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Titolo:
Paleocurrent analysis for the Late Pleistocene-Holocene incised-valley fill of the Yangtze delta, China by using anisotropy of magnetic susceptibility data
Autore:
Liu, B; Saito, Y; Yamazaki, T; Abdeldayem, A; Oda, H; Hori, K; Zhao, Q;
Indirizzi:
AIST, MRE Geol Survey Japan, Tsukuba, Ibaraki 3058567, Japan AIST TsukubaIbaraki Japan 3058567 Japan, Tsukuba, Ibaraki 3058567, Japan Tanta Univ, Fac Sci, Dept Geol, Tanta 31527, Egypt Tanta Univ Tanta Egypt 31527 niv, Fac Sci, Dept Geol, Tanta 31527, Egypt Univ Tokyo, Grad Sch Sci, Dept Geog, Bunkyo Ku, Tokyo 1130033, Japan Univ Tokyo Tokyo Japan 1130033 ept Geog, Bunkyo Ku, Tokyo 1130033, Japan Tongji Univ, Marine Geol Lab, Shanghai 200092, Peoples R China Tongji Univ Shanghai Peoples R China 200092 ghai 200092, Peoples R China
Titolo Testata:
MARINE GEOLOGY
fascicolo: 1-4, volume: 176, anno: 2001,
pagine: 175 - 189
SICI:
0025-3227(20010615)176:1-4<175:PAFTLP>2.0.ZU;2-Q
Fonte:
ISI
Lingua:
ENG
Soggetto:
CYCLOSTRATIGRAPHY MSEC; LATE QUATERNARY; STRATIGRAPHY; LOESS; SEDIMENT; EVENT; ROCKS;
Keywords:
anisotropy of magnetic susceptibility (AMS) Yangtze delta; paleocurrent; tide-dominated; incised-valley fill;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Physical, Chemical & Earth Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Liu, B AIST, MRE Geol Survey Japan, Higashi 1-1-1, Tsukuba, Ibaraki 3058567, Japan AIST Higashi 1-1-1 Tsukuba Ibaraki Japan 3058567 aki 3058567, Japan
Citazione:
B. Liu et al., "Paleocurrent analysis for the Late Pleistocene-Holocene incised-valley fill of the Yangtze delta, China by using anisotropy of magnetic susceptibility data", MARINE GEOL, 176(1-4), 2001, pp. 175-189

Abstract

Anisotropy of magnetic susceptibility (AMS) analysis has been conducted onsamples from borehole core CM-97 from the Yangtze River (Changjiang) incised-valley fill, China, to determine the paleocurrent directions to help in reconstructing sedimentary paleoenvironments. Borehole CM-97 consists of fluvial (Unit 1), estuarine (Units 2-6), and deltaic (Units 7-9) sediments after the Last Glacial Maximum in ascending order. The AMS results show that the paleocurrent directions for the tide-dominated estuarine and deltaic sediments were westerly or northwesterly directed (flood-tide dominated), butgive no definite trend for the fluvial sediments. Comparison between the paleocurrent directions inferred from primary sedimentary structures and in situ AMS data shows that they are in good agreement, confirming the applicability of AMS as a good paleocurrent indicator forsediments deposited in coastal tide-dominated environments. Considering that these sediments were strongly tide-influenced and the tidal pattern since 12 kyr BP has not changed significantly, we think that the westerly or northwesterly current direction most probably resulted from flood-tidal currents, and the sedimentary paleoenvironment was a hood-tide dominated estuaryor delta. Additionally, it has been found that downhole changes of some AMS parameters, including the mean magnetic susceptibility (K), the corrected anisotropy degree (P-j) and the magnetic foliation (F), clearly mark the defined stratigraphic boundaries in the borehole. This further extends the validity ofAMS as a good stratigraphic marker in addition to its long known credibility as a sensible paleocurrent recorder. (C) 2001 Elsevier Science B.V. All rights reserved.

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Documento generato il 28/09/20 alle ore 01:23:36