±17Ka[1],possiblyequivalenttostage5oflast interglacialsensulatooftheOxygenIsotoperecord . Thethirdcyclecomprisesbyaseriesofred and yellow sand successions of barriers dominated in coastal zone of South Central Vietnam from Phan Thiet to Tuy Phong. This cycle over lies of Middle‐Late Pleistocene sandy barrier successions the boundary between second cycle is exposed and third cycle in Hon Rom, Chi Cong, Suoi Tien and Song Luy. The alternation of red sand and yellowsandrhythmsrelatedtosealevelchange  andinfiltrationweatheringinlatePleistocene. SampleVN31yieldedanage101±17Ka[1]. Sample VN31 yieldedan age of 101±17 Ka, andVN32‐anageof108±49Ka(HonRom)[1]. ThisagerangebelongstoLatePleistocenecycle whicharesuggestiveofdepositionduringstage 5(sensulato)oftheOxygenIsotoperecord. Thefourthcyclecomposedoftworhythms: an eolian red sand dunes of Late Pleistocene (sampleat Phan Thiet airport yieldeda TL age of 28±4 Ka) correlated with stage 2 and 3, and white sand barriers oxygen isotope to be equivalent with  last glacial maximum (W 2 ) of Early‐MiddleHolocene. The fifth sandy cycle reworked Holocene quartzsandybarriertoformsand duneduring 3Katopresent.TheSouthCentralcoastalzone betweenPhanThietandTuyPhongisdominated on surface by light yellow active dune fields due to reacting of wind,  possibly correlated  withHoloceneregressionandsealevelrise. 5. Cycles of coral reef in relation to sea level change in coastal zone and shallow sea of CentralVietnamarea Coral reefs occur in 3 locations in shallow seaofSouthCentralVietnam(Fig.8). Middle‐LatePleistocenecoralreefs,which were calcified,occur in Hon Do‐Ninh Thuan. This layer is covered by red sand. Late Pleistocene coral reef terrace is distributed in 20‐25 m water depth. Middle Holocene coral reef terraces are located in 1‐2 m water deep yieldandageof5000yearBPbyC 14 dating. Distribution of calcified coral reefs in comparisonwithredsand(19Ka)showedthat: this layer could have been formed in Middle‐ Late Pleistocene transgression and Vinh Phuc transgression that created red sand and coral reefin20‐25mwaterdepth.Theredsandlayer coversthecoral.              Fig.8.DevelopmentperiodsofcoralinSouthCentral area(HonGomPeninsula). Thecoralterracein20‐25mwaterdepthwas formedinFlandriantransgression.Thiswasthe second sea level stands in Holocene and it is correlative to ancient shorelines. The coral reef at 1‐2m water depth, formed in Early‐Middle Holocene,iscorrelatedwithwhitesandinCam  RanhandHonGom. Q 2 1-2 Q 1 3b 20-25m Q 2 2 Q 2 3 Q 2 2 Q 1 3b m v Q 2 3 Red-Yellow sand White sand 5 K a a c b TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 241  Fig.9.LateritegravelinbottomsedimentinSW EasternSea.  Fig.10.Foraminifera,diatomea,quaczitefragments andfragmentsofdaciterockinbottomsedimentsin SWofEasternSea.  Fig.11.WeatheringspottedclayinLatePleistocene sedimentinSWofEasternSea. 6.Quaternaryshorelinesinbottomofcontin ental shelfofVietnam 6.1.Ancientshorelines The well‐sorted and well‐round ancient sandy bars distributed parallel to modern shoreline. Well‐round laterite gravels are situated in sea bottoms far from modern coastline. This layer is covered by spotted clay la yer which containedlaterite curdles. Concentrationofcoarse‐grainedterrigeneous sediment and moderate to well‐roundness bioclasts[9]. Location of ancient shoreline in continental shelf[8]: ‐In30mwaterdepthcorrelatedwith(Q 2 1-2 ). ‐In60mwaterdepthcorrelatedwith(Q 1 3b ‐Q 2 1 ). ‐ In 100‐120 m water depth correlated with Wurm 2 glaciation(Q 1 3b ). ‐ In 200‐300 m water depth correlated with Wurm 1 glaciation(Q 1 3a ). ‐ In 400‐500 m water depth correlated with Rissglaciation(Q 1 2b ). ‐ In 600‐700 m water depth correlated with Mindelglaciation(Q 1 2a ). ‐In1000‐1500mwaterdepthcorrelatedwith Gunzglaciation(Q 1 1 ). 6.2. Relationship between marine terraces and sedimentarycyclesintheseabottom In Quaternary, appearance of fluvial and marine terraces in mainland and continental shelf are the results of uplift‐subsidence movements and transgression‐regression phases. Five ancient marine terraces on mainland and 6 on continental shelf [9] from Pleistocene toHoloceneagescanbeidentified. These terraces have symmetric relation, it means that the oldest marine terrace on mainlandisathighestelevation(highestpoint) and the oldest marine terrace on continental shelfisatlowestelevation(deepestpoint)(Fig. 12). The marine terraces on mainland and continental shelf of the same age were formed in the same sedimentary cycle. These periods extended from Pleistocene to Holocene. Thus, sea level changes combined with uplift activities on mainland and subsidence in sea bottom characteristic marine terraces systems hadproduced. TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 242 Height (m) Terraces Sea terraces on mainland Age of Continental shelf sediment 100 80 60 40 20 10 0 -50 -100 -200 -400 -500 -600 -2000 -2500 Qb I VI V V IV III II I I II III IV V VI Qa I Qa I Qa II Qa II Q-Q a II III 1 Qa III 1 Q III 2 Q III 2 Q-Q III IV 21 Q IV 3 Q IV 3 Q IV 3 Q IV 2 Qb II-III 1 Qb III 2 Q I Q III Q IIIB 2 Q IIIA 2 Q IIIb 2 Q II 1 Q I 1 Q IV 2 Q IV 3 Q IV 3 Q-Q III IV 21 Q-Q III IV 21 Q IIIa 1 1 120 7 7 6 6 5 5 4 4 3 3 22 2 1 1 Glacier phases Wurm (W) Riss (R) Mindel (M) Gunz (G) Dunai (D)  Fig.12.RelationshipbetweenseaterracesandPliocene‐Quaternarysedimentarycycles incontinentalshelfofVietnam[10]. 7.Conclusions In Quaternary, cycles of sea level change and tectonic movement cycles are the main reasons, which  create Red River Delta, Cuu LongRiverDeltaandCentralplain.Thereare5 sedimentarycyclescorrespondingto5cyclesof sea level change in Red River Delta, Cuu Long River Delta, and  Central plain. In Central littoral plain, the relationship between sedimentary cycles and sea level change is characterized by 5 sandy cycles and distributionofcoralterracesinshallowsea. Thereare5generationsofancientshoreline zones,whichcanbecorrelatedwithglacialand interglacial phases in Vietnamese continental shelf: at30mwaterdepthcorrelatedwithQ 2 1-2 ; at60mwaterdepthcorrelatedwithQ 1 3b ‐Q 2 1 ;at 100‐120 m water depth correlated with Wurm 2  glaciation Q 1 3b ; at 200‐300 m water depth correlatedwithWurm 1 glaciation(Q 1 3a );at400‐ 500 m water depth correlated with Riss glaciation Q 1 2b ; at 600‐700 m water depth correlated with Mindel glaciation Q 1 2a ; and at 1000‐1500 mwaterdepthcorrelatedwithGunz glaciationQ 1 1 .Theseanc ientshorel inescorrelated with marine terraces and 6 sedimentary cycles incontinentalshelf. References [1] V.M.W. Colin, G.J. Brian, Tran Nghi, M.P. David, et al., Thermoluminescence ages for a reworkedcoastalbarrier,southeasternVietnam: a preliminary report, Journal of Asian Earth Sciences20(2002)535. [2] Nguyen Huy Dung et al., Neogene‐Quaternary stratigraphicaldivision andNamBo plainstructure research, Department of Geology and Mineral Resource,Hanoi,2003(inVietnamese). [3] TranNghi,NgoQuangToan, Characteristics of sedimentary circles and history of Quaternary geology of Red River Delta, Journal of Geology 206‐207(1991)31(inVietnamese). [4] Tran Nghi, Circles of marine transgression, regression, and formation history of Central plains in Quaternary,  New discoveries in archeology in 1995 year, Hanoi, 1996 (in Vietnamese). [5] Tran Nghi, Evolution of coastal sandy formations in Central Vietnam in relationship TranNghietal./VNUJournalofScience,EarthSciences23(2007)235‐243 243 with the oscillation of sea level in Quaternary. Project Marine geological research and Geophysics (II),InstituteofOceanography,Hanoi,1996. [6] Tran Nghi, Nguyen Dich Dy, Dinh Van Thuan, VuVanVinh,MaKongCo,TrinhNguyenTinh, Phan Thiet red sands‐material composition, provenance, mechanism of formation and evolutionin relationwithsealevelchangesand neotectonics, Proceedings of The first scientific conference, Hanoi UniversityofScience,1998(in Vietnamese). [7] Tran Nghi et al., Environment and mechanism of red sand formation in Phan Thiet Province, JournalofGeology245A(1998)31(inVietnamese). [8] TranNghi,MaiThanhTan, DoanDinhLam,La The Phuc, Dinh Xuan Thanh, Nguyen Dinh Nguyen,Characterist icsofPliocene‐Quaternary lithofacies‐paleogeographyinshelfof Vietnam, Journal of Sciences of the Earth, 23 (2001) 35 (in Vietnamese). [9] Tran Nghi, Mai Thanh Tan, Dinh Xuan Thanh, Nguyen Thanh Lan, The sea level change problem in Quaternary based on sedimentary research in littoral and shallow sea from Nha Trang to Bac Lieu, Proceedings of Scientific conference Geotechnics and Marine Geology, Da Lat,2003(inVietnamese). [10] Tran Nghi, Textbook on  sedimentology, VNU PublishingHouse,Hanoi,2003(inVietnamese). [11] Tran Nghi, Textbook on marine geology, VNU PublishingHouse,Hanoi,2005(inVietnamese). . VNUJournalofScience,EarthSciences23(2007)235‐243 235 Quaternary sedimentary cycles in relation to sea level change in Vietnam TranNghi*,NguyenThanhLan,DinhXuanThanh, PhamNguyenHaVu,NguyenHoangSon,TranThiThanhNhan CollegeofScience,VNU Received20November2007;received in revisedform15December2007 . country. Sea level changeswere principalfactorsinfluencedon sedimentary environmentandcompositions. In Quaternary, cycles of sea level change andtectonicmovementweremainfactorthatcreatedRed River