Supplemental Material: Detrital zircon provenance of the Cretaceous–Neogene East Coast Basin reveals changing tectonic conditions and drainage reorganization along the Pacific margin of Zealandia

<div>Table S1: Data sources for composite basement terranes. Table S2: Relative proportions of age fractions for composite basement terranes. Table S3: U-Th-Pb isotopic composition of detrital zircon analyzed at the University of Arizona LaserChron Center. Table S4: U-Th-Pb isotopic composition of detrital zircon analyzed at the University California, Santa Cruz. Table S5: Relative proportions of age fractions for Cenozoic East Coast Basin cover stratigraphy. Table S6: Relative proportions of age fractions for Cretaceous East Coast Basin cover stratigraphy. Table S7: Mixture modeling results for detrital zircon samples. Figure S1: Map of all samples from the basement terrane and cover stratigraphy with detrital zircon U-Pb ages. File S1: Systematic analysis of mixture modeling results. <br></div>

Supplemental Material: Detrital zircon provenance of the Cretaceous–Neogene East Coast Basin reveals changing tectonic conditions and drainage reorganization along the Pacific margin of Zealandia

<div>Table S1: Data sources for composite basement terranes. Table S2: Relative proportions of age fractions for composite basement terranes. Table S3: U-Th-Pb isotopic composition of detrital zircon analyzed at the University of Arizona LaserChron Center. Table S4: U-Th-Pb isotopic composition of detrital zircon analyzed at the University California, Santa Cruz. Table S5: Relative proportions of age fractions for Cenozoic East Coast Basin cover stratigraphy. Table S6: Relative proportions of age fractions for Cretaceous East Coast Basin cover stratigraphy. Table S7: Mixture modeling results for detrital zircon samples. Figure S1: Map of all samples from the basement terrane and cover stratigraphy with detrital zircon U-Pb ages. File S1: Systematic analysis of mixture modeling results. <br></div>

Paleoceanography and dinoflagellate cyst stratigraphy across the Lower–Middle Pleistocene Subseries (Calabrian–Chibanian Stage) boundary at the Chiba composite section, Japan

A dinoflagellate cyst record from the highly resolved Chiba composite section in Japan has been used to reconstruct sea-surface paleoceanographic changes across the Lower–Middle Pleistocene Subseries (Calabrian–Chibanian Stage) boundary at the global stratotype, constituting the first detailed study of this microfossil group from the Pleistocene of the Japanese Pacific margin. Cold, subarctic water masses from 794.2 ka gave way to warming and rapid retreat of the Subpolar Front at 789.3 ka, ~ 2000 years before the end of Marine Isotope Stage (MIS) 20. Throughout the fully interglacial conditions of MIS 19c, assemblages are consistent with warm sea surface temperatures but also reveal instability and latitudinal shifts in the Kuroshio Extension system. The abrupt dominance of Protoceratium reticulatum cysts between 772.9 and 770.4 ka (MIS 19b) registers the influence of cooler, mixed, nutrient-rich waters of the Kuroshio–Oyashio Interfrontal Zone resulting from a southward shift of the Kuroshio Extension. Its onset at 772.9 ka serves as a local ecostratigraphic marker for the Chibanian Stage Global Boundary Stratotype Section and Point (GSSP) which occurs just 1.15 m (= 1300 years) below it. An interval from 770.1 ka to the top of the examined succession at 765.8 ka (MIS 19a) represents warm, presumably stratified but still nutrient-elevated surface waters, indicating a northward shift of the Kuroshio Extension ~ 5 kyrs after the termination of full interglacial conditions on land.

Phanerozoic record of mantle-dominated arc magmatic surges in the Zealandia Cordillera

We integrated new and existing bedrock and detrital zircon dates from the Zealandia Cordillera to explore the tempo of Phanerozoic arc magmatism along the paleo-Pacific margin of southeast Gondwana. We found that episodic magmatism was dominated by two high-magma-addition-rate (MAR) events spaced ~250 m.y. apart in the Devonian (370–368 Ma) and the Early Cretaceous (129–105 Ma). The intervening interval between high-MAR events was characterized by prolonged, low-MAR activity in a geographically stable location for more than 100 m.y. We found that the two high-MAR events in Zealandia have distinct chemistries (S-type for the Devonian and I-type for the Cretaceous) and are unlikely to have been related by a repeating, cyclical process. Like other well-studied arc systems worldwide, the Zealandia Cordillera high-MAR events were associated with upper-plate deformation; however, the magmatic events were triggered by enhanced asthenospheric mantle melting in two distinct arc-tectonic settings—a retreating slab and an advancing slab, respectively. Our results demonstrate that dynamic changes in the subducting slab were primary controls in triggering mantle flare-up events in the Phanerozoic Zealandia Cordillera.

Chapter 2.2a Palmer Land and Graham Land volcanic groups (Antarctic Peninsula): volcanology

The break-up of Gondwana during the Early–Middle Jurassic was associated with flood basalt volcanism in southern Africa and Antarctica (Karoo–Ferrar provinces), and formed one of the most extensive episodes of continental magmatism of the Phanerozoic. Contemporaneous felsic magmatism along the proto-Pacific margin of Gondwana has been referred to as a silicic large igneous province, and is exposed extensively in Patagonian South America, the Antarctic Peninsula and elsewhere in West Antarctica. Jurassic-age silicic volcanism in Patagonia is defined as the Chon Aike province and forms one of the most voluminous silicic provinces globally. The Chon Aike province is predominantly pyroclastic in origin, and is characterized by crystal tuffs and ignimbrite units of rhyolite composition. Silicic volcanic rocks of the once contiguous Antarctic Peninsula form a southward extension of the Chon Aike province and are also dominated by silicic ignimbrite units, with a total thickness exceeding 1 km. The ignimbrites include high-grade rheomorphic ignimbrites, as well as unwelded, lithic-rich ignimbrites. Rhyolite lava flows, air-fall horizons, debris-flow deposits and epiclastic deposits are volumetrically minor, occurring as interbedded units within the ignimbrite succession.