Digital image treatment applied to ichnological analysis of marine core sediments

Characterization of trace fossils in marine core sediments is, most times, difficult due to the weak differentiation between biogenic structures and the host sediment, especially in pelagic and hemipelagic facies. This problem is accentuated where a high degree of bioturbation is associated with composite ichnofabrics. Simple methods are presented here based on modifications to image features such as contrast, brightness, vibrance, saturation, exposure, lightness, and color balance using the software Adobe Photoshop CS6 (Adobe Systems, San Jose, CA, USA) to enhance visibility and thus allow for a better identification of the trace fossils. Adjustments involving brightness, levels and vibrance generally give better results. This approach was applied to marine cores of pelagic and hemipelagic sediments obtained from the Integrated Ocean Drilling Program Expedition 339, Site U1385. Enhancing the digital images facilitates ichnological analysis through improving the visibility of weakly observed trace fossils, and in some cases revealing traces not detected previously.