TY - JOUR

T1 - Paleomagnetism of the Mesoproterozoic Gabbro–Dolerite Dykes of the Bunger Hills (East Antarctica)

T2 - A Key Paleomagnetic Pole and Tectonic Implications

AU - Vodovozov, V. Yu

AU - Leitchenkov, G. L.

AU - Egorov, M. S.

AU - Gonzhurov, N. A.

AU - Mikhalsky, E. V.

N1 - Publisher Copyright: © 2021, Pleiades Publishing, Inc.

PY - 2021/3

Y1 - 2021/3

N2 - Abstract: We present paleomagnetic data acquired on 276 samples from 24 Mesoproterozoic (ca 1132 Ma) postkinematic gabbro–dolerite dykes in the Bunger Hills (Queen Mary Land, East Antarctica). In a stereogram, the mean directions of the high-temperature components of natural remanent magnetization from the dyke samples plot in two antipodal clusters; the reversal test is positive. The primary nature of the obtained components is also confirmed by a positive contact test between a dyke and the Paz Cove stock-like metagabbro intrusion (ca 1170 Ma). The obtained paleomagnetic pole (Plat = –21.6° Plong = 268.9° A95 = 5.8° N = 24) coincides with a pole determined earlier for roughly coeval volcanic rocks from Coats Land (ca 1112 Ma) and is quite close to the pole obtained for mafic rocks in the Grunehogna Craton in western Queen Maud Land (ca 1130 Ma). The most probable interpretation of all available paleomagnetic data is the joint movement within a single block of Mawson cratons and the Coats Land block, starting from the turn of 1110 Ma. The opening and closing of the supposed oceanic basins between these blocks at a later time is a much less likely event, it is possible if the paleomagnetic pole and the rotation pole of these blocks coincide. The rigid tectonic connection between the Mawson cratons and the Coates Land from the end of the Mesoproterozoic to the present time contradicts the assumption about the opening and closing of the hypothetical Shackleton paleoocean separating these cratons, and confirms the assumption about the formation of Gondwana as a result of collision processes of the Kuung time (580–520 Ma) during the collision of the paleocontinents Congo–India–Enderby Land and Kalahari–Mawson–Australia. The data obtained make the paleotectonic reconstructions of Rodinia with the participation of East Antarctica more substantiated at the turn of 1110 Ma and at the same time indicate the need to correct the existing models of the collapse of Rodinia and the amalgamation of Gondwana in the Neoproterozoic and Early Paleozoic. The present pole is the third reliable paleomagnetic definition for the Precambrian of East Antarctica.

AB - Abstract: We present paleomagnetic data acquired on 276 samples from 24 Mesoproterozoic (ca 1132 Ma) postkinematic gabbro–dolerite dykes in the Bunger Hills (Queen Mary Land, East Antarctica). In a stereogram, the mean directions of the high-temperature components of natural remanent magnetization from the dyke samples plot in two antipodal clusters; the reversal test is positive. The primary nature of the obtained components is also confirmed by a positive contact test between a dyke and the Paz Cove stock-like metagabbro intrusion (ca 1170 Ma). The obtained paleomagnetic pole (Plat = –21.6° Plong = 268.9° A95 = 5.8° N = 24) coincides with a pole determined earlier for roughly coeval volcanic rocks from Coats Land (ca 1112 Ma) and is quite close to the pole obtained for mafic rocks in the Grunehogna Craton in western Queen Maud Land (ca 1130 Ma). The most probable interpretation of all available paleomagnetic data is the joint movement within a single block of Mawson cratons and the Coats Land block, starting from the turn of 1110 Ma. The opening and closing of the supposed oceanic basins between these blocks at a later time is a much less likely event, it is possible if the paleomagnetic pole and the rotation pole of these blocks coincide. The rigid tectonic connection between the Mawson cratons and the Coates Land from the end of the Mesoproterozoic to the present time contradicts the assumption about the opening and closing of the hypothetical Shackleton paleoocean separating these cratons, and confirms the assumption about the formation of Gondwana as a result of collision processes of the Kuung time (580–520 Ma) during the collision of the paleocontinents Congo–India–Enderby Land and Kalahari–Mawson–Australia. The data obtained make the paleotectonic reconstructions of Rodinia with the participation of East Antarctica more substantiated at the turn of 1110 Ma and at the same time indicate the need to correct the existing models of the collapse of Rodinia and the amalgamation of Gondwana in the Neoproterozoic and Early Paleozoic. The present pole is the third reliable paleomagnetic definition for the Precambrian of East Antarctica.

KW - East Antarctica

KW - gabbro–dolerites

KW - key paleomagnetic pole

KW - mafic dyke swarm

KW - Mawson Craton

KW - paleomagnetism

KW - paleotectonic reconstructions

KW - supercontinent Rodinia

KW - the Mesoproterozoic

KW - COATS LAND

KW - RECONSTRUCTION

KW - CONFIGURATION

KW - BREAK-UP

KW - METAMORPHISM

KW - COLLISION

KW - GEOCHRONOLOGY

KW - gabbro-dolerites

KW - EVOLUTION

KW - GONDWANA

KW - DRONNING MAUD LAND

UR - http://www.scopus.com/inward/record.url?scp=85109354204&partnerID=8YFLogxK

UR - https://www.mendeley.com/catalogue/88ae2d4a-699c-3ccc-8c29-1278b77fd1d1/

U2 - 10.1134/s0016852121020102

DO - 10.1134/s0016852121020102

M3 - Article

AN - SCOPUS:85109354204

VL - 55

SP - 179

EP - 193

JO - Geotectonics

JF - Geotectonics

SN - 0016-8521

IS - 2

ER -