Age and geochemistry of igneous rocks in the Guatemalan forearc: Implications for the early history of the Caribbean Large Igneous Province

人们普遍认为，大型火成岩省是通过灾难性的岩浆事件在相对较短的时间内产生广泛的火山高原而形成的。最著名的例子之一是加勒比大火成岩省(CLIP)。然而，最近的地质年代学和地球化学研究表明，这一片段代表了几个较小的海洋高原的融合，这些高原是由加拉帕戈斯羽流头部的多个脉冲在很长时间内形成的。在dsdp第67和84段期间发现并采样的危地马拉前弧下巨大的蛇绿岩基底，可能代表了这样一个海洋高原的早期部分。我们建议对钻探样品进行详细的地质年代学、岩石学和地球化学研究，以确认1000公里长的弧前基底与夹层的可能联系。拟议的研究不仅将扩大我们对中美洲时间和大地构造历史的了解，而且将扩大我们对大型火成岩省的时代和组成的了解。更好地了解这些省份是如何形成的，将使我们能够更好地评估它们对过去全球环境和地球上生活的影响。

It is widely accepted that Large Igneous Provinces are formed through catastrophic magmatic events producing widespread volcanic plateaus within a relatively short period of time. One of the best-known examples is the Caribbean Large Igneous Province (CLIP). Recent geochronological and geochemical studies, however suggest that the CLIP represents an amalgamation of several smaller oceanic plateaus formed over long periods of time by multiple pulses of the Galápagos plume head. The vast ophiolitic basement beneath the Guatemalan forearc discovered and sampled during DSDP legs 67 and 84 could possibly represent an earlier part of such an oceanic plateau. We propose detailed geochronological, petrologic and geochemical investigations of samples from the drilling to confirm the possible affiliation of the 1000 km long forearc basement with the CLIP. The proposed study will not only expand our understanding of the temporal and geotectonic history of Central America, but also our knowledge of the age and composition of Large Igneous Provinces. A better understandig of how these provinces formed will allow us to better assess their impact on the past global enviroment and life on this planet.