Hardground, gap and thin black shale: spatial heterogeneity of arrested carbonate sedimentation during the Jenkyns Event (T-OAE) in a Tethyan pelagic Basin (Gerecse Mts, Hungary)

Abstract The Jenkyns Event or Toarcian Oceanic Anoxic was an episode of severe environmental perturbations reflected in carbon isotope and other geochemical anomalies. Although well studied the epicontinental basins NW Europe, its effects are less understood open marine environments. Here we present new (carbon isotope, CaCO 3 , [Mn]) nannofossil biostratigraphic data from Tölgyhát Kisgerecse sections Gerecse Hills (Hungary). These record pelagic carbonate sedimentation near margin Tethys Ocean. A negative excursion c. 6‰ is observed section, a condensed clay black shale layer where content drops association with Event. At Kisgerecse, bio- chemostratigraphic suggest gap lower Toarcian. presence uppermost Pliensbachian hardground, absence lowermost Tenuicostatum ammonite zone at Tölgyhát, together Zone missing anomaly imply arrested sedimentation. calcification crisis sea-level rise led to decrease production terrigenous input, suggesting that volcanogenic CO 2 -driven global warming may have been their common cause.