The Bahia Seamounts: test of a hotspot model and a preliminary South American Late Cretaceous to Tertiary Apparent Polar Wander Path

The origin of Bahia seamounts (Brazil Basin, South Atlantic) in connection to new data on their age

“…The age determined is correlated to the Cretaceous age of limestones occur ring on its slopes; however, it is considerably lower than the age of the oceanic bottom (90-95 Ma) if it is calculated based on the location of linear magnetic anomalies in this region [6]. This contradicts the opin ion described in paper [2] that the submeridional ridge 33° W was formed in the axial part of the MAR. It is apparent that to resolve this contradiction it is required to suggest that right after formation of this ridge the spreading axis shifted eastwards.…”

“…Considering the strike of the submeridional ridge 33° northern latitude, it was most probably formed in the axial zone of the MAR as was suggested in [2]. Formation of the volca nic structures occurred not only in the active zone of the spreading but inside transform fracture zone cross ing it directly northwards of the submeridional ridge of 33° northern latitude.…”

“…Formation of Bahia seamounts is con nected to the hot spot that was localized in the later Cretaceous below the axial part of the Mid Atlantic Ridge (MAR). As the authors of paper [2] believe, the location of the hot spot in this period reflects a subme ridional ridge of 33° western latitude.…”

“…In the western part of the Brazil basin, there is a group of the Bahia sea mounts, composed of several chains mainly of north western strike [1]. There is one reliable age determina tion (62 ± 4 Ma) made with use of isotopic 40 Ar/ 39 Ar of the basalt, composing the southern chain of these sea mounts [2]. The present paper presents new data on the age of the limestones and volcanic rocks obtained during the 28th cruise of the R/V Akademik Vavilov along the northern chain of the Bahia seamounts [3,4] ( Fig.…”

Flexural isostasy and loading sequence of the Dokdo seamounts on the Ulleung Basin in the East Sea (Sea of Japan)

“…ridges, volcanism along fracture zones, and other causes (Watts et al, 1980;Sager and Keating, 1984;Molnar and Stock, 1987;Bryan and Cherkis, 1995;Tarduno and Cottrell, 1997).…”