Provenance Study of Holocene Sediments in Subei Coastal Plain ——Comparison between elemental geochemistry and heavy mineral methods
-
摘要: 运用元素地球化学与重矿物方法对苏北滨海平原全新世沉积物物源进行的比较研究表明，沉积物形成主要由长江与黄河提供物质来源，且又以黄河物源为主。全新世早期长江物质对本区影响范围大于黄河，黄河供给泥沙量较少，对本区影响主要在北部、中部地区。全新世最大海侵之后，黄河曾由苏北入海并携带了大量泥沙，其影响范围明显大于长江，长江仅由狭窄的汊道提供有限的物质而影响范围较小。最近2000年来本区沉积物物源主要由黄河提供。分析表明元素地球化学方法在沉积物物源判别时，可有效的避免水动力因素影响，而相对重矿物方法取得较好的效果。Abstract: Element geochemical and heavy mineral methods are applied to study provenance of Holocene sediments in Subei coastal plain. Based on core analyses, that sedimentary strata developed in Subei coastal plain during Holocene mainly include littoral facies, offshore-neritic facies and tidal flat facies from the lower part to the upper part. The authors firstly resarched elemental and heavy mineral compositions of the Changjaing and the Huanghe sediemnts, and study shows there are obvious differences between both sediments. Some elements and heavy minerals can be applied to trace the Changjiang and the Huanghe sediments and study the diffusions and mixture of both rivers in coastal zones. And then, elemental and detrital mineral compositions of Holocene sediments from four drilling cores in Subei coastal plain are determined in detail. Analyses reveal that the Huanghe River is the dominant provenance and supplied more matters for formation of Holocene sediments than the Changjiang River. During early Holocene, influence of the Changjiang matter exceeded that of the Huanghe matter. After the maximal transgression in Holocene, the Huanghe River arrived the South Yellow Sea and carried abundant sediment, and the Changjiang River supplied limited matter by a narrow distributary and its influence was small. During the last two thousand years, sediments of this area were mainly from the Huanghe River. Study also shows that elemental geochemical method is more useful than heavy mineral method in provenance discrimination because the former can effectively avoid the influence of hydraulic sorting.
-
Key words:
- provenance /
- Subei coastal plain /
- Holocene /
- elemental geochemistry /
- heavy mineral
-
[1] 1 李从先，张家强，杨守业等.苏北陆上潮成沙体的特征与古环境演化[J].中国科学，1998,28(5):418～424
2 陈希祥.苏北黄淮平原全新统沉积特征[J].地层学杂志，1989，3：213～218
3 赵全基.河流对江苏海岸发育影响[J].海洋科学，1992，3：53～55
4 张毅.江苏省海岸沉积物来源及其矿物特征[J].海洋科学，1990，4：34～41
5 张忍顺.苏北黄河三角洲及滨海平原的成陆过程[J].地理学报，1984，2；173～184
6 Morton A C. Heavy minerals in provenance studies. In: Zuffa G G， ed. Provenance of Arenites[C]. Reider, Dordrecht, 1985, 249～277
7 Garver J I,Royce P R, Smick T A. Chromium and Nickel in shale of the Taconic Foreland: A case study for the provenance of fine-grained sediments with an ultramafic source[J]. J. Sedi. Res., 1996, 66(1):100～106
8 Wronkiewcz D J， Condie K C. Geochemistry of Archean shales from the Witwaterstrand Supergroup,South Africa: Source-area weathering and provenance[J]. Geochim.Cosmochim.Acta., 1987, 51:2401～2416
9 Rollinson H R. Using Geochemical Data: Evaluation,Presentation,Interpretation[M]. Longman Scientific and Technical, 1993.
10 Grigsby J D. Chemical fingerprinting in detrital ilmenite: a viable alternative in provenance research ?[J]. J. Sedi.Petrol., 1992, 62(2):331～337
11 Cullers R L,Barret T, Carlson R, et al. REE and mineralogic changes in Holocene soil and stream sediment[J]. Chem. Geol., 1987, 63:275～297
12 耿秀山.中国东部陆架古河系[J].海洋科学，1981，2：21～26
13 任美鄂，史运良.黄河输沙及其对渤海、黄海沉积作用的影响[J].地理科学，1986，6(1):1～10
14 吴世迎.黄海沉积特征的综合研究[J].海洋学报，1981，3(3):460～471
15 严钦尚.长江下游晚更新世以来河道变迁类型与机制[J].南京大学学报（自然科学版），1983，2；341～350
16 陈报章，李从先，业治铮.冰后期长江三角洲北翼沉积及环境演变[J].海洋学报，1995，17(1):62～75
17 李从先，万明浩，陈庆强.苏北沿南－三仓地区的古河谷及其地质意义[J].科学通报，1996，41（23）：2168～2170 -
点击查看大图
计量
- 文章访问数: 626
- HTML全文浏览量: 11
- PDF下载量: 474
- 被引次数: 0
下载:
