Latitudinal variability of preserved sedimentary organic matter along the Peruvian continental margin as inferred from petrographic and geochemical properties

Processes controlling preservation and accumulation of organic matter (OM) in marine sediments are highly sensitive towards both natural anthropogenic impacts. Thus, the sedimentary OM is considered a key proxy for characterization recent past environments . Along Peruvian continental margin (PCM), high primary production an intense oxygen minimum zone (OMZ) favor sediments. Spatial variations oceanographic conditions impact on productivity redox , particular OMZ intensity. These factors turn lead to spatial differences depositional preservation. Therefore, this study aims at characterizing nature types along PCM covering wide latitudinal bathymetric range. With purpose, total 29 surface sediment samples were collected from Tumbes (3°S) San Juan (15°S) analyzed by means petrography (palynofacies analysis) Rock-Eval pyrolysis. Results allowed PCM, predominantly amorphous, revealing its overwhelming origin. The highest abundances gelified amorphous OM, carbon S1 S2 fractions occurred southern part area, especially off Callao (12°S) Pisco (14°S), important upwelling centers. A principal component analysis performed description main In outer shelf well-preserved occurs whereas inner oscillations less pyrite formation North Callao, Huacho (11°S), mixed signal was observed. Finally, slope, transportation processes seem play role accumulation. This also evaluation certain proxies (e.g. hydrogen index index) routinely used palaeoceanographic studies. • Characterization margin. Organic areas zone. Low settings. Transport affect slope