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Article: Late Quaternary environmental changes in the Pearl River mouth region, China

TitleLate Quaternary environmental changes in the Pearl River mouth region, China
Authors
Issue Date2009
PublisherElsevier Ltd. The Journal's web site is located at http://www.elsevier.com/locate/quaint
Citation
Quaternary International, 2009, v. 206 n. 1-2, p. 35-45 How to Cite?
AbstractThis study presents findings concerning Late Quaternary environmental changes in the Pearl River mouth region, China based on the study of over 300 boreholes. Out of these, 35 boreholes are selected for the reconstruction of transects across the deltaic plain and estuary. 39 radiocarbon dates obtained from these boreholes are used to help define the chronology of stratigraphic units present including two terrestrial units (T1 and T2) and two marine units (M1 and M2). Diatom assemblages are studied in 6 boreholes revealing similarities and differences between the two marine units. Before the area was inundated by the last interglacial sea (MIS 5), an older terrestrial unit of sand and gravel (T2) was laid down in a number of palaeo-valleys. During the last interglacial period, an older marine unit of silt and clay (M2) was laid down which was subsequently subaerially exposed when sea-level regressed during the last glacial period (MIS 4-2) causing the uppermost section to be weathered. During the same period, a younger terrestrial unit of sand and gravel (T1) was deposited along palaeo-river channels. Around the early Holocene before 8.2 cal. ka BP, the postglacial rise in sea level initiated a new phase of sedimentation in the outer part of the estuary, characterised by the high percentages of marine diatoms in the sediments. In the early Holocene, strong monsoon freshwater discharge resulted in sedimentation of a fine-sand layer in the inner part of the estuary. After 8.2 cal. ka BP, rapid rises in sea level caused widespread marine inundation and sedimentation. The diatom data suggest that the relative sea level associated with the M2 and M1 units were both at similar levels. Because the M2 unit is typically recorded at altitudes of 15 m and 20 m below the present sea level, this is likely to be a result of long-term subsidence. Although numerical dating of the pre-M1 units has not been made in the present study, the chronology of these units can be inferred from uranium-series ages and optically stimulated luminescence dating obtained from the adjacent coastal waters of Hong Kong. The T1 unit has yielded ages of about 30.0 cal. ka BP while the M2 unit has yielded ages about 130.0 cal. ka BP confirming their MIS 4-2 and MIS 5 ages respectively. © 2008 Elsevier Ltd and INQUA.
Persistent Identifierhttp://hdl.handle.net/10722/58687
ISSN
2015 Impact Factor: 2.067
2015 SCImago Journal Rankings: 1.123
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorZong, Yen_HK
dc.contributor.authorYim, WWSen_HK
dc.contributor.authorYu, Fen_HK
dc.contributor.authorHuang, Gen_HK
dc.date.accessioned2010-05-31T03:35:02Z-
dc.date.available2010-05-31T03:35:02Z-
dc.date.issued2009en_HK
dc.identifier.citationQuaternary International, 2009, v. 206 n. 1-2, p. 35-45en_HK
dc.identifier.issn1040-6182en_HK
dc.identifier.urihttp://hdl.handle.net/10722/58687-
dc.description.abstractThis study presents findings concerning Late Quaternary environmental changes in the Pearl River mouth region, China based on the study of over 300 boreholes. Out of these, 35 boreholes are selected for the reconstruction of transects across the deltaic plain and estuary. 39 radiocarbon dates obtained from these boreholes are used to help define the chronology of stratigraphic units present including two terrestrial units (T1 and T2) and two marine units (M1 and M2). Diatom assemblages are studied in 6 boreholes revealing similarities and differences between the two marine units. Before the area was inundated by the last interglacial sea (MIS 5), an older terrestrial unit of sand and gravel (T2) was laid down in a number of palaeo-valleys. During the last interglacial period, an older marine unit of silt and clay (M2) was laid down which was subsequently subaerially exposed when sea-level regressed during the last glacial period (MIS 4-2) causing the uppermost section to be weathered. During the same period, a younger terrestrial unit of sand and gravel (T1) was deposited along palaeo-river channels. Around the early Holocene before 8.2 cal. ka BP, the postglacial rise in sea level initiated a new phase of sedimentation in the outer part of the estuary, characterised by the high percentages of marine diatoms in the sediments. In the early Holocene, strong monsoon freshwater discharge resulted in sedimentation of a fine-sand layer in the inner part of the estuary. After 8.2 cal. ka BP, rapid rises in sea level caused widespread marine inundation and sedimentation. The diatom data suggest that the relative sea level associated with the M2 and M1 units were both at similar levels. Because the M2 unit is typically recorded at altitudes of 15 m and 20 m below the present sea level, this is likely to be a result of long-term subsidence. Although numerical dating of the pre-M1 units has not been made in the present study, the chronology of these units can be inferred from uranium-series ages and optically stimulated luminescence dating obtained from the adjacent coastal waters of Hong Kong. The T1 unit has yielded ages of about 30.0 cal. ka BP while the M2 unit has yielded ages about 130.0 cal. ka BP confirming their MIS 4-2 and MIS 5 ages respectively. © 2008 Elsevier Ltd and INQUA.en_HK
dc.languageengen_HK
dc.publisherElsevier Ltd. The Journal's web site is located at http://www.elsevier.com/locate/quainten_HK
dc.relation.ispartofQuaternary Internationalen_HK
dc.titleLate Quaternary environmental changes in the Pearl River mouth region, Chinaen_HK
dc.typeArticleen_HK
dc.identifier.openurlhttp://library.hku.hk:4550/resserv?sid=HKU:IR&issn=1040-6182&volume=206&spage=35&epage=45&date=2009&atitle=Late+Quaternary+environmental+changes+in+the+Pearl+River+mouth+region,+Chinaen_HK
dc.identifier.emailZong, Y: yqzong@hku.hken_HK
dc.identifier.emailYim, WWS: wwsyim@hku.hken_HK
dc.identifier.authorityZong, Y=rp00846en_HK
dc.identifier.authorityYim, WWS=rp01746en_HK
dc.description.naturelink_to_subscribed_fulltext-
dc.identifier.doi10.1016/j.quaint.2008.10.012en_HK
dc.identifier.scopuseid_2-s2.0-69249216518en_HK
dc.identifier.hkuros157228en_HK
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-69249216518&selection=ref&src=s&origin=recordpageen_HK
dc.identifier.volume206en_HK
dc.identifier.issue1-2en_HK
dc.identifier.spage35en_HK
dc.identifier.epage45en_HK
dc.identifier.isiWOS:000270286500005-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridZong, Y=7005203454en_HK
dc.identifier.scopusauthoridYim, WWS=7007024728en_HK
dc.identifier.scopusauthoridYu, F=35747418400en_HK
dc.identifier.scopusauthoridHuang, G=7403425099en_HK

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