Hydrothermal plumes along the East Pacific Rise, 8°40′ to 11°50′N: Particle distribution and composition
Hydrothermal plumes along the East Pacific Rise, 8°40′ to 11°50′N: Particle distribution and composition
复制标题
北纬 8°40′ 至 11°50′ 沿东太平洋海隆的热液羽流：颗粒分布和成分
DOI：
10.1016/0012-821x(94)90023-x
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发表时间：
1994
影响因子：
5.3
通讯作者：
G. Lebon
中科院分区：
文献类型：
--
作者：
R. Feely;J. Gendron;E. Baker;G. Lebon
在东太平洋海隆（EPR）北纬9° 45.52′处发现的火山喷发使我们研究了如何在水面船舶调查期间利用热液羽流中悬浮物的组成来更好地了解脊顶系统的相对年龄和喷口流体特征。在TROUGHS（水下地球化学热液信号的热带海岭观测）考察期间，我们沿克利珀顿转换断层以北和以南EPR的约8° 40′ N至11° 50′ N的350 km剖面沿着收集了热液羽流颗粒。在克利珀顿转换断层以南的部分，颗粒中的S Fe比范围约为0.9至10，最高值位于9° 45.52′ N的新喷口区。这些富集与同一喷流场中烟羽中3 He/heat和CH 4 Mn比值的升高完全一致。富含硫的颗粒主要是有机物，可能与火山爆发相关的“细菌暴风雪”有关。此外，非常高的铜-铁和锌-铁的比例观察到的热液羽南部的克利珀顿转换断层。这些高比率表明在9° 35′ N和9° 50′ N之间的高温、富H2S喷口占优势。相比之下，样品的部分北部的克利珀顿转换断层的S-Fe比值范围从0.04至0.82，典型的成熟，富铁热液羽。这些结果表明，在9° 45.52′ N站点的富气喷口流体产生的水柱中的富硫颗粒。在1986年胡安·德富卡海岭（JdFR）的巨型羽流下面也观察到了富含气体的羽流和富含硫的羽流颗粒，这表明了类似的形成模式。北克利珀顿转换断层，热液颗粒占主导地位的富铁羟基氧化物颗粒，成熟的高温喷口领域的特点。烟羽最大中心位于11° 08′ N。Fe羟基氧化物颗粒从海水中除去Ca、Si、P、V、Cr和As。对于P和V，EPR热液颗粒中的平均元素/Fe比介于JdFR和TAG热液系统之间。对于作为所有三个系统的平均元素/Fe比是相同的。硅清除热液铁羟基氧化物颗粒的新证据表明，这在海洋中溶解的硅汇是小的。
The discovery of a volcanic eruption at the 9° 45.52′ N site on the East Pacific Rise (EPR) led us to investigate how the composition of suspended matter in hydrothermal plumes may be used to provide a better understanding of the relative age and vent fluid characteristics of a ridge crest system during surface ship surveys. During the TROUGHS (Tropical Ridge Observations of Underwater Geochemical Hydrothermal Signals) expedition we collected hydrothermal plume particles along a 350 km section, extending from approximately 8° 40′ N to 11° 50′ N, of the EPR north and south of the Clipperton Transform Fault. Over the segment south of the Clipperton Transform Fault, the S Fe ratio in the particles ranged from about 0.9 to 10, with the highest values immediately over the new vent field at the 9° 45.52′ N site. These enrichments exactly coincide with the elevated 3 He/heat and CH 4 Mn ratios in the plumes over the same vent field. The S-rich particles are primarily organic and may be related to the ‘bacteria blizzard’associated with the eruption. In addition, very high Cu Fe and Zn Fe ratios were observed in the hydrothermal plumes south of the Clipperton Transform Fault. These high ratios are indicative of the predominance of high-temperature, H 2 S-rich vents between 9° 35′ N and 9° 50′ N. In contrast, the samples from the segment north of Clipperton Transform Fault had S Fe ratios which ranged from 0.04 to 0.82, typical of mature, Fe-rich hydrothermal plumes. These results suggest that the gas-rich vent fluids at the 9° 45.52′ N site produced the sulfur-enriched particles in the water column. Gas-rich plumes and sulfur-enriched plume particles were also observed underneath the 1986 Megaplume on the Juan de Fuca Ridge (JdFR), suggesting a similar mode of formation. North of the Clipperton Transform Fault, the hydrothermal particles are dominated by Fe-rich oxyhydroxide particles, characteristic of mature high-temperature vent fields. The plume maximum is centered at 11° 08′ N. The Fe oxyhydroxide particles scavenge Ca, Si, P, V, Cr and As from seawater. For P and V the mean element/Fe ratios in the EPR hydrothermal particles are intermediate between JdFR and TAG hydrothermal systems. For As the mean element/Fe ratios of all three systems are about the same. New evidence for Si scavenging by hydrothermal Fe oxyhydroxide particles indicates that this sink for dissolved Si in the oceans is small.