Revisão taxonômica de Myrocarpus Allemão (Leguminosae, Papilionoideae, Sophoreae) Taxonomic revision of Myrocarpus Allemão (Leguminosae, Papilionoideae, Sophoreae)

Em Myrocarpus, gênero exclusivamente sul-americano, são reconhecidas cinco espécies: Myrocarpus frondosus Allemão, M. leprosus Pickel, M. venezuelensis Rudd, M. fastigiatus Allemãoe M. emarginatus A.L.B. Sartori & A.M.G. Azevedo. Na delimitação das espécies são discutidos dados de morfologia, hábitats e de distribuição geográfica. A morfologia das pétalas e a ornamentação da região seminífera são caracteres relevantes na identificação das espécies, embora não utilizados até o presente. Este estudo apresenta chave de identificação das espécies, descrições, ilustrações, mapa de distribuição e novos registros de ocorrência.<br>In Myrocarpus, an exclusively South American genus, five species are recognised: Myrocarpus frondosus Allemão, M. leprosus Pickel, M. venezuelensis Rudd, M. fastigiatus Allemãoand M. emarginatus A.L.B. Sartori & A.M.G. Azevedo. Morphologic data, habitat information and geographic distribution of each taxon are discussed. Petal morphology and ornamentation of seed chamber are an important character for species identification, though not shown previously. Key to the species, descriptions, illustrations, distribution, and new registers are presented

Testing reproducibility of vitrinite and solid bitumen reflectance measurements in North American unconventional source-rock reservoir petroleum systems

An interlaboratory study (ILS) was conducted to test reproducibility of vitrinite and solid bitumen reflectance measurements in six mudrock samples from United States unconventional source-rock reservoir petroleum systems. Samples selected from the Marcellus, Haynesville, Eagle Ford, Barnett, Bakken and Woodford are representative of resource plays currently under exploitation in North America. All samples are from marine depositional environments, are thermally mature (T >445 °C) and have moderate to high organic matter content (2.9–11.6 wt% TOC). Their organic matter is dominated by solid bitumen, which contains intraparticle nano-porosity. Visual evaluation of organic nano-porosity (pore sizes 1.0 produced lowest R values, generally ≤0.5% (absolute reflectance), similar to a prior ILS for similar samples. Other traditional approaches to outlier removal (outside mean ± 1.5*interquartile range and outside F10 to F90 percentile range) also produced similar R values. Standard deviation values < 0.15*(VR or BR) reduce R and should be a requirement of dispersed organic matter reflectance analysis. After outlier removal, R values were 0.1%–0.2% for peak oil thermal maturity, about 0.3% for wet gas/condensate maturity and 0.4%–0.5% for dry gas maturity. That is, these R values represent the uncertainty (in absolute reflectance) that users of vitrinite and solid bitumen reflectance data should assign to any one individual reported mean reflectance value from a similar thermal maturity mudrock sample. R values of this magnitude indicate a need for further standardization of reflectance measurement of dispersed organic matter. Furthermore, these R values quantify realistic interlaboratory measurement dispersion for a difficult but critically important analytical technique necessary for thermal maturity determination in the source-rock reservoirs of unconventional petroleum systems.This research was funded by the USGS Energy Resources Program