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Al是非常活泼的两性元素,但单质形式的自然铝也可形成和保存在特殊环境中,具有特征的地质意义.对南海269个表层样、4个柱样(165个层位)的样品进行了碎屑颗粒鉴定和统计,在5个表层样和2个柱样(3个层位)的样品中发现自然铝颗粒.自然铝颗粒为灰白色至银白色,具有强金属光泽和延展性,其形状呈不规则片状、长条状和球状.测定的自然铝为等轴晶系,Fm3m空间群,晶胞参数a值为(4.028～4.059)×10-1nm,主要由Al元素组成(95.07%～99.84%).研究揭示,自然铝是海底冷泉环境原地形成的自生矿物,是一种尚未报道的产出形式,其形成成因可能是:在冷泉区强还原和碱性的微环境下,由于微生物活动和生化酶的作用,沉积物中的Al3+被H2还原成其单质形式.因此,南海自然铝是冷泉环境中的特殊产物,填补了在冷泉区尚未发现自然铝的空白,提出的自然铝形成机理为进一步研究冷泉区特殊环境下微生物生物地球化学过程提供了基础.
Al is a very active amphipathic element, but the elemental form of natural aluminum can also be formed and preserved in a special environment, which has the characteristic geological significance.For 269 surface samples of the South China Sea, samples of 4 column samples (165 horizons) For the identification and statistics of the detritus particles, natural aluminum particles were found in the samples of 5 surface samples and 2 column samples (3 horizons) .The natural aluminum particles are gray-white to silver-white with strong metallic luster and ductility, Its shape is irregular flake, long strip and sphere.The measured natural aluminum is equiaxed, Fm3m space group, the unit cell parameter a value is (4.028 ~ 4.059) × 10-1nm, mainly composed of Al element (95.07 % ~ 99.84%). The study revealed that natural aluminum is a native mineral formed in the seabed cold spring environment and is an unreported form of production. The formation of natural aluminum may be due to the strong reduction and alkalinity in cold springs , due to microbial activity and enzymes role sediments Al3 + is H2 reduced to their elemental forms. Thus, the South China Sea natural aluminum is seep environment special product, to fill in the cold seep zone not found naturally aluminum blank, the proposed Natural aluminum formation mechanism for the further study of cold springs special ring Underlying microbial biogeochemical processes provide the foundation.