Fluid seepage at the continental margin offshore Costa Rica and southern Nicaragua
Fluid seepage at the continental margin offshore Costa Rica and southern Nicaragua
复制标题
哥斯达黎加和尼加拉瓜南部近海大陆边缘的流体渗漏
DOI：
10.1029/2008gc001978
复制
发表时间：
2008
期刊：
影响因子：
3.7
通讯作者：
E. Suess
中科院分区：
文献类型：
--
作者：
H. Sahling;D. Masson;C. Ranero;V. Hühnerbach;W. Weinrebe;I. Klaucke;D. Bürk;W. Brückmann;E. Suess
在尼加拉瓜南部近海和哥斯达黎加中北方太平洋大陆边缘（一个以俯冲侵蚀为特征的会聚边缘），对海底富甲烷流体渗漏进行了系统的搜寻。使用多波束测深、侧扫声纳图像、电视雪橇观测和采样的组合发现了100多个流体渗漏。这相当于大陆坡平均每沿着4公里就有一个渗漏点。在研究区域的西北部，东太平洋隆起形成的洋壳俯冲的特征是普遍的弯曲引起的海洋板块断层和相对均匀的上覆大陆边缘形态。边缘这一部分的渗漏通常发生在高50 - 100 m、底部宽达1 km的近似圆锥形土丘处。在240公里长的边缘部分发现了60多个这样的土丘。一些正断层也有局部渗流。相比之下，在东南部，覆盖在科科斯-纳斯卡扩张中心形成的洋壳上的220公里长的边缘部分具有相对更不规则的形态，主要是由位于海洋板块上的脊和海山的俯冲造成的。在这部分边缘上有40多处渗漏。该边缘段形态不规则，具有多种渗漏构造。渗漏与滑坡疤痕、海山俯冲相关的断裂、土丘和断层有关。侧扫图像中的几个反向散射异常没有明显的起伏，可能与碳酸盐沉淀有关。探测到的流体渗漏在整个边缘上分布不均匀，但出现在以海沟向陆方向28 ± 7 km为中心的大致边缘平行带中。这种分布表明，渗漏可能被供给到从板块边界沿沿着穿透深部断层上升的流体中，这些断层穿过上部板块。
A systematic search for methane‐rich fluid seeps at the seafloor was conducted at the Pacific continental margin offshore southern Nicaragua and northern central Costa Rica, a convergent margin characterized by subduction erosion. More than 100 fluid seeps were discovered using a combination of multibeam bathymetry, side‐scan sonar imagery, TV‐sled observations, and sampling. This corresponds, on average, to a seep site every 4 km along the continental slope. In the northwestern part of the study area, subduction of oceanic crust formed at the East Pacific Rise is characterized by pervasive bending‐induced faulting of the oceanic plate and a relatively uniform morphology of the overriding continental margin. Seepage at this part of the margin typically occurs at approximately cone‐shaped mounds 50 ‐ 100 m high and up to 1 km wide at the base. Over 60 such mounds were identified on the 240 km long margin segment. Some normal faults also host localized seepage. In contrast, in the southeast, the 220 km long margin segment overriding the oceanic crust formed at the Cocos‐Nazca Spreading Centre has a comparatively more irregular morphology caused mainly by the subduction of ridges and seamounts sitting on the oceanic plate. Over 40 seeps were located on this part of the margin. This margin segment with irregular morphology exhibits diverse seep structures. Seeps are related to landslide scars, seamount‐subduction related fractures, mounds, and faults. Several backscatter anomalies in side‐scan images are without apparent relief and are probably related to carbonate precipitation. Detected fluid seeps are not evenly distributed across the margin but occur in a roughly margin parallel band centered 28 ± 7 km landward of the trench. This distribution suggests that seeps are possibly fed to fluids rising from the plate boundary along deep‐penetrating faults through the upper plate.
哥斯达黎加汇聚边缘间歇性活动泥火山的原位底栖通量
影响因子：
5.3
作者：
Linke P;Wallmann K;Suess E;Hensen C;Rehder G
通讯作者：
Rehder G
影响因子：
3.7
作者：
C. Ranero;I. Grevemeyer;H. Sahling;U. Barckhausen;C. Hensen;K. Wallmann;W. Weinrebe;P. Vannucchi;R. Huene;K. Mcintosh
通讯作者：
C. Ranero;I. Grevemeyer;H. Sahling;U. Barckhausen;C. Hensen;K. Wallmann;W. Weinrebe;P. Vannucchi;R. Huene;K. Mcintosh