Association With Mass Extinction
Martma et al.. (2005) assign a Mid-Ludfordian (Upper Ludlow) age to the Burgsvik, which places the beds in close temporal proximity to the Lau event, a late Silurian mass extinction. They also note a positive δ13Corg excursion in the Burgsvik and underlying Eke beds. Such excursions are normally associated with the decrease in oceanic productivity caused by mass extinctions. However, it could also be interpreted as climate, mainly precipitation, controlling the distribution of facies; high δ13C is often observed in deposits formed in arid conditions.
Calner (2005) notes that anachronistic facies are observed in other strata spanning the Lau event, places the Burgsvik beds immediately after this mass extinction (Calner 2005b), noting the occurrence of flat-pebble conglomerates in the underlying Eke beds.
Correlation with the P-S episodes postulated by Jeppsson (1990) suggests that the beds were deposited during a wet period - a P episode.
Read more about this topic: Burgsvik Beds
Famous quotes containing the words association with, association, mass and/or extinction:
“Association with other people corrupts our character Mespecially when we have none.”
—Friedrich Nietzsche (1844–1900)
“It is not merely the likeness which is precious ... but the association and the sense of nearness involved in the thing ... the fact of the very shadow of the person lying there fixed forever! It is the very sanctification of portraits I think—and it is not at all monstrous in me to say ... that I would rather have such a memorial of one I dearly loved, than the noblest Artist’s work ever produced.”
—Elizabeth Barrett Browning (1806–1861)
“The mass of men lead lives of quiet desperation.”
—Henry David Thoreau (1817–1862)
“Man is an over-complicated organism. If he is doomed to extinction he will die out for want of simplicity.”
—Ezra Pound (1885–1972)