Sulfur diagenesis and burial an the Amazon shelf: Major control by physical sedimentation processes
Sulfur diagenesis and burial an the Amazon shelf: Major control by physical sedimentation processes
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DOI：
10.1007/bf01218830
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发表时间：
1996-02-01
影响因子：
2.1
通讯作者：
Blair, NE
中科院分区：
文献类型：
--
作者：
Aller, RC;Blair, NE
亚马逊陆架泥的早期成岩特性以非硫化铁和锰循环为主，与之前研究的海洋边缘环境相比，导致硫沉积相对较少。尽管硫化物矿床典型的潜在反应物丰富，但自生硫化物仅相当于成岩还原铁的 10%，DOP（黄铁矿化程度）仅相当于 0.02。 SO42-还原区以下埋藏沉积物的平均 C/S (wt wt(-1)) 比率类似于 7.4，大约是通常假设的现代陆架平均值的 2.8 的 2.6 倍。 Sigma S 的三角洲埋藏率类似于 0.65 x 10(6) 吨 yr(-1)。相对较低的西格玛 S 沉积是由陆地风化促进的，陆地风化会产生活性氧化物碎片，但显然最强烈地依赖于强烈的物理再加工和流体泥浆形成所导致的再氧化和快速掩埋。 S分布的成岩模型显示出快速的沉积物再加工（类似于表观平流的10-100 cm yr(-1)）、大量的Sigma S再氧化（84-98%），并且在一种情况下，在大约1年内沉积物沉积量高达5m厚。极低的 DOP 加上非硫化还原铁矿物占主导地位以及缺乏生物沉积结构可能是富含有机物的海洋泥浆在含氧水中进行强烈物理再加工的一个指标。
Early diagenetic properties of Amazon shelf muds are dominated by nonsulfidic Fe and Mn cycling, resulting in relatively little S deposition compared to previously studied marine margin environments. Despite abundant potential reactants typical of sulfidic deposits, authigenic sulfides represent only similar to 10% of diagenetically reduced Fe, and DOP (degree of pyritization) is only similar to 0.02. The average C/S (wt wt(-1)) ratio of buried sediment below the zone of SO42- reduction is similar to 7.4, similar to 2.6 times more than the commonly assumed modern shelf average of similar to 2.8. The deltaic burial rate for Sigma S is similar to 0.65 x 10(6) tons yr(-1). Relatively low Sigma S deposition is promoted by terrestrial weathering that delivers reactive oxide debris, but apparently depends most strongly on reoxidation and rapid burial by intense physical reworking and fluid-mud formation. Diagenetic models of S distributions demonstrate rapid sediment reworking (similar to 10-100 cm yr(-1) as apparent advection), substantial Sigma S reoxidation (84-98%), and in one case, massive sediment deposition of up to similar to 5m of sediment in similar to 1 year. Extremely low DOP coupled with , dominance by nonsulfidic reduced-Fe minerals and lack of biogenic sedimentary structures may be an indicator in marine organic-rich muds of intense physical reworking under oxygenated waters.