{
 "about": "The record of this Plate: the facts it is drawn from, kept inside the work. Plain JSON; the artwork does not read it. CC0 1.0, no rights reserved.",
 "work": {"title": "Africa", "series": "Plates", "artist": "Kenny Lienhard", "year": 2026, "plate": "2 of 52", "palette": "jasper"},
 "plate": {"name": "Africa", "code": "AF", "model": "PB2002 (Bird 2003)", "class": "major", "area_km2": 58475569, "centroid_lat_lon": [-0.376, 2.747], "ocean_share": 0.5688, "land_share": 0.4312},
 "motion": {"frame": "no-net-rotation", "euler_pole_lat_lon": [49.7782, -74.5558], "rotation_deg_per_million_years": 0.28338, "speed_mm_per_year_at_centroid": 31.21, "heading_deg_at_centroid": 50.5, "speed_range_mm_per_year": [15.9, 31.51], "the_artwork_drifts": "31.21 mm a year along its cut, one frame of rock every 19232 years"},
 "cover": {"deep ocean": 0.4757, "desert": 0.1978, "slope and ridge": 0.0737, "forest": 0.0688, "grassland": 0.0606, "cropland": 0.0588, "rainforest": 0.0384, "shelf sea": 0.0178, "wetland": 0.003, "lakes and rivers": 0.0026, "ocean trench": 0.0015, "towns": 0.0007, "bare rock": 0.0004},
 "palette_from": ["desert", "forest", "deep ocean"],
 "era": {"name": "Green Sahara", "what": "The Sahara green, grass and lakes", "arrives_years_before_2026": [11576, 9076], "leaves_years_before_2026": [6576, 4876], "account": "The past. The Green Sahara: after a first wet spell in the south, grassland, rivers and lakes spread north across the Sahara 11,576 to 9,076 years ago, and Lake Mega-Chad covered about 360,000 square kilometres. The desert came back, north first, 6,576 to 4,876 years ago. Only the desert beds turn to grass, all at once, and only inside those windows.", "source": "Tierney et al. 2017, Science Advances 3:e1601503; Collins et al. 2017, Nature Communications 8:1372; Hely et al. 2014, Climate of the Past 10:681; Armitage et al. 2015, PNAS 112:8543"},
 "history": [{"years_ago": 3565000000, "range_years_ago": [3586000000, 3544000000], "what": "Some of the oldest rocks on this plate formed, in the ancient core of the Zimbabwe craton.", "source": "Horstwood et al. 1999, Geology 27:707, doi:10.1130/0091-7613(1999)027<0707:UPZEFA>2.3.CO;2"}, {"years_ago": 340000000, "range_years_ago": [340000000, 338300000], "what": "Ocean floor still lying under the eastern Mediterranean may date from this time, which would make it the oldest ocean floor in place on Earth. Its age is debated.", "source": "Granot 2016, Nature Geoscience 9:701, doi:10.1038/ngeo2784; Seton et al. 2020, age grid v2020.1 processed here, Geochemistry Geophysics Geosystems, doi:10.1029/2020GC009214"}, {"years_ago": 190000000, "range_years_ago": [194000000, 190000000], "what": "Northwest Africa and North America pulled apart and the Central Atlantic Ocean began to open.", "source": "Labails et al. 2010, Earth and Planetary Science Letters 297:355, doi:10.1016/j.epsl.2010.06.024; Seton et al. 2020, age grid v2020.1 processed here, Geochemistry Geophysics Geosystems, doi:10.1029/2020GC009214"}, {"years_ago": 113000000, "range_years_ago": [140000000, 103000000], "what": "Africa and South America broke apart and the South Atlantic Ocean opened, after a long rift.", "source": "Heine, Zoethout and Muller 2013, Solid Earth 4:215, doi:10.5194/se-4-215-2013"}, {"years_ago": 31000000, "range_years_ago": [31000000, 23800000], "what": "A mantle plume erupted flood lavas, and rifts began to tear Arabia away from Africa.", "source": "Bosworth, Huchon and McClay 2005, Journal of African Earth Sciences 43:334, doi:10.1016/j.jafrearsci.2005.07.020"}, {"years_ago": 5960000, "range_years_ago": [5960000, 5330000], "what": "The Mediterranean was cut off from the Atlantic, and thick salt layers formed as its water evaporated.", "source": "Krijgsman et al. 1999, Nature 400:652, doi:10.1038/23231"}, {"years_ago": 14876, "range_years_ago": [15620, 14132], "what": "The Sahara turned green, covered in plants and dotted with lakes, as the African Humid Period began.", "source": "deMenocal et al. 2000, Quaternary Science Reviews 19:347, doi:10.1016/S0277-3791(99)00081-5"}, {"years_ago": 5576, "range_years_ago": [5855, 5297], "what": "The African Humid Period ended and the Sahara dried out again.", "source": "deMenocal et al. 2000, Quaternary Science Reviews 19:347, doi:10.1016/S0277-3791(99)00081-5"}],
 "outline_lon_lat": [[[-3.45, -52.76], [-2.37, -54.33], [-1.38, -54.05], [-0.44, -54.85], [0.96, -54.83], [3.03, -53.65], [4.41, -54.43], [5.49, -54.54], [6.63, -53.81], [7.77, -54.4], [9.99, -52.79], [10.97, -53.33], [12.9, -51.96], [13.79, -52.48], [15.82, -51.79], [18.54, -52.73], [25.99, -53.58], [26.71, -52.38], [28.11, -52.9], [33.68, -44.56], [37.56, -36.98], [29.66, -31.24], [26.59, -28.19], [26.6, -26.77], [27.91, -26.18], [27.49, -24.4], [29.29, -22.49], [33.11, -21.34], [33.28, -19.68], [35.2, -17.98], [34.85, -14.55], [34.07, -13.17], [34.71, -11.03], [33.56, -8.74], [30.49, -7.48], [28.95, -3.96], [28.87, -2.31], [31.62, 2.48], [30.48, 2.81], [30.47, 4.24], [32.23, 5.72], [36.29, 5.01], [42.03, 11.58], [40.09, 13.21], [40.61, 13.74], [39.67, 15.77], [40.33, 17.27], [38.07, 20.39], [37.54, 22.49], [34.26, 27.89], [36.41, 36.02], [33.74, 34.3], [29.73, 35.43], [27.23, 34.33], [24.59, 34.34], [17.96, 39.17], [17.42, 37.7], [15.83, 37.27], [15.38, 37.34], [15.5, 38.4], [11.12, 39.07], [7.8, 37.36], [-0.75, 35.78], [-2.89, 36.02], [-3.75, 35.6], [-4.06, 34.2], [-5.4, 33.98], [-9.98, 36.65], [-11.59, 35.85], [-13.68, 37.4], [-15.14, 37.02], [-17.58, 37.5], [-23.57, 36.65], [-27.24, 38.78], [-29.91, 39.39], [-31.52, 37.28], [-33.59, 36.74], [-34.75, 35.01], [-36.37, 35.28], [-37.8, 33.5], [-39.4, 33.77], [-42.14, 29.97], [-42.73, 30.07], [-46.2, 24.6], [-46.48, 23.92], [-44.92, 23.65], [-46.77, 15.45], [-45.13, 15.27], [-45.04, 12.68], [-43.88, 12.09], [-43.92, 10.93], [-41.09, 10.79], [-40.14, 8.22], [-38.22, 8.14], [-35.36, 6.61], [-33.62, 6.62], [-32.86, 3.96], [-30.96, 4.06], [-30.74, 1.64], [-30.03, 1.61], [-29.92, 0.8], [-26.47, 1.16], [-26.29, 0.5], [-25.03, 0.61], [-24.61, -1.1], [-16.5, 0.3], [-15.41, -1.49], [-13.16, -0.92], [-12.7, -2.1], [-12.16, -1.95], [-12.14, -4.61], [-11.17, -5.38], [-11.18, -6.76], [-13.62, -7.37], [-13.03, -11.42], [-15.01, -11.89], [-14.48, -14.21], [-13.64, -14.04], [-13.23, -15.66], [-13.24, -16.21], [-14.3, -16.43], [-14.08, -17.99], [-12.96, -17.79], [-11.85, -20.28], [-11.82, -22.15], [-13.83, -22.83], [-13.28, -24.78], [-14.05, -25.74], [-13.27, -28.32], [-12.75, -28.21], [-12.53, -28.94], [-13.99, -29.25], [-13.25, -32.14], [-14.52, -32.4], [-15.1, -35.18], [-17.7, -35.66], [-17.08, -36.47], [-17.53, -37.47], [-16.04, -38.88], [-15.92, -39.68], [-16.87, -40.37], [-15.59, -45.48], [-13.81, -45.8], [-13.33, -47.58], [-10.48, -47.13], [-9.71, -49.22], [-8.14, -48.96], [-7.16, -50.61], [-5.17, -50.22], [-3.45, -52.76]]],
 "sources": ["Plate outlines and motion: Bird, P. (2003). An updated digital model of plate boundaries. Geochemistry, Geophysics, Geosystems 4(3), 1027, doi:10.1029/2001GC000252. No-net-rotation frame computed from PB2002 alone.", "What covers each plate: ESA CCI Land Cover and Water Bodies, NOAA ETOPO 2022, Koppen-Geiger climate maps, NSIDC Sea Ice Index, on a 1 arc-minute grid."],
 "engine_sha256": "a7fbc03acc0fc9ba343881bb88ddaf2b7564564d8bc9cbed16e75e47e01fb3f2"
}