Summary
A not-yet-peer-reviewed preprint analyses sediment layers in New Jersey and offshore as records of repeated disturbance after the Chicxulub impact. The authors suggest the deposits may capture environmental disruption and recovery over decades.
Sediment layers in New Jersey and offshore may preserve evidence of repeated disturbance in the decades after the Chicxulub impact, according to a preprint that has not been peer reviewed. Its authors compare deposits from several sites and argue that erosion, sediment transport and later settling of impact material produced a more complicated record than a single layer left by the initial event.
The Chicxulub impact is associated with the end-Cretaceous mass extinction. The New Jersey Coastal Plain, about 2,500 kilometres from the crater, offers a record of ejecta fallout and the reshaping of sediments in a different setting. The preprint calls the possible period of disruption and recovery “Earth’s Bad Decades”; it presents that as an interpretation of the deposits, not a settled timeline for the planet as a whole.
Different sites preserve different parts of the aftermath
The deposits vary with location and water depth. At Bass River, the most seaward New Jersey site discussed, a layer of impact spherules appears to record rapid fallout within hours of the impact. At the shallower Ancora site, the spherules have been reworked, in deposits the authors associate with tsunami-related sediment transport.
At Campo Pit and the nearby Buck Pit corehole, the preprint describes a 30–60 centimetre event deposit of red and green clay at sites that were about 20–30 metres deep. It contains reworked impact spherules, an iridium anomaly near the base of the green clay, and thin white kaolinite layers higher up. Grain sizes, deformed sediment and clasts containing reworked spherules lead the authors to interpret this deposit as the result of multiple episodes of erosion, transport and redeposition.
The authors interpret the iridium horizon as fine impact-derived particles that settled a decade or more after the impact. The white layers may record further sediment remobilisation; the preprint raises impact-triggered aftershocks as one possible cause. These are interpretations of the sediment record, rather than direct observations of the events themselves.
At the Inversand core near Edelman Fossil Park, the Main Fossiliferous Layer lies about 50 centimetres above a bioturbated Cretaceous–Paleogene boundary and lacks a significant iridium anomaly. The authors say this points to a complex history of accumulation and reworking at that site, too.
Why the proposed timeline matters
Together, the sites suggest that the aftermath was not recorded as one uniform deposit. Some locations preserve rapid fallout; others show reworked material or evidence of later sediment movement. Offshore sections beneath the continental shelf and slope also contain major gaps in the sediment record, which the authors consider likely to have formed through slope failure and sediment remobilisation triggered by the impact and its aftermath.
The comparison offers a way to investigate how an impact’s effects were preserved in different environments. The authors propose that the New Jersey sections may capture disruption and recovery over decades. Because this interpretation comes from a regional sediment record and the preprint has not been peer reviewed, the “Bad Decades” framing remains a proposed reading of the evidence.