摘要
洛亚蒂盆地沉积物是棕黄色软泥和生物碎屑砂。它们有5个来源:新喀里多尼亚、堤礁、深海生物群落、浮游生物群体和火山碎屑。沉积物由浊流和半深海沉积物的互层组成,可以通过粒度分析,矿物成分和生物碎屑的分析将两者加以区分。通过对蒂奥和利富之间的岩心的研究,认识到在蒂奥水道对面,分布着一个展布广阔,但幅度很小、延伸50Km的海底扇。
The diverse date (submarine topographic maps, bathymetric, profiles, piston and box cores)collected across the New Caledonian slope, the Lifou slope and in the Loyalty basin during thesurvey BIOCAL, 1985, are used. to restore the modern sedimentary environment. The recovered sediments, are beige to brown-yellowish mud and bioclastic sands and silts. Allthe sediments originated from five sources: 1) New Caledonian land (quartz, clay, heavy minerals);2) the barrier reef (fragment of algae, foraminifera and peri-platform ooze); 3) the bathyalcommunity (diverse bioclasts); 4) the plankton community (foraminifera, coccolithus and pteropoda);5) pyroclastic fragments of volcanic origin. The sediments are bioturbated and generally composed of interbeded turbidited and hemipelag.ites which can be distinguished by the grain size variation curves. the mineralogy, the proportionsof the main biologic components and the colour. The presence of turbidites between Thio and Lifou suggests the existence of a low profilesubmarine fan fed by the main conyons of the slope opposite the pass of Thio.
关键词
盆地
沉积作用
ophiolite
turbidity flow
hemipelagic sediment
submarine fan
barrier reef
sedimentary environent
