The use of apatite fission track thermochronology to constrain fault movements and sedimentary basin evolution in northeastern Brazil

• Published in: Radiation measurements Vol. 39; no. 6; pp. 627 - 633
• Main Authors: da Nóbrega, M.A., Sá, J.M., Bezerra, F.H.R., Hadler Neto, J.C., Iunes, P.J., Guedes, S., Tello Saenz, C.A., Hackspacher, P.C., Lima-Filho, F.P.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Oxford Elsevier Ltd 01.12.2005; Elsevier
• Subjects: Earth sciences; Earth, ocean, space; Exact sciences and technology; Fission track; Geochronology; Geological fault; Isotope geochemistry. Geochronology; Sedimentary basin; Tectonics. Structural geology. Plate tectonics; Thermochronology; Brazil; South Atlantic; Sedimentary basin; Geological fault; Thermochronology; Fission track; South America; sedimentary basins; thermal history; models; ocean opening; Atlantic Ocean; crystalline rocks; reactivation; apatite; fission-track dating; crustal blocks; phosphates; fault displacements; cooling; fault zones; tectonics
• ISSN: 1350-4487; 1879-0925
• DOI: 10.1016/j.radmeas.2004.12.006

An apatite fission track study of crystalline rocks underlying sedimentary basins in northeastern Brazil indicate that crustal blocks that occur on opposite sides of a geological fault experienced different thermal histories. Samples collected on the West block yielded corrected fission-track ages from 140 to 375 Ma, whereas samples collected on the East block yielded ages between 90 and 125 Ma. The thermal models suggest that each block experienced two cooling events separated by a heating event at different times. We concluded that the West block moved downward relative to the East block ca. 140 Ma ago, when sediments eroded from the East side were deposited on the West side. This process represents the early stage of sedimentary basin formation and the opening of the South Atlantic Ocean in the region. Downward and upward movements related to heating and cooling events of these crustal blocks at different periods until recent times are proposed.