大陆岛入海沉积物通量的估算研究

Quantifying sediment fluxes from continental shelf islands

大陆岛入海沉积物通量(Q_(s))信息对于精确解译大陆架沉积记录的研究是个重要补充。针对如何估算大陆岛Q_(s)的科学问题,本文以中国东南部海域的8227个大陆岛为例,提出了一种基于邻近大陆中小型河流Q_(s)的经验公式计算大陆岛Q_(s)的解决方案。该方案在实施时需设置两个假定,即大陆岛的Q_(s)法则遵循邻近大陆中小河流的Q_(s)法则和可将1个大陆岛当作1个河流流域计算其Q_(s)。结果表明:(1)经验公式计算的大陆岛Q_(s)为其最小估计值;如考虑大陆岛流域的具体情况,实际的Q_(s)值会稍微增加,但其增幅不超过n^(0.13)(n为流域数量);(2)经验公式能获取大陆岛Q_(s)的大致数量级信息;大陆岛的总面积为4418.49 km^(2),对应Q_(s)的数量级为10^(6) t/a,与邻近大陆中型河流入海通量的数量级相当;(3)在大河河口湾充填阶段完成以前,大陆岛沉积物是内陆架泥质沉积体的主要物源之一。因此,大陆岛入海沉积物会对大陆架沉积体系的形成和演化造成一定程度的影响,需引起研究人员的高度重视。

The information on sediment flux(Q_(s))from continental shelf islands is an important supplement to the study of accurate records interpretation of continental shelf sedimentary systems.Aiming at the scientific problem of how to estimate the Q_(s) of continental islands,this paper proposes a solution to calculate their Q_(s) based upon the empirical formula of small and medium-sized rivers in adjacent continent,taking the 8227 continental islands in Southeast China as examples.Two preconditions are set up to perform the calculation.That is,the Q_(s) rule of the continental islands follows the rule of the small and medium-sized rivers in adjacent continent,and a continental island can be treated as a river basin to calculate its Q_(s).The results show that:(1)the Q_(s) calculated by empirical formula is the minimum estimated value;if the actual basins of the continental island are taking into considered,the Q_(s) value will slightly increase,but the increase will not exceed n^(0.13)(n is the number of basins);(2)the empirical formula give the approximate magnitude information of Q_(s) for continent islands;the total area of the continental islands is 4418.49 km^(2),and the corresponding order of magnitude of Q_(s) is 10^(6) t/a;(3)during the completion of the estuarine filling stage,the continental island sediment is one of the main source for the inner continental shelf areas.Therefore,more attentions and researches are expected to the role play by the continental shelf islands to the formation and evolution of continental shelf depositional systems.