Intraplate strike-slip faulting in East Antarctica: new geophysical views from the Rennick Graben and Wilkes Subglacial Basin

Intraplate strike-slip faulting can occur in association with different geodynamic settings, ranging from subduction-related to collision and extension. Geological and geophysical research in Northern Victoria Land (NVL) in East Antarctica, has led to the interpretation that major fault systems that were active during the early Paleozoic Ross Orogen were reactivated much later as right-lateral intraplate strike-slip fault systems from ca 48 Ma, and that these faults may have accomodated differential shear along evolving oceanic transform faults located between southeastern Australia and Tasmania. One of the main structures in NVL that has been inferred to relate to this unusual geodynamic process is the Rennick Graben (RG), but its age, extent and kinematics have remained both poorly constrained and controversial. Even less well-understood are the potential tectonic linkages between the RG and the deep sub-basins that lie within the much broader Wilkes Subglacial Basin (WSB), in the hinterland of the Transantarctic Mountains. Here, we present new interpretations of enhanced potential field images derived from aeromagnetic and airborne and land-gravity observations to help constrain the extent and architecture of the RG and the sub-basins within the WSB. We show that the RG is a composite pull-part basin that extends from the Oates Coast towards the margin of the Ross Sea Rift, part of the West Antarctic Rift System. We suggest that the more cratonic WSB region was also affected by extensional and transtensional processes, the latter potentially linked to an evolving and distributed left-lateral Paleogene(?) strike-slip plate boundary between East Antarctica and Australia

Capturing player enjoyment in computer games

The current state-of-the-art in intelligent game design using Artificial Intelligence (AI) techniques is mainly focused on generating human-like and intelligent characters. Even though complex opponent behaviors emerge through various machine learning techniques, there is generally no further analysis of whether these behaviors contribute to the satisfaction of the player. The implicit hypothesis motivating this research is that intelligent opponent behaviors enable the player to gain more satisfaction from the game. This hypothesis may well be true; however, since no notion of entertainment or enjoyment is explicitly defined, there is therefore no evidence that a specific opponent behavior generates enjoyable games.peer-reviewe

New Zinc-Based Active Chitosan Films: Physicochemical Characterization, Antioxidant, and Antimicrobial Properties

The improvement of the antioxidant and antimicrobial activities of chitosan (CS) films can be realized by incorporating transition metal complexes as active components. In this context, bioactive films were prepared by embedding a newly synthesized acylpyrazolonate Zn(II) complex, [Zn(QPhtBu)2(MeOH)2], into the eco-friendly biopolymer CS matrix. Homogeneous, amorphous, flexible, and transparent CS@Znn films were obtained through the solvent casting method in dilute acidic solution, using different weight ratios of the Zn(II) complex to CS and characterized by powder X-ray diffraction (PXRD), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR), Raman, and scanning electron microscopy (SEM) techniques. The X-ray single-crystal analysis of [Zn(QPhtBu)2(MeOH)2] and the evaluation of its intermolecular interactions with a protonated glucosamine fragment through hydrogen bond propensity (HBP) calculations are reported. The effects of the different contents of the [Zn(QPhtBu)2(MeOH)2] complex on the CS biological proprieties have been evaluated, proving that the new CS@Znn films show an improved antioxidant activity, tested according to the DPPH method, with respect to pure CS, related to the concentration of the incorporated Zn(II) complex. Finally, the CS@Znn films were tried out as antimicrobial agents, showing an increase in antimicrobial activity against Gram-positive bacteria (Staphylococcus aureus) with respect to pure CS, when detected by the agar disk-diffusion method

Deciphering the sub-ice basement architecture of the Rennick-Aviator fault zone: insight from outcrop scale fracture analysis.

The northern termination of the Transantarctic Mts in North Victoria Land is characterized by a complex architecture deriving from long-lived tectonic activity along major crustal shear zones that have been reactivated several times until Recent. These are both first-order faults, which separate the Wilson, Bowers and Robertson Bay crustal blocks, and second-order faults which cut through homogeneous lithotectonic units. Rennick Graben Fault (RGF) system and Aviator Fault (AF) represent a NW-SE shear corridor with along-strike length of about 400 km that connects to the kinematics of the fracture zones in the Southern Ocean (between Australia and East-Antarctica) and to the extensional tectonics in the Ross Sea embayment. In this contribution we present the analyses of structural data measured in the fault corridor of the RGF and AF to highlight i) the geometry/link of their connection, and ii) their Meso-Cenozoic poly-phased tectonic activity. Brittle deformation measured in the field includes faults with the associated kinematic indicators, fracture attitude, dimension (H) and spacing (S). This deformation involves rocks with ages ranging from Lower Paleozoic to Lower Jurassic. The intensity of brittle deformation is quantified by the H/S dimensionless parameter and its spatial distribution in the study area relates to the local stress produced by the kinematics of RGF and AF. The (multiple) paleostress are computed by an original methodology that includes the inversion of both faults and near orthogonal fracture systems. Results confirm the Meso-Cenozoic strike slip-kinematics of the RGF-AF characterized by a right-lateral event that followed an older left-lateral one

3D Modelling of Late Quaternary coastal evolution between Albenga and Loano (Western Liguria, Italy)

Seismic lines and sediment cores collected along the shelf between Albenga and Loano (Liguria, NW Italy) allowed an unprecedented reconstruction of the characters and distribution of late Quaternary transgressive littoral deposits. Multiple seismic lines datasets and stratigraphic logs were managed within a single, GIS-based software. This approach allowed the merging, analysis, and interpretation of multimethodological datasets, greatly increasing the understanding of the study area. On seismic reflection lines, the identification of high-amplitude acoustic facies (i.e. coarse-grained deposits), coupled with the analyses of the identified paleo-morphologies, allowed the mapping of (at least) five paleo shorelines along the continental shelf at 30-40 40-60, 60-80, 80-90 and 90-100 m below sea level. Their retrogradiational geometry and terraced distribution likely indicate episodic, stepwise retreats of Late Quaternary coastal system (last 18-11 Ky), compatible with phases of fast sea level rise interspersed by long periods of sea level stillstand

Fault-related fractures of the Rennick-Aviator shear zone (north Victoria Land, Antarctica): insight to infer the paleo fluid circulation.

North Victoria Land (NVL), located at the Pacific-Southern Ocean termination of the Transantarctic Mountains (TAM), presents a complex architecture deriving from a long-lasting tectonic evolution. After the Paleozoic juxtaposition to the East Antarctic craton, NVL was affected by i) the Gondwana breakup which led to the Meso-Cenozoic rifting-drifting between Antarctica and Australia, ii) the rifting in the Ross Sea, iii) the uplift of the TAM and iv) the SE prosecution of the kinematics that characterize the spreading of the Southern Ocean (e.g., Tasman and Balleny Fracture Zone). Regionally sized, crustal scale faults crosscut VL from the Southern Ocean to the Ross Sea and represent Paleozoic inherited weakness zones that have been reactivated several times until Recent. These are both firstorder faults, which separate different crustal blocks (from W to E, the Wilson, Bowers, and Robertson Bay terranes), and second-order faults that cut through homogeneous lithotectonic units. This long-lived tectonic history produced zones of intense deformations, often accompanied with fluid circulations (e.g., Malatesta et al., 2021) and exhumation of deep shear zones. In this work we present preliminary results of the analysis of fractures associated to the Rennick-Aviator km-scale fault corridor. Specifically we explore the intensity of brittle deformation, its spatial distribution and relation with the regional faults aimed to quantify the spatial variation of the hydraulic properties (e.g., secondary permeability) of the damage zones. Moreover, fault and fracture inversion for paleostress computation is applied to infer the most permeable fracture population (e.g., fracture kept open from the acting paleostress that increases the secondary permeability in a specific direction and thus enhance fluid circulation along preferential pathways). In NVL various fault zones are characterized by hydrothermal mineral alteration (e.g., Crispini et al., 2011; Malatesta et al., 2021) this study represents the basis to identify the main fluid pathways and to estimate the rock volume affected by hydrothermal fluid circulation