THE SEDIMENTARY RECORD OF RECENT TAUGHT ST. SIMÓN (RIA OF VIGO, NORTHWESTERN SPAIN): INTERACTION BETWEEN NATURAL PROCESSES AND HUMAN-INDUCED ACTIVITIESAuthor:
ÁLVAREZ IGLESIAS PAULA.
Year: 2005.
University:
VIGO.
Place of defense: FACULTAD DE CIENCIAS DEL MAR.
Place of preparation: FACULTAD DE CIENCIAS.
Summary: This research work has been studied variability of the geochemical characteristics and sedimentológicas in the sedimentary record of the intertidal and subtidal areas of Ensenada San Simon. Based on the characterization and interpretation of sedimentary architecture of the intertidal zone of the creek has described the evolution of sedimentary area for the last 6000 years. This shows the alternating facies channel estuárica and facies plain international climate change and related processes autocíclicos. Using isotopic dating techniques have been established rates of sedimentation and taught in the chronology of metal pollutants contribute to sediment. It has demonstrated the need for detailed geochemical analysis in parallel to the donation by 210Pb and 137Cs in order to obtain reliable sedimentation rates in sandy sediments of non-homogeneous texture. We have identified different sources metal (detríticas, biogenic and anthropogenic) in the intertidal and subtidal areas dela inlet. The greatest impact of various anthropogenic activities is produced from the mid-twentieth century due to urban and industrial development dela Ria de Vigo and its environs. They have generated an increase in contributions from fine-grained particles from the wastewater discharges and input typically anthropogenic trace metals. The degree of contamination to the recent sedimentary record is ranked low to moderate for As, Cr, Cu and Zn, and a liberal to very high for Pb. The main source of PB to the cove is a ceramic industry are secondary while emissions from vehicles. Most of the trace metals are in the residual fraction, and thus do not constitute an environmental hazard high, except for the case of PB. For this element concentrations in the fractions more bioavailable exceed by several orders of magnitude the background levels of the study area. The evolution diagnética postdeposiconal delos sediment has been established through the study of the variation of the system CS-Fe and their mutual relationship, in combination with the evaluation of the influence of the sources of organic matter processes diagenéticos observed. The processes of early diagénesis are intense because of the high content of organic matter in sediments, which are due to the contributions continental wealth in marine flora (phanerogams, algae), the biological productivity (crops marine alforamientos) and downloads wastewater. In addition, it has been determined the usefulness of various geochemical indicators, such as the degree of prititizaicón (PDO) and the degree of piritización of trace metals (DTMP) as indicators of redox state and the quality of the sediment, with a special emphasis on the role of gracious pyrite trace metals such as warehouse and the potential for mobility in these areas of aquaculture. From these indexes and relations CS-Fe has established a model zoning diagenética for sediments from areas within estuaries. It identifies areas (1), óxica, (2) subóxica (3) anóxica-sulfídica and (4) anóxica-no sulfídica whose length (cm-m) depends on the texture of sediment (zone 1), the depth columns of water and the process that generate a remobilization of the sediments (zone 2) the degree of reactivity of organic matter (intertidal area) or the depletion of sulfate ions with depth (area submarea) (zone 3) and the presence of organic matter metabolizable (zone 4).
