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North Aegean continental lithosphere was thickened by southwest vergent thrusting and continental subduction within the Alpine collisional orogen but has subsequently been greatly extended on a northeast‐southwest axis in the back arc of the Hellenic subduction zone. Crosscutting relationships with two granodiorite bodies emplaced at ∼31–33 Ma, the Xanthi and eastern Vrondou plutons, constrain a pre‐mid‐Oligocene origin of Alpine convergent structures in northeastern Greece. Post‐Alpine thinning of the north Aegean nappe pile began in earliest Miocene time and has been accommodated by a succession of distinct structural systems. The earliest of these, the “Symvolon shear zone”, appears to represent a midcrustal, coaxial rupture of the Falakron marble series, a carbonate platform >5000 m thick that was subducted northeastward beneath high‐grade rocks of the Rhodope metamorphic province in late Alpine time. Zircon and titanite U‐Pb dates and hornblende 40Ar/39Ar dates obtained in this study constrain the intrusion and incipient mylonitization of the Symvolon or “Kavala” granodiorite within the Symvolon shear zone at ∼21–22 Ma. Following its emplacement, the Symvolon body resided at temperatures between 300°C and 500°C for 5–7 m.y., during which coaxial deformation may have continued within a widening Symvolon rupture. The Strymon Valley detachment, a regionally south‐west dipping low‐angle normal fault, succeeded the Symvolon shear zone in middle Miocene time. Southwestward displacement of the Serbo‐Macedonian gneiss complex by as much as 80 km in the hanging wall of this detachment facilitated the unroofing of the Rhodope metamorphic core complex, including the Falakron marble series and several Tertiary plutons, in its footwall. Biotite and K‐feldspar 40Ar/39Ar dates from 11.1 ± 0.2 Ma to 15.5 ± 0.3 Ma yielded by Symvolon granodiorite samples document the cooling of the Rhodope core complex below 150°C–300°C during its southwestward‐progressive exhumation in the footwall of the Strymon Valley detachment.

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The Alaskan Arctic Coastal Plain and its submerged extensions to the north and west, the Beaufort and Chukchi continental shelves, are underlain by a broad, low-relief bedrock surface, the North Beringian Marine Abrasion Platform, which dips gently seaward from the Arctic foothills of the Brooks Range northward to the continental shelf break of the Arctic Basin (Fig. 1). During late Cenozoic time the sea repeatedly transgressed and receded across the North Beringian Platform in response to glacioeustatic sea level fluctuations. A thin veneer of unconsolidated, interfingering marine and nonmarine deposits mantles the bedrock surface and records the succession of geologic environments that have prevailed there during the last 3 m.y. All of these unconsolidated deposits are presently assigned to the Gubik Formation, which has a maximum measured thickness of about 60 m onshore, and thickens to perhaps a few hundred meters in places beneath the Beaufort shelf. In this chapter, we summarize and discuss the depositional history of the Gubik Formation and its bearing on the late Cenozoic geologic and climatic history of the Arctic region. The discussion begins with the onshore exposures, which have been studied in detail over many years, and for which a coherent stratigraphic framework has begun to emerge, and then moves to the offshore deposits, which, though thicker and better preserved, have only recently become the target of stratigraphic investigations. The marine deposits of the Gubik Formation on the Arctic Coastal Plain have intrigued researchers since the early years of this century, when Leffingwell