Study On Relation Between Seamounts Type And Crusts Mineralization

"Study on relation between seamounts type and cobalt-rich crusts mineralization" take seamounts from Mid-Pacific Mountains and Marcus-Wake ridge as research objects, aim to discuss differences in crust mineralization for different seamounts type and their mechanism, offer theoretical guidance to present crust ore-finding, ore-delineation and resources assessment. Basing on statistics of17seamounts and total96landform sections measurement, in light of seamounts morphology taxonomy, the article classify studying seamounts into two types, i.e. pointy and flat-topped seamounts, with borderline at seamount flatness f=0.25. Utilizing249survey data of our country, selecting mineralization characteristics parameters of thickness, mineral elements, types, texture&structure, mineralogy&geochemistry components of cobalt-rich crust, the article compare the differences between two types seamounts systematically, discuss their forming mechanism by integrating analysis of environmental factors, such as seamounts topography, sediment accumulation and bottom flow etc., build spatial distribution model of crust mineralization after combining research in crust growth and mineralization process, and give advise in following survey and ore-delineation of cobalt-rich crusts.The research deems mutual action of seamounts topography, sediment accumulation and bottom flow play an important role on crust mineralization, thereinto, impaction of seamounts topography on controlling crusts mineralization and spatial distribution is basically. Pointy and flat-topped seamounts different topography bring different spatial patterns of sediment accumulation and bottom flow intensity, and then produce different environmental oxidation, movements of benthic organism and suitable area of mineralization. Pointy seamounts have more intensive environmental oxidation and structure stability, developing crusts with lager thickness, more mineral-forming and biogenic elements. There are boundaries in crust growing, their formations directly relates with different nucleation potential barriers and nucleation patterns of two kinds of crust basis:concreted rock and loose sediments. Process of crusts growth and mineralization can be divided into five steps:first dispersed nucleation stage, second monomer increasing stage, third polymer forming stage, fourth porphyritic-clumpy tabular crusts stage and fifth facial (banded) tabular crusts stage. Spatially, top of seamounts always appear micronodules, only at local highland can find crusts growth and mineralization. Crust growth goes through polymer crusts and porphyritic-clumpy tabular crusts stage; evolve into continuous facial (banded) tabular crusts area from top to seamounts marginal zone. Upside slope of seamount, except for cliff, are continuous tabular crusts distribution area, when entering middle slope area, sediments coverage will increase gradually, facial (banded) tabular crusts will change into porphyritic-clumpy tabular crusts, then polymer and monomer tabular crusts, rudaceous crusts and nodule, at last go forward to micronodules intergrowth with sediments at downside and foot area of the seamount. Pointy seamounts can form ore deposit in top area, marginal zone, upside slope and ridge area of middle slope, but flat-topped seamounts basically limited in marginal zone and upside slope with exception for its cliff area.