A new volcanic province: an inventory of subglacial volcanoes in West Antarctica

Maximillian van Wyk de Vries; Robert G. Bingham; Andrew S. Hein

doi:10.1144/SP461.7

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Fig. 1.
(a) Location of the main components of the West Antarctic Rift System and confirmed volcanoes (red circles: after LeMasurier et al. 1990; Smellie & Edwards 2016). (b) Location of Holocene volcanoes (red circles) in the Ethiopia/Kenya branch of the East African Rift (red shaded area). The majority of this activity is aligned along the rift axis with occasional flank volcanism. Data from Siebert & Simkin (2002) and Global Volcanism Program (2013).
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Fig. 2.
Location map of conical edifices (circles) identified from Bedmap2 (greyscale background) across the West Antarctic Rift System. The data are tabulated in Table 2. The circle colour represents the confidence factor used to assess the likelihood of cones being subglacial volcanoes, and the circle size is proportional to the cone's basal diameter. Circles with black rims represent volcanoes that have been confirmed in other studies (LeMasurier et al. 1990; Smellie & Edwards 2016), generally those that have tips which protrude above the ice surface.
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Fig. 3.
The upper panel shows an echogram from NASA's Icebridge mission (NSIDC 2014) that shows generally good agreement between a cone on the echogram and on the Bedmap2 data. The lower panel shows an echogram from Corr & Vaughan (2008) with basal topography picking out two cones; the dark layer above the bed is tephra believed to have erupted around 2000 years ago.
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Fig. 4.
Cross-sections of three cones from this study (numbers 21, 60 and 91: see Fig. 2 and Table 2 for more details and locations) and three prominent shield volcanoes, namely Mauna Kea (Hawaii), Erta Ale and Marsabit (East African Rift).
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Fig. 5.
Volume/height chart of the cones from this study (crosses) superimposed over data from volcanoes worldwide (Grosse et al. 2014). The cones closely fit the morphology data for shield volcanoes, as would be expected for basalt-dominated rift volcanism.

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Table 1.

Classification scheme used in assessing confidence that a cone extracted from Bedmap2 (Fretwell et al. 2013) can be interpreted as a volcano

Confidence assessment criterion	Dataset/source	Confidence score
Confidence assessment criterion	Dataset/source	0	0.5	1
(1) Distance to nearest raw ice-thickness measurement	Figure 3 in Fretwell et al. (2013)	>15 km	5–15 km	<5 km
(2) Expression in ice-surface DEM overlying identified subglacial cone	Bedmap2 ice-surface DEM: Fretwell et al. (2013)	No expression	Associated but off-centre anomaly	Direct overlying anomaly
(3) Expression in MODIS imagery of the ice surface overlying the identified subglacial cone	MODIS Mosaic of Antarctica: Scambos et al. (2007)	No expression	Weak expression	Clear expression
(4) Magnetic anomaly data	ADMAP: Kim et al. (2007)	No anomaly	Weak anomaly	Clear anomaly
(5) Gravity anomaly data	Studinger et al. (2002); Damiani et al. (2014); Scheinert et al. (2016)	No anomaly	Weak anomaly	Clear anomaly

Full scores are given in Table 2.

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Table 2.

Tabulation of subglacial cone coordinates, dimensions and volcanic-interpretation confidence factors (see Table 1)

Number	Height (m)	Average diameter (km)	Elongation ratio	Volume (km³)	Latitude	Longitude	Volcano confidence factor						Previously identified
Number	Height (m)	Average diameter (km)	Elongation ratio	Volume (km³)	Latitude	Longitude	1	2	3	4	5	Sum	Previously identified
1	800	26	1.08	106	−74.00	−80.38	0.5	1	1	0.5	0.5	3.5	Yes
2	600	14	1.15	23	−75.60	−81.60	1	1	0	1	0.5	3.5	No
3	300	7.5	1.14	3	−76.13	−83.53	1	0.5	0	1	0.5	3	No
4	300	18.5	1.18	20	−76.80	−85.27	1	0	0	1	0.5	2.5	No
5	650	24.5	1.04	77	−74.47	−86.40	0.5	0.5	0.5	0.5	0.5	2.5	No
6	350	17.5	1.19	21	−76.74	−87.50	1	0	0.5	1	0.5	3	No
7	250	17	1.27	14	−76.97	−87.89	1	0	0	1	0.5	2.5	No
8	950	29	1.07	157	−77.37	−88.10	1	0	1	0.5	0.5	3	No
9	300	19.5	1.05	22	−77.40	−89.38	1	0.5	1	0.5	0.5	3.5	No
10	350	15.5	1.07	17	−77.32	−90.34	1	0.5	1	0.5	0.5	3.5	No
11	600	32.5	1.17	124	−74.27	−89.58	0.5	0.5	0	0.5	0.5	2	No
12	550	36	1.06	140	−74.07	−91.18	0.5	0	1	0.5	0.5	2.5	No
13	450	27.5	1.20	67	−72.90	−91.30	0	1	0.5	0.5	0.5	2.5	No
14	500	22.5	1.25	50	−74.05	−92.90	1	1	0.5	1	0.5	4	No
15	1400	22.5	1.25	139	−73.73	−93.68	0.5	1	1	1	0.5	4	Yes
16	1450	19.5	1.29	108	−70.03	−125.97	1	1	1	1	0.5	4.5	Yes
17	1300	27	1.25	186	−73.89	−94.64	0.5	1	1	1	0.5	4	Yes
18	400	20	1.11	31	−78.03	−92.95	1	1	0	0.5	0.5	3	No
19	325	18.5	1.18	22	−78.21	−93.20	1	1	0	0.5	0.5	3	No
20	200	9.5	1.11	4	−78.20	−93.82	1	0.5	0	0.5	0.5	2.5	No
21	600	20.5	1.16	49	−78.15	−94.62	1	1	0	0.5	0.5	3	No
22	375	18.5	1.06	25	−78.68	−95.65	1	0	0.5	0.5	0.5	2.5	No
23	250	19	1.11	18	−78.52	−96.16	1	0.5	1	1	0.5	4	No
24	700	26.5	1.30	96	−78.13	−96.36	1	0.5	0	0.5	0.5	2.5	No
25	450	22.5	1.25	45	−78.00	−97.16	1	1	0	0.5	0.5	3	No
26	250	13.5	1.25	9	−78.67	−97.68	1	1	0	1	1	4	No
27	500	24.5	1.13	59	−74.97	−96.54	0.5	1	1	1	0.5	4	No
28	400	16.5	1.36	21	−74.86	−97.42	1	1	0	1	0.5	3.5	No
29	550	16	1.13	28	−75.07	−99.54	1	1	1	1	0.5	4.5	Yes
30	820	20.5	1.16	68	−74.73	−99.04	1	1	1	1	0.5	4.5	Yes
31	650	29	1.15	107	−75.07	−99.54	0.5	1	1	1	0.5	4	Yes
32	750	31	1.07	141	−74.03	−98.83	0.5	0	0	1	0.5	2	No
33	950	26	1.17	126	−74.21	−100.19	1	1	1	0.5	0.5	4	No
34	900	30	1.14	159	−74.51	−99.94	1	0	1	0.5	0.5	3	Yes
35	300	15.5	1.21	14	−74.72	−100.09	1	0	1	0.5	0.5	3	No
36	325	11.5	1.30	8	−75.24	−96.95	1	1	1	0.5	0.5	4	No
37	500	34	1.13	113	−72.19	−97.70	0	1	1	1	0.5	3.5	Yes
38	1025	40.5	1.19	330	−72.54	−97.61	0	0	0.5	1	0.5	2	Yes
39	400	20.5	1.16	33	−72.51	−98.38	0	1	1	1	0.5	3.5	Yes
40	525	28	1.15	81	−72.42	−99.23	0.5	1	1	1	0.5	4	Yes
41	325	20.5	1.16	27	−72.47	−99.94	0	1	1	1	0.5	3.5	Yes
42	550	33.5	1.16	121	−72.32	−101.07	0.5	1	1	0.5	0.5	3.5	Yes
43	225	11.5	1.30	6	−73.87	−103.30	0	0.5	1	1	0.5	3	No
44	675	26.5	1.12	93	−75.45	−103.29	1	1	1	0.5	1	4.5	No
45	350	9.5	1.38	6	−78.41	−101.96	1	0	0	0.5	0.5	2	No
46	575	23	1.19	60	−79.65	−101.80	1	0.5	0	1	0.5	3	No
47	275	12	1.18	8	−80.03	−101.60	1	0.5	0	0.5	0	2	No
48	250	13	1.17	8	−80.15	−101.46	1	0.5	0	0.5	0	2	No
49	175	21.5	1.15	16	−80.17	−103.39	0.5	0.5		0.5	0.5	2	No
50	325	22	1.20	31	−78.87	−102.91	1	0.5	0.5	0.5	0	2.5	No
51	225	27	1.16	32	−80.40	−105.61	0.5	1	0	1	0.5	3	No
52	1175	23	1.19	122	−78.74	−104.24	1	1	1	0.5	1	4.5	No
53	125	15	1.14	6	−77.61	−103.56	1	0.5	0.5	0.5	1	3.5	No
54	225	11.5	1.30	6	−82.05	−111.42	1	0.5	1	1	0.5	4	No
55	175	23	1.19	18	−77.43	−105.77	1	1	1	1	0.5	4.5	No
56	150	9	1.25	2	−77.70	−74.55	1	0.5	0	0.5	0	2	No
57	275	13.5	1.25	10	−78.46	−107.77	1	0.5	1	0.5	0	3	No
58	175	11	1.44	4	−76.72	−106.61	1	1	1	1	0.5	4.5	No
59	150	12.5	1.27	5	−76.87	−106.38	1	1	1	1	1	5	No
60	1200	33.5	1.16	264	−79.15	−111.05	1	0	1	1	1	4	No
61	450	14.5	1.23	19	−79.60	−111.45	1	0	0	1	0.5	2.5	No
62	200	6	1.40	1	−80.42	−114.00	1	0.5	0	1	0	2.5	No
63	425	10	1.22	8	−75.22	−106.92	0	0.5	0.5	0.5	0.5	2	No
64	450	18	1.12	29	−75.71	−108.40	1	0	1	0.5	1	3.5	No
65	375	14.5	1.23	15	−76.11	−107.68	1	0	1	0.5	1	3.5	No
66	400	17	1.27	23	−76.38	−109.78	1	0.5	1	1	1	4.5	No
67	325	10.5	1.33	7	−74.60	−110.62	0.5	1	1	0.5	0.5	3.5	No
68	400	19	1.24	28	−74.81	−110.57	1	1	1	0.5	0.5	4	No
69	350	14	1.33	13	−75.00	−110.43	0.5	1	1	0.5	0.5	3.5	No
70	750	30	1.14	132	−74.89	−111.26	1	1	1	0.5	0.5	4	No
71	2300	51.5	1.15	1197	−75.60	−110.70	1	1	1	0.5	1	4.5	Yes
72	3200	58.5	1.13	2149	−76.52	−112.02	1	1	1	1	1	5	Yes
73	250	15.5	1.07	12	−77.21	−111.92	1	0	0.5	0.5	1	3	No
74	1025	36	1.00	261	−77.72	−112.64	1	0.5	1	1	0.5	4	No
75	300	16	1.13	15	−77.67	−114.04	1	0.5	1	0.5	1	4	No
76	625	26	1.17	83	−77.80	−115.00	1	1	1	0.5	1	4.5	No
77	650	12	1.18	18	−78.08	−115.37	1	0	0.5	0.5	0	2	No
78	400	10.5	1.33	9	−78.11	−115.93	1	1	0.5	0.5	0	3	No
79	350	13.5	1.25	13	−78.93	−115.69	1	0	0.5	1	1	3.5	No
80	325	20.5	1.28	27	−79.68	−113.53	1	1	0	1	1	4	No
81	200	6	1.40	1	−80.38	−115.11	1	0.5	0	1	1	3.5	No
82	125	4.5	1.25	0	−80.38	−115.11	1	0.5	0	1	1	3.5	No
83	150	10	1.22	3	−80.34	−116.40	1	1	0	1	1	4	No
84	1750	31.5	1.10	341	−80.30	−117.49	1	1	1	1	1	5	No
85	800	20	1.22	63	−80.37	−118.90	1	0.5	1	1	1	4.5	No
86	750	18.5	1.31	50	−80.73	−117.56	1	1	1	1	1	5	No
87	150	10.5	1.33	3	−80.81	−118.65	1	1	0	1	1	4	No
88	225	13	1.36	7	−80.87	−120.70	1	0	0	1	1	3	No
89	100	9	1.25	2	−80.27	−117.62	1	1	0	0	0	2	No
90	150	10.5	1.33	3	−80.41	−118.65	1	1	1	1	0.5	4.5	No
91	550	29.5	1.19	94	−80.62	−120.12	1	0.5	1	1	1	4.5	No
92	250	12.5	1.27	8	−79.96	−120.20	1	1	1	1	0.5	4.5	No
93	150	10	1.22	3	−79.24	−119.18	1	1	0	1	0	3	No
94	100	8	1.00	1	−79.37	−119.00	1	1	0	0	0	2	No
95	125	7.5	1.14	1	−79.78	−115.18	1	0	0	0.5	0.5	2	No
96	100	8.5	1.13	1	−78.46	−120.28	1	0	0.5	1	1	3.5	No
97	1000	28.5	1.19	159	−77.54	−118.28	0.5	1	0.5	0.5	0.5	3	No
98	2600	49.5	1.11	1250	−76.96	−117.78	1	1	1	0.5	1	4.5	Yes
99	3850	58	1.11	2542	−76.07	−115.94	0.5	1	1	1	1	4.5	No
100	1350	27.5	1.29	200	−76.73	−125.76	1	1	1	1	0.5	4.5	Yes
101	1100	21	1.21	95	−76.93	−125.73	1	1	1	1	0.5	4.5	Yes
102	1050	20	1.11	82	−77.11	−125.89	0.5	1	1	0.5	0.5	3.5	Yes
103	2400	39	1.17	716	−77.32	−125.97	1	1	1	0.5	0.5	4	Yes
104	1100	22	1.20	104	−77.46	−126.85	0.5	1	1	0.5	0.5	3.5	Yes
105	550	29	1.15	91	−79.24	−128.12	0.5	0	1	0.5	0.5	2.5	No
106	600	17	1.27	34	−81.34	−125.35	1	0.5	0	1	1	3.5	No
107	150	11.5	1.30	4	−82.36	−127.50	1	1	1	1	1	5	No
108	600	25.5	1.13	77	−83.98	−133.02	1	0	1	0.5	0.5	3	No
109	500	39	1.11	149	−84.31	−131.87	1	0.5	1	0.5	0.5	3.5	No
110	125	11.5	1.30	3	−81.82	−128.45	1	0.5	1	1	1	4.5	No
111	100	8	1.29	1	−81.20	−129.58	1	1	0	0	0	2	No
112	550	42	1.15	190	−81.62	−130.38	1	0	1	1	1	4	No
113	275	28.5	1.19	44	−81.87	−130.76	1	0	0	1	1	3	No
114	350	29	1.07	58	−82.41	−134.85	1	1	1	0.5	0.5	4	No
115	150	10.5	1.33	3	−81.10	−132.52	1	0.5	1	1	1	4.5	No
116	400	31.5	1.25	78	−81.36	−133.60	1	1	1	0	0.5	3.5	No
117	100	6	1.40	1	−81.64	−134.55	1	0	0	0	1	2	No
118	250	15.5	1.07	12	−81.55	−135.48	1	0	1	1	0.5	3.5	No
119	550	21.5	1.15	50	−80.35	−131.14	1	1	1	0	1	4	No
120	250	11.5	1.30	6	−80.50	−134.03	1	0	1	1	1	4	No
121	950	36	1.12	242	−80.23	−134.29	1	0.5	1	1	0	3.5	No
122	250	30.5	1.03	46	−79.57	−132.88	1	0	0	0.5	0.5	2	No
123	325	23.5	1.24	35	−80.40	−136.32	0.5	0	1	1	1	3.5	No
124	400	29	1.00	66	−80.08	−138.89	0.5	0.5	0	1	0.5	2.5	No
125	275	32.5	1.10	57	−79.39	−137.82	0.5	0.5	1	1	0.5	3.5	No
126	125	17.5	1.19	8	−79.67	−138.15	0.5	0	1	0.5	0.5	2.5	No
127	250	19	1.11	18	−79.76	−139.69	1	0	0	0.5	0.5	2	No
128	400	24	1.18	45	−78.70	−137.18	0.5	1	0	0.5	0.5	2.5	No
129	300	10.5	1.33	6	−78.61	−137.87	0.5	0	1	0.5	0.5	2.5	No
130	600	25.5	1.13	77	−78.39	−139.25	1	0.5	1	1	0.5	4	No
131	425	39.5	1.08	130	−79.00	−142.10	1	0.5	0	0.5	0.5	2.5	No
132	700	31	1.00	132	−78.15	−140.91	1	0.5	1	0.5	0.5	3.5	No
133	675	22	1.00	64	−77.91	−140.89	1	1	1	0.5	0.5	4	No
134	2600	52.5	1.06	1406	−73.71	−126.54	0	1	1	1	0.5	3.5	Yes
135	400	28	1.15	62	−74.69	−127.78	0.5	1	1	0.5	0.5	3.5	No
136	200	4.5	1.25	1	−75.98	−128.21	0	1	1	1	0.5	3.5	Yes
137	1700	47.5	1.16	753	−76.11	−128.64	0	1	1	1	0.5	3.5	No
138	325	16	1.13	16	−75.80	−128.57	0	1	1	1	0.5	3.5	No
139	1500	19.5	1.17	112	−75.98	−129.11	0	1	1	1	0.5	3.5	Yes
140	450	5.5	1.20	3	−75.90	−129.29	0	1	1	1	0.5	3.5	No
141	1800	36	1.06	458	−75.98	−132.31	0.5	1	1	0.5	0.5	3.5	Yes
142	900	21	1.00	78	−76.24	−132.63	0.5	1	1	0.5	0.5	3.5	Yes
143	400	5	1.00	2	−76.22	−133.14	0	1	1	0.5	0.5	3	No
144	600	13	1.17	20	−76.27	−135.11	0	1	1	0.5	0.5	3	Yes
145	950	18.5	1.18	64	−76.27	−136.12	0	1	1	0.5	0.5	3	Yes
146	800	9.5	1.11	14	−75.88	−137.95	0	1	1	0.5	0.5	3	No
147	275	19.5	1.17	21	−75.62	−138.08	0	1	1	0.5	0.5	3	No
148	600	8.5	1.13	9	−78.09	−153.87	1	1	1	1	0.5	4.5	No
149	450	21.5	1.15	41	−78.13	−155.26	1	1	1	1	0.5	4.5	No
150	775	23	1.19	80	−77.88	−153.60	1	1	1	1	0.5	4.5	No
151	275	16.5	1.06	15	−77.89	−154.81	1	1	1	1	0.5	4.5	No
152	100	7	1.33	1	−78.19	−157.00	0	1	1	0.5	0.5	3	No
153	125	18	1.25	8	−82.11	−154.71	0	0	1	0.5	0.5	2	No
154	100	16.5	1.06	5	−81.96	−157.64	0	0	1	0.5	0.5	2	No
155	150	24	1.18	17	−81.53	−163.39	1	1	1	0.5	0.5	4	No
156	225	15	1.00	10	−78.00	−165.52	0	0.5	0.5	1	0.5	2.5	No
157	100	12	1.18	3	−77.18	−164.77	0	0.5	0.5	1	0.5	2.5	No
158	1400	34	1.13	318	−85.96	−163.98	0.5	1	1	0.5	0.5	3.5	Yes
159	400	10.5	1.33	9	−78.39	167.56	0.5	1	1	1	0.5	4	Yes
160	325	16.5	1.20	17	−78.50	166.04	0	1	1	1	0.5	3.5	Yes
161	1600	29	1.07	264	−78.61	165.08	0	1	1	1	0.5	3.5	Yes
162	2050	39.5	1.14	628	−78.73	163.67	0	1	1	1	0.5	3.5	Yes
163	2250	33	1.13	481	−77.78	168.67	0	1	1	1	0.5	3.5	Yes
164	1800	29.5	1.19	307	−77.70	166.83	0	1	1	1	0.5	3.5	Yes
165	1250	21	1.10	108	−77.49	166.78	0	1	1	1	0.5	3.5	Yes
166	425	22.5	1.14	42	−77.23	167.68	0	1	1	1	0.5	3.5	Yes
167	350	20.5	1.16	29	−77.18	166.94	0	1	1	0.5	0.5	3	Yes
168	750	16.5	1.20	40	−74.58	164.22	1	1	1	1	0.5	4.5	Yes
169	600	26.5	1.21	83	−73.80	169.69	0.5	1	1	1	0.5	4	Yes
170	950	33.5	1.09	209	−73.42	164.70	0	1	1	1	0.5	3.5	Yes
171	1550	34.5	1.16	362	−72.78	169.89	0	1	1	0.5	0.5	3	Yes
172	750	17.5	1.19	45	−71.93	170.41	0	1	1	1	0.5	3.5	Yes
173	500	25.5	1.13	64	−76.45	−165.16	0	0.5	0.5	0.5	0.5	2	No
174	450	34.5	1.09	105	−76.37	−166.16	0	0.5	0.5	0.5	0.5	2	No
175	450	13.5	1.25	16	−76.12	−72.41	0.5	1	1	1	0.5	4	Yes
176	400	9.5	1.38	7	−73.68	−78.91	0	1	1	0.5	0.5	3	No
177	550	20	1.22	43	−73.70	−79.43	0.5	1	1	1	0.5	4	Yes
178	300	17	1.27	17	−74.67	−78.72	0.5	1	1	1	0.5	4	Yes
Average	621	21.3	1.18	121	−77.56	−120.28	0.69	0.69	0.71	0.74	0.57	3.40

The final column identifies whether the cone was a previously recognized volcano (Yes) or a new discovery (No). Most of the previously identified volcanoes are catalogued in LeMasurier et al. (1990).

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Table 3.

Statistical comparison of the morphologies of the cones identified in this study identified as volcanoes

	Height (m)		Average diameter (km)		Axis ratio		Volume (km³)		Confidence factor
	(a)	(b)	(a)	(b)	(a)	(b)	(a)	(b)	(a)
Average	701	940	21.9	17.1	1.19	2.11	144	150	3.75
Standard Deviation	641	670	10.7	11.6	0.09	0.81	345	371	0.56
Median	475	810	20.5	15.3	1.17	1.98	42	31	3.5
Minimum	100	100	4.5	2.3	1.00	1.13	0.5	0.2	3
Maximum	3850	3030	58.5	63.3	1.44	5.23	2542	3086	5

Comparison with: (a) those from a global database of shield volcanoes; and (b) Grosse et al. (2014). The two are similar, apart from the long-short axis ratio; our cones are, on average, more circular than shield volcanoes elsewhere. This could be linked to specific glaciovolcanic eruption mechanisms, but is most likely a data bias due to our detection methods excluding more elliptical edifices.