What is Carey's source or evidence that "since the Permian [...] the Arctic has been an area of extension"?
I can't cite his specific sources because Carey didn't provide footnotes in his two books. However, his 1976 book includes about 800 references, so I suspect they're listed in there. But I think I can answer the rest of your question.
Carey was apparently the first to suggest that rotation of the Alaskan orocline caused the Arctic to open, and he did so before he converted to expansion. Here's what he wrote in 1976:
"The Alaskan Orocline was described by Carey (1955) and Carey (1958), according to which North America had rotated 28° against Eurasia about a pivot in Central Alaska, thereby opening the Arctic and North Atlantic Oceans. This rotation was confirmed paleomagnetically by Irving (1958). Subsequently, Dr. David Stone went to the Alaskan Geophysical Institute, inter alia to investigate paleomagnetic rotation around the Alaskan Orocline. In due course Packer and Stone (1972) selected nine Jurassic sites along the Aleutian Range - Alaskan Range belt, which they accepted as paleomagnetically stable and mutually consistent, for comparison with the North American block. Their samples did indeed disagree with the American Jurassic pole. But far from showing a sinistral [counter-clockwise] rotation of 28° with respect to the American block, they showed a
dextral [clockwise] rotation of 52°! Surprisingly, this result is precisely should have been predicted from the expanding earth. For, not only the Arctic, but the North Pacific has opened as new crust since the Paleozoic.
"When a segment of a spherical shell is forced to adjust to a sphere of larger radius, radial gores must develop. This is what van Hilten (1963) called "the orange-peel effect." The focal point for the Arctic sphenochasm [FYI: a
sphenochasm is a triangular gap of oceanic crust separating two continental blocks and converging to a point], the North Pacific sphenochasm, and several smaller sphenochasms, is, coincidentally, at Dr Stone's base, the Alaskan Geophysical Institute. Hence, although the Arctic sphenochasm has indeed opened as indicated long ago by me, the Pacific has also opened concurrently. Hence the Alaska and Aleutian ranges (which extend south-west from the pivot into eastern Siberia), should show a large
dextral rotation against North America, which is what Packer and Stone found. [...] The North Pacific sphenochasm heads in the Gulf of Alaska with one near-great-circle arm trending down the cordillerra, and the other down the island arcs of the Aleutians, the Kuriles, Honshu, and the Ryukus." (Carey, 1976, emphasis in original.)
But you don't need to take Carey's word for it when it comes to Arctic tectonics:
"Early ideas on the geology of the northern Alaska continental margin were extrapolated from studies of the surrounding landmasses. Carey (1958) originally suggested that the Beaufort Sea margin of Alaska was created by a rift in which northern Alaska was rotated away from the Canadian Arctic Islands by oroclinal bending about a pivot in the Gulf of Alaska. Regional geologic considerations led Tailleur (l969a, b, and 1973) also to postulate that rotational rifting played a crucial role in the tectonic evolution of the region. Based on data acquired during oil exploration, Rickwood (1970) concurred with the rotational rift hypothesis and proposed that rifting was crucial to creation of the trap that holds the supergiant hydrocarbon deposit at Prudhoe" (Grant, et al, Geology of the Arctic continental margin of Alaska, 1994.)
Here's some recent thinking with respect to timing -- the Arctic began "opening" during the Mesozoic:
"The Arctic Ocean accommodates, besides the vast shelves, the two deep Amerasia and Eurasia basins. It has been inferred that
the former began to develop in the Late Mesozoic, when east Siberia and Alaska, in a not fully understood way, rotated away from Canada, with a rotation pole in the Mackenzie Delta and an inferred transform fault along the former Eurasian margin, today's Lomonosov Ridge. The Eurasia Basin is separated from the Amerasia Basin by the latter, which is a sliver of continental lithosphere that apparently detached from the Eurasian shelf by the opening of the Eurasia basin in early Cenozoic time." (Lorenz, Eurasian Arctic Tectonics, 2005, emphasis added.)
"The present-day scenery of the [East Arctic]
began forming with opening of the Amerasia Ocean (Canada and Podvodnikov–Makarov Basins) in the Late Jurassic–Early Cretaceous and with Cretaceous–Cenozoic rifting related to spreading in the Eurasia Basin. The opening of oceans produced pull-apart and rift basins along continental slopes and shelves of the present-day Arctic fringing seas, which lie on a basement consisting of fragments of the Hyperborean craton and Early Paleozoic to Middle Cretaceous orogens." (Khain, et al., Tectonics and petroleum potential of the East Arctic province, 2009, emphasis added.)
"Sea floor spreading anomalies in the Eurasian Basin (the northern continuation of the mid-Atlantic ridge system) constrain the history of formation of the Arctic Ocean by rifting back to about 55 Ma, but the earlier history of the adjacent Amerasian Basin remains an unsolved plate tectonic puzzle. The wide variety of proposed solutions to this puzzle was chronicled in Lawver et al. [1990]. Since then, increasingly sophisticated geophysical data sets and seismic based geologic relations has lent support to the "rotational opening model", often referred to as the "windshield wiper" model. This model proposes that
Early Cretaceous rifting translated a small continental plate, known as the Arctic Alaska-Chukotka microplate, southward from the Arctic margin of Canada. The plate rotated about a pole located in the McKenzie Delta region, opening the Amerasian Basin by rifting while closing the Angayucham and Anyui ocean basins to the south [e.g. Grantz et al., 1990]. Data in support of this model include correlation of the upper Paleozoic-Mesozoic stratigraphy of the North Slope of Alaska to the Sverdrup Basin of Arctic Canada [Grantz et al., 1990; Embry et al., 1990; Toro et al., 2004], and magnetic and gravity anomalies that identify a paleo-spreading center in part of the Amerasian Basin [Laxon and McAdoo, 1996; Brozena et al., 2002]." (Miller et al., New Insights into Arctic Paleogeography and Tectonics from U-Pb Detrital Zircon Geochronology, 2006, emphasis added.)
So, while Arctic tectonics remains enigmatic, the consensus seems to be that (1) it opened as a sphenochasm (the "rotational opening" or "windshield wiper" model), just as Carey originally proposed in the 50s, and (2) it began opening in the Mesozoic, i.e. after the Permian. And I could find nothing (on line) that indicated that subduction has taken place in the Arctic since that time.
What is Carey's source or evidence that "all of the continents except Antarctica have converged on the Arctic [...] since the Permian"?
Again, I don't know what Carey's specific sources were. But you might want to take a look at "Fragmentation and Assembly of the Continents, Mid-Carboniferous to the Present" (Irving, 1983). (FYI: Nearly all of Irving's references that pre-date Carey's 1976 book are referenced in the latter.) Irving's paper includes maps "showing the motions of the major continental blocks" that were "prepared by first rotating each block into its correct palaeolatitudinal and palaeoazimuthal position for successive time intervals, using the palaeomagnetic poles (palaeopoles). The continents were then assembled into their palaeolongitudinal position using evidence from sea-floor spreading based mainly on the work of Laughton (1975), Norton and Sclater (1980) and Sclater et al. (1977)."
These maps clearly show that "all of the continents except Antarctica have converged on the Arctic [...] since the Permian." But don't take my word for it: check out the two animated GIFs that I've attached, which I created last night from Irving's maps. [See note below about how to view the GIFs.] Needless to say, the continents are shown on a constant-sized earth. (IMO, the South Pole perspective is the best depiction. I slapped the gifs together pretty quickly so they're a bit jumpy.)
[Well, the blog police have converted my GIFs into JPGs, which don't animate. So I put them on a web page: frontier-knowledge.com
slash earth
slash paleomag.html. On Windows, click
CTRL-F5 to rerun; on a Mac, click
Command-R.]
Your turn...