Terrestrial laser scanner imaging reveals astronomical forcing in the Early Cretaceous of the Tethys realm

We present the first application of the terrestrial laser scanner (TLS) to cyclostratigraphy and demonstrate the capability of this remote sensing technology in rapid retrieval of high resolution cyclostratigraphic data from typical hemipelagic successions exposed in outcrops with limited accessibility. TLS infrared imaging is capable of recording, up to a distance of 50. m, a laser intensity value which is inversely proportional to the abundance of clay minerals in limestones and marls. The following characteristics make TLS a very useful tool: 1) fast data collection; 2) high-resolution and high accuracy; and 3) TLS is an active, sensor-based acquisition process that is independent from environmental conditions as illumination. We demonstrate this new methodology with a study of a section in the Early Cretaceous (Albian) Marne a Fucoidi formation exposed in the Vispi Quarry near Gubbio (central Italy). The same stratigraphic interval has been studied in detail in a core drilled at a few kilometers away (the Piobbico core). We compare TLS results with those obtained previously from the Piobbico core, and propose a correlation between the two sections. Results indicate clear cyclicity in the TLS data, that correlates to the Piobbico data. This is the first report of correlation at the eccentricity scale in pre-Cenozoic stratigraphy. Statistical time series analysis confirms the presence of astronomical parameters with a predominance of eccentricity cycles, in agreement with the Piobbico core. The future application of TLS in cyclostratigraphy will rapidly enrich the collection of series with Milankovitch cycles needed to build a Mesozoic astrochronological time scale.