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测区沉积物和间隙水小的氟含量(分别为200～395μg/g和1.18～1.92μg/ml)均远低于所报道的大洋区域平均值(分别约为540μg/g和2.7μg/ml)。研究结果表明,测区沉积物中氟含量分布主要受周围岛屿风化基岩的化学成分制约;沉积物中主要含氟矿物:萤石/磷灰石、黄玉、黑云母等含量极低,氟在沉积物中赋存的矿物相主要与角闪石[AX_2Y_5Z_8O_(22)(OH·F)_2]有关。氟含量与碎屑矿物中角闪石的体积比间的关系式可大致表示为:氟含量=217+361nV_H;间隙水中的低氟主要由测区化学风化不发育及氟的钙盐沉积所致。此外,沉积物中强阴离子(HCO_3~-)可交换态含量仅约为太平洋(亦道附近)的1/10、中国南海的1/4和浙江东部沿海的1/2,也反映了测区沉积物中易参与固-液相交换的氟离子含量较低,由此也必将导致间隙水中的低氟。沉积有机质的分解对间隙水的氟含量有一定的贡献,但这种氟易于为沉积物固相所捕获。测区沉积体系中氟的固-液相转换与分配机制可初步描述为: 有机质(氟)垆苎些苎苎苎蟹间隙,k苎苎苎些苎竺些鱼坚固相 (氧化物) 还原 一”—— ,一”
Fluorine contents (200-395 μg / g and 1.18-1.92 μg / ml, respectively) for the sediment and interstitial water in the study area were much lower than the reported mean values for the oceanic area (about 540 μg / g and 2.7 μg / ml, respectively ). The results show that the distribution of fluoride in the sediments of the survey area is mainly controlled by the chemical composition of the weathered bedrock of the surrounding islands. The content of the major fluorite minerals in the sediments: fluorite / apatite, topaz, biotite is extremely low, The mineralized phases in the sediments are mainly related to amphibole [AX_2Y_5Z_8O_ (22) (OH · F) _2]. The relationship between fluorine content and volume ratio of amphiboles in detrital minerals can be broadly expressed as: fluorine content = 217 + 361nV_H; low fluorine in interstitial water is mainly caused by undeveloped chemical weathering and calcium deposition of fluoride . In addition, the exchangeable content of strong anions (HCO 3 -) in the sediments is only about 1/10 of that in the Pacific Ocean (near the central part of the country), and 1/4 of the South China Sea and 1/2 of the eastern coast of Zhejiang also reflect the measured area Sediment easy to participate in solid - liquid exchange of fluoride ion content is lower, which will inevitably lead to interstitial low fluorine. The decomposition of sedimentary organic matter has a certain contribution to the fluorine content of interstitial water, but this kind of fluorine tends to be trapped in the solid phase of the sediment. The mechanism of fluorine solid-liquid phase conversion and partitioning in the depositional sedimentation system can be described as follows: organic matter (fluorine) 垆 苎 些 some 苎 ramie ramie crab gap, k 苎 ramie ramie ramie ramie some fish solid phase (oxide) “-- ,one”