Large-scale geological structures have controlled the long-term development of the bed and thus the flow of the West Antarctic Ice Sheet (WAIS). However, complete ice cover has obscured the age and exact positions of faults and geological boundaries beneath Thwaites Glacier and Pine Island Glacier, two major WAIS outlets in the Amundsen Sea sector. Here, we characterize the only rock outcrop between these two glaciers, which was exposed by the retreat of slow-flowing coastal ice in the early 2010s to form the new Sif Island. The island comprises granite, zircon U-Pb dated to ~177–174 Ma and characterized by initial ɛNd, 87Sr/86Sr and ɛHf isotope compositions of -2.3, 0.7061 and -1.3, respectively. These characteristics resemble Thurston Island/Antarctic Peninsula crustal block rocks, strongly suggesting that the Sif Island granite belongs to this province and placing the crustal block's boundary with the Marie Byrd Land province under Thwaites Glacier or its eastern shear margin. Low-temperature thermochronological data reveal that the granite underwent rapid cooling following emplacement, rapidly cooled again at ~100–90 Ma and then remained close to the Earth's surface until present. These data help date vertical displacement across the major tectonic structure beneath Pine Island Glacier to the Late Cretaceous.

Mountain building in the Al-Hajar Mountains (NE Oman) occurred during two major shortening stages, related to the convergence between Africa–Arabia and Eurasia, separated by nearly 30 Ma of tectonic quiescence. Most of the shortening was accommodated during the Late Cretaceous, when northward subduction of the Neo-Tethys Ocean was followed by the ophiolites obduction on top of the former Mesozoic margin. This shortening event lasted until the latest Santonian – early Campanian. Maastrichtian to Eocene carbonates unconformably overlie the eroded nappes and seal the Cretaceous foredeep. These neo-autochthonous post-nappe sedimentary rocks were deformed, along with the underlying Cretaceous tectonic pile, during the second shortening event, itself including two main exhumation stages. In this study we combine remotely sensed structural data, seismic interpretation, field-based structural investigations and apatite (U–Th)/He (AHe) cooling ages to obtain new insights into the Cenozoic deformation stage. Seismic interpretation indicates the occurrence of a late Eocene flexural basin, later deformed by an Oligocene thrusting event, during which the post-nappe succession and the underlying Cretaceous nappes of the internal foredeep were uplifted. This stage was followed by folding of the post-nappe succession during the Miocene. AHe data from detrital siliciclastic deposits in the frontal area of the mountain chain provide cooling ages spanning from 17.3 to 42 Ma, consistent with available data for the structural culminations of Oman. Our work points out how renewal of flexural subsidence in the foredeep and uplift of the mountain belt were coeval processes, followed by layer-parallel shortening preceding final fold amplification.

The Omani basement is located spatially distant from the dominantly juvenile Arabian–Nubian Shield (ANS) to its west, and its relationship to the amalgamation of those arc terranes has yet to be properly constrained. The Jebel Ja'alan (NE Oman) basement inlier provides an excellent opportunity to better understand the Neoproterozoic tectonic geography of Oman and its relationship to the ANS. To understand the origin of this basement inlier, we present new radiogenic isotopic data from igneous bodies in Jebel Ja'alan. U–Pb and 40Ar/39Ar geochronological data are used to constrain the timing of magmatism and metamorphism in the jebel. Positive εHf and εNd values indicate a juvenile origin for the igneous lithologies. Phase equilibria modelling is used to constrain the metamorphic conditions recorded by basement. Pressure–temperature (P–T) pseudosections show that basement schists followed a clockwise P–T path, reaching peak metamorphic conditions of c. 650–700°C at 4–7.5 kbar, corresponding to a thermal gradient of c. 90–160°C/kbar. From the calculated thermal gradient, in conjunction with collected trace-element data, we interpret that the Jebel Ja'alan basement formed in an arc environment. Geochronological data indicate that this juvenile arc formed during Tonian time and is older than basement further west in Oman. We argue that the difference in timing is related to westwards arc accretion and migration, which implies that the Omani basement represents its own tectonic domain separate to the ANS and may be the leading edge of the Neoproterozoic accretionary margin of India.

The Wudang Complex located in the central part of South Qinling, has been inferred to be a segment of the Yangtze Craton involved in the orogen. In this study, the cooling/exhumation history of the Wudang Complex is revealed through combined published geochronology data and new apatite fission-track results. Three rapid exhumation episodes related to relevant geodynamic events have been identified. Previous 40Ar–39Ar and (U–Th)/He data indicate that the most significant exhumation, induced by the collision between the North and South China Blocks, occurred from c. 237 to 220 Ma after long-term subsidence and sedimentation of the passive continental margin. The second exhumation event, related to the long-distance effect of the Pacific subduction, occurred during the period from c. 126 to 90 Ma. Following the late Cretaceous – Eocene peneplanation stage, the final late Cenozoic exhumation since c. 15 Ma may be attributed to the combined effect of the eastward growth of the Tibetan Plateau uplift and the Asian monsoon.

The Shackleton Range is a truncated Pan-African Orogen situated at the Weddell Sea margin of East Antarctica. It almost exclusively consists of basement rocks exposed at an elevated, escarpment-bound palaeosurface and is covered locally by patchy remnants of Ordovician, Permian and, controversially, Jurassic terrestrial deposits. This inventory does not match the geological record of any other place in Antarctica. Here we reconstruct the Phanerozoic evolution of the Shackleton Range by means of a multi-disciplinary approach combining petrological, geochemical and geochronological data with thermal history models of zircon and apatite fission track (ZFT, AFT) and (U–Th–Sm)/He (AHe) data. Petrographic, geochemical and 40Ar/39Ar analyses of a sedimentary cover sequence identify volcaniclastic rocks related to the Ferrar/Karoo magmatic event. Thermal history modelling of ZFT ages of 160–215 Ma, AFT ages of 124–225 Ma, AHe ages of 95–169 Ma and kinematic proxies in combination with geological information indicates a complex thermal history comprising at least three cooling episodes interrupted by reheating pulses. Thermal history refers to inversion of part of the Carboniferous–Triassic Transantarctic Basin prior to the 180 Ma Ferrar/Karoo Event and formation of an up to 3.4 km deep extensional Jurassic – Early Cretaceous basin due to Weddell Sea rifting. Basin depth was diminished by regional middle Cretaceous stress field changes. Final basin inversion and surface uplift were likely triggered by far-field tectonics and climatic influence. This history represents a typical example for the transition from an active to passive margin setting along the outer rim of Gondwana.

Thermochronometer data offer a powerful tool for quantifying a wide range of geologic processes, such as the deformation and erosion of mountain ranges, topographic evolution, and hydrocarbon maturation. With increasing interest to quantify a wider range of complicated geologic processes, more sophisticated techniques are needed. This paper is concerned with an inverse problem method for interpreting the thermochronometer data quantitatively. Two novel models are proposed to simulate the crustal thermal fields and paleo mountain topography as a function of tectonic and surface processes. One is a heat transport model that describes the change of temperature of rocks; while the other is surface process model which explains the change of mountain topography. New computational algorithms are presented for solving the inverse problem of the coupled system of these two models. The model successfully provides a new tool for reconstructing the kinematic and the topographic history of mountains.

Analysis of five basement samples from the Vestfold Hills (East Antarctica) reveals pooled apatite fission track (FT) ages ranging from 188 to 264 Ma and mean lengths of 13.7 to 14.9 μm. Quantitative thermal histories derived from these data give consistent results indicating onset of cooling/denudation began sometime prior to 240 Ma, with final cooling below 105°–125°C occurring between 240 and 220 Ma (Triassic). A Cretaceous denudation phase can be inferred from the sedimentary record of the Prydz Bay offshore the Vestfold Hills. The two denudational episodes are likely associated with Palaeozoic large-scale rifting processes that led to the formation of the adjacent Lambert Graben, and to the Cretaceous Gondwana break-up between Antarctica and India. Subsequent evolution of the East Antarctic passive continental margin likely occurred throughout the Cenozoic based on the depositional record in Prydz Bay and constraints (though tentative) from FT data.

The regionally significant 0.5–2 km thick Høybakken detachment in central Norway bounds the southern margin of the Central Norway Basement Window and exhibits a well-developed top-to-the-WSW fabric characteristic of late Scandian, Devonian ductile extension. 40Ar–39Ar data obtained from hornblende, mica and K-feldspar mineral separates of rocks collected in a transect through the Høybakken detachment yield well-defined plateau and isochron mineral ages. Early Devonian exhumation and cooling of the Høybakken detachment footwall is recorded by hornblende ages of ∼ 400 Ma and mica ages of ∼ 390 Ma. The mylonitic fabric overlying the footwall records younger Middle Devonian mica crystallization ages of 384–381 Ma that are among the youngest extensional ductile fabrics dated in the Caledonides and suggest prolonged extensional activity on the Høybakken detachment. After inferred cessation of ductile extension at 381 Ma, the rate of uplift and cooling was reduced, and the footwall records Late Devonian to Early Carboniferous K-feldspar ages of 371–356 Ma. Prolonged extensional activity at Høybakken is compatible with recent U–Pb ages of deformed titanite crystals and established Rb–Sr ages of white mica in shear-related pegmatites, both from the southwestern part of the Fosen Peninsula, and 40Ar–39Ar ages of syn-tectonic mica overgrowth from the adjacent Hitra–Snåsa Fault. Together, these ages suggest the onset of ductile extension soon after ∼ 401 Ma, and with the Middle Devonian crystallization ages determined here, suggest that ductile extension on the Høybakken detachment had a duration of 11–20 Ma. The youngest age of 320 Ma was obtained from a K-feldspar in a cataclastic granite of the Høybakken detachment's hangingwall and is considered to date a phase of post-Scandian brittle deformation that overprinted the mylonitic shear fabric.

This paper reports the dating of apatite fission tracks in eleven rock samples from the South Shetland Archipelago, an island arc located to the north-west of the Antarctic Peninsula. Apatites from Livingston Island were dated as belonging to the Oligocene (25.8 Ma: metasediments, Miers Bluff Formation, Hurd Peninsula) through to the Miocene (18.8 Ma: tonalites, Barnard Point). Those from King George Island were slightly older, belonging to the Early Oligocene (32.5 Ma: granodiorites, Barton Peninsula). Towards the back-arc basin (Bransfield Basin), the apatite appears to be younger. This allows an opening rate of approximately 1.1 km Ma−1 (during the Miocene–Oligocene interval) to be calculated for Bransfield Basin. Optimization of the apatite data suggests cooling to 100 ± 10°C was coeval with the end of the main magmatic event in the South Shetland Arc (Oligocene), and indicates slightly different tectonic-exhumation histories for the different tectonic blocks.