geologia e recursos naturais

Remote detection and mapping of surface materials using optical sensors relies predominantly on analyzing multispectral and hyperspectral imagery employing classification algorithms. The classification process involves comparing the spectra of individual pixels within the image to spectra from reference databases, commonly referred to as spectral libraries. Here, we introduce a comprehensive compilation of spectral libraries specifically tailored for petroleum hydrocarbons (PHC), meticulously crafted under controlled laboratory conditions.

Abstract

As anomalias de gadolínio são reconhecidas atualmente como bons marcadores de poluição causada por água residuária. Apesar disso, ainda não existe um método padronizado para a sua estimativa. Neste artigo são comparadas quatro equações, diferentes limiarese diferentes valores de normalização para estimativa das anomalias de Gd em um estudo de caso realizado em um aquífero aluvionar onde existem sistemas de saneamento in-situ.

Recognizing the deposits of linear megadunes in ancient aeolian successions is challenging when the original bedform topography is not preserved. The present study provides a detailed analysis of the depositional architecture of an ∼ 80 m-thick interval of the Mesoproterozoic Galho do Miguel Formation (SE Brazil) to reconstruct the original morphologies of linear megadunes and to understand their dynamics. The depositional architecture reveals compound cross-bedded sets, which transition laterally into thick low-angle cross-stratified sets and planar-parallel sandstone beds.

The Neoproterozoic phosphogenic event records biotic and biogeochemical changes that seem to indicate intrinsic relationships between phosphogenesis and phosphatic fossil preservation. However, chemo-litho and biostratigraphic correlations conducted on fossiliferous, phosphatic successions of the Doushantuo Formation, South China, evidence a highly heterogeneous record, featuring diachronic depositional ages, variable taxonomic diversity and inconsistent, “noisy” δ13C records.

Abstract

This study highlights a new by-product source for cobalt by recycling Paleoproterozoic Mn deposits. We present a geochemical modeling approach utilizing Principal Component Analysis (PCA) for available geochemical data of Paleoproterozoic manganese deposits found in Africa and Brazil, which exhibit anomalous cobalt contents (up to 1200 ppm) along with other metals such as copper, nickel, and vanadium.

The Ediacaran-Cambrian transition documents a critical stage in the diversification of animals. The global fossil record documents the appearance of cloudinomorphs and other shelled tubular organisms followed by non-biomineralized small carbonaceous fossils and by the highly diversified small shelly fossils between ~ 550 and 530 Ma.