GNGTS 2024 - Atti del 42° Convegno Nazionale

Session 1.3 GNGTS 2024 Strength of the lithosphere derived by geological and geophysical data: the Graham Land (Antarctc Peninsula) case study F. Linsalata 1 , D. Melini 2 , G. Spada 1 1 Dipartmento di Fisica e Astronomia (DIFA), Alma Mater Studiorum Università di Bologna, Italy 2 Isttuto Nazionale di Geofsica e Vulcanologia (INGV), Roma, Italy One-dimensional lithospheric strength is usually represented by a diagram of shear-stress versus depth (Brace, 1980), known as the Brace-Goetze strength profle, or Yield Strength Envelope (YSE). The shape of this diagram, informally dubbed the ‘Christmas tree’, strongly depends on the compositon of the consttuent rocks. This consttutve property is usually extrapolated from centmeter-sized laboratory samples (e.g. Hirth and Kohlstedf, 2003; Zhang and Karato, 1995), from structural studies of naturally deformed rocks (e.g. Twiss, 1977; Tullis, 2002; Evans, 2005), or from a larger-scale perspectve (e.g. Thatcher, 1983; Bird and Kong, 1994; Handy and Brun, 2004; Thatcher, 2009). However, the strength of the Earth's lithosphere has been debated since the beginning of the last century (Tesauro et al., 2009), when the concept of a strong lithosphere overlying a viscous asthenosphere was frst introduced (Barrell, 1914). This concept played a major role in the development of plate tectonics (Le Pichon et al., 2013), and how the strength of the plates varies spatally and temporally is a fundamental queston in geology and geodynamics (Jackson, 2002; Burov and Wats, 2006). Yield Strength Envelopes have been calculated over the last few decades for a number of locatons in Europe (e.g. Cloetngh and Burov, 1996; Cloetngh et al., 2005), America (Liu and Zoback, 1997) and Asia (Zang et al., 2007), but are not available on a regional scale for Antarctca. In this work, based on previously published data, we explore the strength of the lithosphere beneath the Graham Land region (Antarctc Peninsula, Fig. 1) using numerical modeling which simulates lithospheric deformaton as a functon of geological and geophysical parameters.