Registro de resúmenes

Reunión Anual UGM 2023


SE07-6 Plática invitada

 Resumen número: 0452  |  Resumen aceptado  
Presentación oral

Título:

DIRECT TIMING CONSTRAINTS ON LATE JURASSIC GULF OF MEXICO OPENING AND YUCATAN MARGIN SYN-RIFT MAGMATISM FROM THE CHICXULUB BASEMENT

Autores:

1 Daniel Stockli ← Ponente
University of Texas
stockli@jsg.utexas.edu

2 Sietze de Graaff ED
Vrije Universiteit Brussel
sietze.de.graaff@vub.be

3 Catherine Ross ED
University of Texas
catherine.ross@utexas.edu

4 Lisa Stockli
University of Texas
lstockli@jsg.utexas.edu

5 Sean Gulick
University of Texas
sean@ig.utexas.edu

Sesión:

SE07 Procesos tectónicos y magmáticos mesozoicos durante la ruptura de Pangea ecuatorial occidental Sesión especial

Resumen:

One fundamental puzzle piece in the break-up up equatorial western Pangea is the early Mesozoic opening of the Gulf of Mexico (GOM). However, timing constraints on rifting and magmatic break-up during GOM opening in the Jurassic remain debated and are mainly based on circumstantial evidence from plate kinematic models (~170-160 Ma), Sr isotopic constraints on salt deposition (~169 Ma), and 40Ar/39Ar dating of salt-hosted basaltic xenoliths (~160 Ma). While the eastern GOM has been interpreted as a magma-poor hyperextended margin, geophysical data from central and western GOM documents extensive sub-salt seaward-dipping reflectors (SDRs) and magmatic underplating characteristic of magma-rich rifting and continental break-up. While these SDRs along the southern GOM Yucatán margin are deeply buried in the distal rifted margin and not accessible for study, material from the proximal rifted margin was excavated in the Chicxulub impact structure and drilled by IODP-ICDP Expedition 364. In the impact crater, Carboniferous granitic basement is crosscut by felsic and diabase dikes. In-situ LA-ICP-MS U-Pb dating of apatite from diabase dikes (n=4) yield Jurassic crystallization ages ranging from 169-159 Ma with a weighted mean age of 165 +/- 5 Ma. As such these diabase dikes provide the first direct evidence for Late Jurassic rift magmatism within the proximal rifted Yucatán margin that as had been proposed on the basis of geophysical data. Furthermore, comparison to Chicxulub impact melt implies that dolerite represented volumetrically a major impact target lithology, suggesting voluminous syn-rift magmatism within the proximal Yucatán rifted margin. These new ages for Chicxulub diabase dikes from the Yucatán proximal margin in the southern GOM represent the first in-situ bedrock age constraints on magma-rich continental rifting and break-up in the central GOM, constraining magma-rich GOM break-up as Bathonian-Bajocian and within uncertainty of estimates from Sr salt model ages and salt-hosted basaltic xenoliths.





Reunión Anual UGM 2023
29 de Octubre al 3 de Noviembre
Puerto Vallarta, Jalisco, México