<p>Nott Corona is within Isabella Quadrangle (V-50), located 3000 km south of Atla Regio, east of Aditi Dorsa, southwest of Wawalag Planitia, and north of Nsomeka Planitia. Nott Corona has a central depression with dimensions of 110 x 80 km and a depth of about 250 m. Nott Corona has been described in the initial reconnaissance mapping of Quadrangle V-50 (e.g., [1-2]), and briefly discussed in [3]. Isabella (175 km diameter) is the second-largest impact crater on Venus and has been previously characterized in detail [4].</p> <p>The region has abundant magmatic features in addition to Nott Corona: Epon Corona, Libby Patera, Tursa Tholus, as well as graben-fissure systems. We have selected the Nott corona region for detailed (1:500,000 scale) geological mapping to produce a geological history that integrates the volcanic features (lava flows and magmatic centres) along with graben fissure systems interpreted to overlie dyke swarms (c.f. [5]).</p> <p>The focus of this abstract is our detailed mapping of the radiating graben-fissure systems in the region, and grouping of these into different swarms. Our mapping reveals the impressive radiating swarm associated with Nott corona and additional centres, and also circumferential swarms associated with Libby Patera and Epona corona, as well as additional linear swarms whose source is not yet identified, but could belong to giant radiating swarms fed from distal magmatic centres outside the study area.</p> <p>Future mapping in this area will focus on detailed mapping (1:500,000 scale) of the flows to determine their history and identify their magmatic sources, whether fissure-fed from dykes (circumferential or radial) or fed from inferred small magma chambers marked by surface collapse features [6], or fed from circular fractures associated with caldera collapse [6, 7].</p> <p><strong> </strong></p> <p><strong>References:</strong> [1] Bleamaster L.F. (2006) 37<sup>th</sup> LPSC, Abstract # 2233. [2] Bleamaster L.F. (2008) Abstr. Ann. Mtg. Planet. Geol. Mappers.  [3] Basilevsky A.T., et al. (2009) 40<sup>th</sup> LPSC, Abstract # 1827. [4] Miyamoto H., Sasaki, S. (2000) Icarus, 145, 533-545. [5] Buchan K.L. and Ernst R.E. (2021). Gond. Res., 100, 25-43.  [6] MacLellan L.M., et al. (2021). Earth-Sci. Rev., 220. 103619. [7] El Bilali H., et al. (2021). 52<sup>nd</sup> LPSC, Abstract No. 2529.</p>