Paleomagnetic Rotations in the Northeastern Caribbean Region Reveal Major Intraplate Deformation Since the Eocene

Abstract

Relative Caribbean‐North American plate motion is partitioned over the trench and intra‐Caribbean plate faults that bound large scale tectonic blocks. Quantifying the kinematic evolution of this tectonic corridor is challenging because much of the region is submarine. We present an extensive regional paleomagnetic dataset (1330 cores from 136 sampling locations) from Eocene and younger rocks of the northern Lesser Antilles, the Virgin Islands, and Puerto Rico, and use a statistical bootstrapping approach to quantify vertical axis block rotations. Our results show that the Puerto Rico–Virgin Island (PRVI) block and the Northern Lesser Antilles (NoLA) block formed two coherently rotating domains that both underwent at least 45° counterclockwise rotation since the Eocene. The first ∼20° occurred in tandem in late Eocene and Oligocene time, after which the blocks were separated in the Miocene by the opening of the Anegada Passage. The last 25° of rotation of the PRVI block ended in the middle Miocene, whereas the NoLA block rotated slower, until the latest Miocene. The boundary between the NoLA block and a non‐rotated Southern Lesser Antilles was likely the Monserrat‐Harvers fault zone. These results require hundreds of kilometers of intra‐Caribbean motions with oroclinal bending of the trench or forearc sliver motion along the curved plate boundary as endmembers. These data invite a critical re‐evaluation of the kinematic reconstruction of Caribbean‐North American plate motion. The consequent changes in paleogeography may provide a new view on the enigmatic eastern Caribbean paleo‐biogeography and the Paleogene dispersal of South American mammals toward the Greater Antilles.This article is protected by copyright. All rights reserved.

Crustal Structure, Deformational History, and Tectonic Origin of the Bahamas Carbonate Platform

“…Recent thermochronologic dating and paleomagnetic data constrain a 45° counterclockwise rotation of the northern Lesser Antilles and Puerto Rico since the Late Eocene (Montheil et al., 2023; Noury et al., 2021). This large rotation is not observed in the southern Lesser Antilles which remained stable during this period.…”

“…Paleomagnetic data used in this study were compiled from Montheil et al. (2023). Seismic reflection data used in this study were compiled from Bangs et al.…”

“…Dated samples of volcanic and granitic rocks used in this study were compiled from Román et al (2021), Hu et al (2022), Rojas-Agramonte et al (2010, Erlich and Pindell (2020), Renne et al (1989), Klitgord et al (1984), andDallmeyer (1984). Paleomagnetic data used in this study were compiled from Montheil et al (2023). Seismic reflection data used in this study were compiled from Bangs et al (2003), Bunce et al (1969), Bowland and Rosencrantz (1988), Boynton et al (1979), Case et al (1990), Diebold et al (1981), Diebold et al (1999), Dillon et al (1972), Erlich and Pindell (2020), Kearey (1974), Ladd et al (1977), Ladd et al (1981), Ladd and Sheridan (1987), Lu and McMillen (1982), Mann et al (1995), Mauffret and Leroy (1997), Massaferro and Eberli (1999), Rodríguez-Zurrunero et al ( 2020), Sheridan et al (1981), Talwani et al (1976), Edgar et al (1971), Triezenberg et al (2016), Uchupi et al (1971), Uchupi (1973), and Watkins et al (1975).…”

“…The formation of the GAC collision can be described in seven phases as shown on the plate reconstructions in Figures 2e–2g: (a) creation of oceanic crust within the proto‐Caribbean seaway formed by the separation of the North and South American plates (Levander et al., 2006; Pindell, 1985; Pindell & Kennan, 2009); (b) Jurassic opening and seafloor spreading in the central GOM and its resulting, counter‐clockwise rotation of the Yucatan block (Lin et al., 2019; Pindell & Dewey, 1982); (c) Cretaceous formation of the Caribbean large igneous province (CLIP) (Pindell & Kennan, 2009; Romito & Mann, 2021); (d) late Cretaceous collision of the Chortis block with island arc terrane north of the CLIP (Pindell, et al., 1988; Rosenfeld, 1993; Sanchez et al., 2016); (e) eastward transport of the CLIP and Caribbean Plate as the western GAC collides and translates past the Bahamas margin and into the Central Atlantic Ocean (Gordon et al., 1997; Mann et al., 1995); (f) large‐scale counter‐clockwise rotation of the eastern GAC collisional zone related to its indentation by the BCP (Erikson et al., 1990; Montheil et al., 2023); and (g) Eocene to recent formation of the Cayman Trough that records the steady, eastward motion of the Caribbean Plate (Rosencrantz et al., 1988) (Figures 2e–2g).…”

“…Following the Triassic‐Jurassic rifting event, the Cretaceous‐Paleogene development of the Bahamas passive margin is recorded by the deposition of the 2–10‐km‐thick BCP (Pindell & Kennan, 2009). The Great Arc of the Caribbean (GAC) diachronously collided with the ramped, southwestern margin of the Bahamas margin from the Paleocene to the early Miocene (Massaferro & Eberli, 1999; Montheil et al., 2023) with the main collision between the Cuban sector of the GAC occurring during the period from the latest Paleocene to early Eocene (Bralower & Iturralde‐Vinent, 1997) (Figure 1a).…”