Analysis of the geometry of diabase sills of the Serra Geral magmatism, by 2D seismic interpretation, in Guareí region, São Paulo, Paraná basin, Brazil

ABSTRACT: The Paraná Basin holds in its stratigraphic record a thick layer of volcanic rocks related to the opening of the Gondwana Supercontinent, which occurred during the Eocretaceous. Based on the interpretation of three two-dimensional (2D) seismic lines in the region of Guareí, East-Central São Paulo state, in the Southeast of Brazil, the subsurface geometries of these volcanic rocks were identified. Since the original seismic resolution quality was low, alternative techniques were utilized to improve the seismic imaging, such as isolating maximum and minimum amplitude values by manipulating the color scale, and using the root mean square (RMS) attribute and the Amplitude Volume technique (tecVA), which emphasize the seismic signature of igneous rocks in relation to sedimentary layers. The use of such techniques allowed the identification of different geometries of diabase sills and showed a relationship between these intrusive and organic matter maturation of the source rock.

摘要：巴拉那盆地（Paraná Basin）的地层记录中保存有与早白垩世（Eocretaceous）冈瓦纳超大陆（Gondwana Supercontinent）裂解事件相关的厚层火山岩。本研究基于巴西东南部圣保罗州中东部瓜雷伊（Guareí）区域内的三条二维（2D）地震测线解释成果，识别出了该套火山岩的地下几何形态。鉴于原始地震分辨率质量不佳，研究采用了多项辅助技术以优化地震成像效果：包括通过调整色标分离最大、最小振幅值，以及使用均方根（RMS）属性与振幅体积技术（tecVA），以此强化火成岩相较于沉积岩层的地震响应特征。上述技术的应用不仅识别出了多种辉绿岩床的几何形态，还揭示了此类侵入岩体与烃源岩有机质成熟度之间的关联。