What evidence is there to suggest there was a surface basalt flow rather than an intrusion?

Surface basalt flows are characterized by features such as lava tubes, flow fronts, and surface textures like pahoehoe or aa. In contrast, intrusions typically exhibit features such as chilled margins, xenoliths, and contact metamorphism. Geological mapping, petrographic analysis, and geochemical signatures can help distinguish between the two, with surface flows showing evidence of rapid cooling and interaction with the atmosphere, while intrusions tend to have slower cooling rates and minimal interaction with surface conditions. Additionally, the presence of structures like columnar jointing or vesicles can further support the interpretation of a surface basalt flow rather than an intrusion.