About This Item
- Full TextFull Text(subscription required)
- Pay-Per-View PurchasePay-Per-View
Purchase Options Explain
Share This Item
AAPG Bulletin, V.
Greenhouse shoreline migration: Wilcox deltas
1Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, 78731; [email protected]
2Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, 78731; [email protected]
3Bureau of Economic Geology, Jackson School of Geosciences, University of Texas at Austin, Austin, Texas, 78731; [email protected]
In contrast to the high-frequency and high-amplitude sea level changes of icehouse times, eustatic sea level changes in greenhouse times are now generally accepted as significantly lower frequency and amplitude. As a corollary of this, frequency and extent of cross-shelf shoreline transits in greenhouse times are also likely to have been modest by comparison, and it has been suggested that greenhouse deltas may have been docked at the shelf edge for long periods, thus delivering sediment to deep-water areas more frequently. A revisit of upper Paleocene–lower Eocene Wilcox data across south Texas shows repeated regressive–transgressive shoreline migrations longer than 50 km (31 mi) at a time scale of some 300 k.y. This style of repeated shoreline transits is documented from well logs and is supported by the repeated presence of transgressive estuarine deposits with strong tidal evidence as interpreted from core. We argue, therefore, that Wilcox paleogeography was more varied than commonly portrayed and that the greenhouse shoreline transits were caused by greenhouse sea level change but severely modulated by variable sediment discharge caused by Paleogene hyperthermals. Periodic climate warming during Wilcox deposition and Laramide relief generation in the drainage areas were also responsible for unusually high sediment flux into the Gulf of Mexico. The factor of sediment supply in shoreline growth and retreat has been understated in the literature, partly because of an overemphasis on accommodation as the main driver of stratigraphic sequences.
Pay-Per-View Purchase Options
The article is available through a document delivery service. Explain these Purchase Options.
|Protected Document: $10|
|Internal PDF Document: $14|
|Open PDF Document: $24|
Members of AAPG receive access to the full AAPG Bulletin Archives as part of their membership. For more information, contact the AAPG Membership Department at [email protected].