An analysis of the petrophysical and diagenetic effects of the emplacement of Cretaceous basaltic lava flows (Serra Geral Formation) on aeolian sandstones (Botucatu Formation) has been undertaken on core samples from the Paraná Basin, Brazil. Between 0.1 and 1 m from the contact zone, acoustic wave velocities and porosities in sandstones show a significantly wider scatter than those located >1 m away from the lava contact. Higher P-wave values (average 3759.3 m s^–1) occur between 0.1 and 1 m from the lava contact in contrast to those areas >1 m away (average 3376.8 m s^–1), whilst the average porosity is 6.5% near the contact (0.1–1 m) and 10.7% away from the contact (>1 m). Petrographical evaluation reveals two diagenetic pathways responsible for modification of the petrophysical properties: early hydrothermal Mg-rich authigenesis (Type 1) and early chemical dissolution (Type 2). Type 3 diagenesis occurs away from the lava–sediment contact (>1 m), with the appearance of poikilitic calcite and smectite. The sandstone samples associated with Type 1 and Type 2 diagenesis display a decrease in porosity and increased acoustic velocities in relation to Type 3, while Type 3 samples show little or no variation in reservoir properties. The lava-induced diagenetic effects at the sandstone–lava contacts (0.1–1 m) may form a baffle or seal to fluids around the margins of the sandstone bodies. Therefore, whilst diagenesis associated with lava emplacement may hinder reservoir quality around the margins, the original reservoir properties are preserved within these large sandstone bodies.

Supplementary material: Petrophysical and petrographical data are available at https://doi.org/10.6084/m9.figshare.c.5244473

已经对巴西巴拉那盆地的岩心样品进行了白垩纪玄武岩熔岩流（塞拉热拉尔组）对风沙砂岩（博图卡图组）的岩石物理和成岩作用的分析。在距离接触区0.1至1 m的范围内，砂岩中的声波速度和孔隙度显示出比距熔岩接触点> 1 m处的声波速度和孔隙度明显更宽的散射。更高的P波的值（平均3759.3米小号^-1）0.1至1米之间发生从与那些区域>熔岩触点1米的距离（平均3376.8米小号^-1），而在接触点（0.1-1 m）附近的平均孔隙率为6.5％，而在接触点（> 1 m）附近的平均孔隙率为10.7％。岩相学评价揭示了造成岩石物性改变的两个成岩途径：早期热液富含镁的自生作用（类型1）和早期化学溶解（类型2）。3型成岩作用发生在远离熔岩-沉积物接触（> 1 m）的地方，并出现了方解石方解石和蒙脱石。与1型和2型成岩作用有关的砂岩样品相对于3型显示出孔隙度降低和声速增加的趋势，而3型采样显示出储层性质的变化很小或没有变化。砂岩-熔岩接触（0.1-1 m）处熔岩引起的成岩作用可能对砂岩体边缘周围的流体形成挡板或密封。所以，

补充材料：岩石物理和岩石学数据可在https://doi.org/10.6084/m9.figshare.c.5244473上获得。