Geofísica

The Ediacaran-Cambrian transition is marked by the diversification of metazoans in the marine realm. However, this is not recorded by the Ediacaran-Cambrian Bambuí Group of the São Francisco basin, Brazil. Containing the sedimentary record of a partially confined foreland basin system, the Bambuí strata bear rare metazoan remnants and a major carbon isotope positive excursion decoupled from the global record.

The end-Triassic mass extinction is one of the Phanerozoic’s five largest mass extinctions. The extinction is usually attributed to climate change associated with degassing of erupting basalt from the Central Atlantic Magmatic Province (CAMP). However, recent work has shown that the earliest known CAMP basaltic flows occur stratigraphically above the extinction horizon indicating that the relationship between the CAMP and the extinction is more complex when resolved at higher temporal resolution.

Lithospheric stresses in intraplate regions are characterized by many different wavelengths. In some areas, stresses vary over short distances of less than ~100 km, but in other regions uniform stresses can be recognized for more than ~1000 km or so. However, not all intraplate regions are well sampled with stress measurements to allow a good characterization of the lithospheric stresses. On January 3, 2017, a magnitude 4 mb earthquake occurred near the equatorial coast of the Maranhão, an aseismic area of northern Brazil.