The subduction of the Copiap
o aseismic ridge, is the causing of the
formation of metallic minerals deposits in north of Chile and
Argentina?
Q4
Mario Gimenez
a, *
, Gemma Acosta
a
, Orlando Alvarez
a
, Agustina Pesce
a
,
Federico Lince Kinger
a
, Andres Folguera
b
a
Instituto Geofísico Sismol ogico Volponi, FCEFN, Universidad Nacional de San Juan, CONICET, Ruta 12 Marquesado (Jardín de Los Poetas), Rivadavia, San
Juan, Argentina
b
IDEAN-CONICET, Universidad de Buenos Aires, Argentina
article info
Article history:
Received 4 March 2019
Accepted 12 April 2019
Available online xxx
Keywords:
Aseismic ridge
Satellite gravity
Ojos del Salado-San Buena Ventura
lineament
Metallic mineral deposits
abstract
The results obtained in this work evince that the metallic mineral deposits located in the northern region
of the Chilean-Pampean flat slab (in northern Chile and north-western Argentina), at approximately 27
30
0
S, would be related to the subduction of the Copiap o aseismic ridge. The analysis of the gravity
anomalies and vertical gravity gradient allows inferring a deflection and truncation of the main trend of
the Andean structures at the extrapolated zone of the Copiap o ridge beneath South America. Thus, the
general NNE-trend of the Andean structures are rotated locally to an ENE-strike within the area of the
Ojos del Salado e San Buena Ventura lineament. We explain that this anomalous behavior of the gravity
derived anomalies is related to the deformational effects imprinted by the ridge subduction. Regions
with a low subduction angle (<30
to horizontal) are related to large mineralization due to fluids released
by dehydration of the subducting crust. In addition, a higher degree of mantle melting could be produced
by a thicker oceanic crust. Therefore, we interpret that the processes associated to the subduction of the
Copiap o aseismic ridge (emplaced on a thickened oceanic crust due to a local compensation of the
seamounts) are the cause of formation and emplacement of big metallic mineral deposits in this region of
Chile and Argentina.
© 2019 Institute of Seismology, China Earthquake Administration, etc. Production and hosting by Elsevier
B.V. on behalf of KeAi Communications Co., Ltd. This is an open access article under the CC BY-NC-ND
license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
1. Introduction Q1
Seamounts, aseismic ridges, hotspot volcanic chains and oceanic
plateaus trajectory reconstructions at the western Pacific, have
been used to explain the development of the Pampean-Chilean flat
subduction zone [1e3].
The ENE-trending Ojos del SaladoeBuena Ventura volcanic
lineament [7] extends at approximately 27
S for almost 300 km
[8,9]. This geologic lineament ranges from the Chilean Central
Valley to the eastern Andean front producing a major transverse
morphological discontinuity through the chain composed of the
highest volcanoes of the world (e.g. the Ojos del Salado dome
complex and Tres Cruces and Incahuasi stratovolcanoes, for more
details see Bonatti et al. [10]; Mpodozis and Kay [11]; Mpodozis
et al. [5]). This lineament is associated with a strong deflection in
the Andean drainage divide area from N in the south to ENE in the
north imposed by aligned stratovolcanoes and dome complexes
that are forming part of the arc front at these latitudes [4] (see
Fig. 1). These centers are affected and controlled by normal and
right lateral structures with regional extent identified in the field
defining a general ENE structural alignment [4e6,12].
The relation between the Copiap o ridge subduction and upper
plate deformation had been previously suggested by different
* Corresponding author.
E-mail address: mgimenez@unsj-cuim.edu.ar (M. Gimenez).
Peer review under responsibility of Institute of Seismology, China Earthquake
Administration.
Production and Hosting by Elsevier on behalf of KeAi
Contents lists available at ScienceDirect
Geodesy and Geodynamics
journal homepage: http://www.keaipublishing.com/geog
https://doi.org/10.1016/j.geog.2019.04.007
1674-9847/© 2019 Institute of Seismology, China Earthquake Administration, etc. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd. This is
an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
Geodesy and Geodynamics xxx (xxxx) xxx
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
GEOG290_proof ■ 12 June 2019 ■ 1/6
Please cite this article as: M. Gimenez et al., The subduction of the Copiap o aseismic ridge, is the causing of the formation of metallic minerals
deposits in north of Chile and Argentina?, Geodesyand Geodynamics, https://doi.org/10.1016/j.geog.2019.04.007