Sandwich, Plates, Kenny Lienhard

The Plate in detail

Sandwich, seed 41

Plate 41 of 52 · one of one

Traits

Palette: Obsidian
Structure: Thrust
Event: None
Faults: One
Scale: Standard
Hang: Diagonal
Accent: Repeated
Heading: East-northeast, 75.6°
Speed: 7.29 cm a year

History

The past. At the ice age peak, around 20,000 years ago, winter sea ice spread far north of these islands, to about 48 degrees south, and covered the whole plate each winter, where today it covers about three quarters of it. Ice that lasted through the summer may have reached the plate’s southern edge, but the records disagree on how far. The islands are steep volcanoes, so even with the sea more than 100 metres lower they gained only about 200 square kilometres of land, and their ice caps likely stayed close to today’s extent.

15 million years ago: Back-arc spreading began behind the South Sandwich arc, at least by this time.
10 million years ago: The crust beneath this plate's volcanic arc began to form at the back-arc ridge.

Sources: Lhardy et al. 2021, Climate of the Past 17:1139; Green et al. 2022, Climate of the Past 18:845; Hodgson et al. 2014, Quaternary Science Reviews 100:137; Lambeck et al. 2014, PNAS 111:15296; NSIDC Sea Ice Index v4; ETOPO 2022 · Larter et al. 2003, Geological Society London Special Publications 219:255

Onchain

The file

93,850bytes, the whole work

74,112bytes of code that draws it

3,780bytes of its record, plain text

0network requests

One HTML file, to be etched to Ethereum in full: the code that draws the work (151,144 bytes before compression), this plate’s settings and its record. Nothing is fetched from anywhere else. It reads your clock and slides the view to where the plate is today.

engine sha256 a7fbc03acc0fc9ba343881bb88ddaf2b7564564d8bc9cbed16e75e47e01fb3f2

The record inside it

The plate: Sandwich, a micro plate in Bird’s PB2002 model: 184,414 km², 100% ocean
Its motion: A pole at 38.14°S 33.61°W turning 1.909° per million years; at its centre 7.3 cm a year, heading east-northeast
What covers it: deep ocean 48%, slope and ridge 45%, ocean trench 7%, shelf sea under 1%, and one more
Its past: Its account of the last 30,000 years, with its source
Deep history: Two dated events, the oldest 15 million years ago, each with its source
Its outline: 50 points, to a hundredth of a degree
Licence: CC0 1.0, no rights reserved

Read the record

Sources

The plate, its outline and its motionBird, P. (2003). An updated digital model of plate boundaries. Geochemistry, Geophysics, Geosystems 4(3), 1027.
What covers it, which chose the paletteESA CCI Land Cover and Water Bodies, ETOPO 2022, Köppen-Geiger climate maps, NSIDC Sea Ice Index.

Sandwich

Finished