Reconciling the Cretaceous breakup and demise of the Phoenix

s (Vol. 21, No. 10, pp. 793-813). Elsevier. 1459 Wobbe, F., Gohl, K., Chambord, A., & Sutherland, R. (2012). Structure and breakup history of the 1460 rifted margin of West Antarctica in relation to Cretaceous separation from Zealandia and 1461 Bellingshausen plate motion. Geochemistry, Geophysics, Geosystems, 13(4). 1462 https://doi.org/10.1029/2011GC003742 1463 Wortel, M.J.R. and Spakman, W., 2000. Subduction and slab detachment in the Mediterranean1464 Carpathian region. Science, 290(5498): 1910-1917. 1465 Worthington, T. J., Hekinian, R., Stoffers, P., Kuhn, T., & Hauff, F. (2006). Osbourn Trough: 1466 Structure, geochemistry and implications of a mid-Cretaceous paleospreading ridge in the 1467 South Pacific. Earth and Planetary Science Letters, 245(3-4), 685-701. 1468 Wright, N. M., Seton, M., Williams, S. E., & Mueller, R. D. (2016). The Late Cretaceous to recent 1469 tectonic history of the Pacific Ocean basin. Earth-Science Reviews, 154, 138-173. 1470 https://doi.org/10.1016/j.earscirev.2015.11.015 1471 Yan, C. Y., & Kroenke, L. W. (1993). A plate tectonic reconstruction of the Southwest Pacific, 01472 100 Ma. Oceanic Drilling Program, Scientific Results, 130, 697–709. 1473 Yang, T., Liu, S., Guo, P., Leng, W., & Yang, A. (2020). Yanshanian orogeny during North China's 1474 drifting away from the trench: Implications of numerical models. Tectonics, 39(12), 1475 e2020TC006350. 1476 Zhang, G. L., & Li, C. (2016). Interactions of the Greater Ontong Java mantle plume component 1477 with the Osbourn Trough. Scientific Reports, 6(1), 1-8. 1478 Zhao, X. F., Zhou, M. F., Li, J. W., & Wu, F. Y. (2008). Association of Neoproterozoic A-and I-type 1479 granites in South China: implications for generation of A-type granites in a subduction1480 related environment. Chemical Geology, 257(1-2), 1-15. 1481 1482 This manuscript has been submitted to Earth-Science Reviews


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The southern boundary of the Pacific Plate is the Pacific-Antarctic Ridge (Fig. 1B). This Phoenix Plate's daughters, the Aluk Plate (Herron and Tucholke, 1976), is ongoing below the 166 northern part of the Antarctic Peninsula ( Fig. 1) (e.g. Eagles, 2004). The Aluk Plate is often also 167 referred to as Phoenix Plate, but we prefer the name Aluk Plate to make the distinction with the

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This manuscript has been submitted to Earth-Science Reviews 8 We restore spreading along the different mid-ocean ridges that existed in the southern 235 Panthalassa realm based on published marine magnetic anomaly data of ocean floor presently 236 underlying the south Pacific Ocean (Fig. 4), reviewed in section 4. The ages of the polarity 237 chrons in our reconstruction are updated to the timescale of Ogg (2020). We incorporate all 238 rotation poles as published, even though on short time intervals (<1 Myr) these are likely 239 subject to some noise (Iaffaldano et al., 2012). Our conclusions, however, are not affected by the 240 short time-scale noise and we prefer to see the effect of all interpreted isochrons rather than an 241 arbitrary selection of these.                      Peninsula, the Aluk Plate, is therefore thought to be a descendent of the Phoenix Plate ( Fig. 1; 392 e.g., Barker, 1982;Eagles, 2004). Interestingly, however, for much of the Cenozoic, and until the 393 cessation of spreading around 3.3 Ma, the Aluk Plate has not been spreading relative to the 394 Pacific Plate, but relative to oceanic lithosphere of West Antarctica (Eagles, 2004). Marine

597
We reconstruct the start of spreading in both basins at 120 Ma (Fig. 6B)

689
Rotation poles of the Chasca Plate relative to the Manihiki Plate are calculated in GPlates. In our 690 reconstruction, we ensure that early motion of the Chasca Plate follows the trend of the curved 691 rift structures at the NE Manihiki margin (Fig. 8). In addition, we assume that the Pacific-    Pacific, convergence and subduction continue today (Fig. 1). Conversely, convergence ceased 733 along the southern and western margins in the Late Cretaceous, which was followed by re-

738
It is well agreed upon that a subduction zone was present along the entire East

739
Gondwana margin, from the Antarctic Peninsula to New Caledonia, until 105 Ma (Bradshaw,

768
The Hikurangi-Pacific ridge formed a triple junction with the subduction zone located 769 along the margin of East Gondwana, in the vicinity of the Norfolk Ridge ( Fig. 6 and 7). North of  Plate, for which there is no evidence, and which is two orders of magnitude faster than typical 796 hotspot motions (e.g., Doubrovine et al., 2012). In addition, we tested whether the latest and

818
The first often-cited argument for subduction cessation at 105-100 Ma is the timing of 819 the onset of extension that is recognized in the geology of New Zealand (Bradshaw, 1989;  predicts that this spreading ridge subducted around 100 Ma below New Zealand ( Fig. 7 and 11).

853
The progressive arrival of successively younger oceanic crust before arrival of the spreading 854 ridge may then explain the 128-105 Ma adakitic magmatism, which is often related to the 855 subduction of young oceanic crust (Tulloch and Rabone, 1993).

856
In summary, geological and geochemical interpretations made for New Zealand do not 857 require that subduction ended during c. 105-100 Ma ( Fig. 7 and 11). Alternative structural and 858 stratigraphic arguments for the forearc region of New Zealand (Mazengarb and Harris, 1994; 859 Kamp, 1999Kamp, , 2000

865
Explanations for this cessation have so far mostly focused on regional geological features, such 866 as the arrival of a mid-ocean ridge in the trench (Luyendyk, 1995;Bradshaw, 1989