Print this pageAAPG GEO 2010 Middle East
Geoscience Conference & Exhibition
Innovative Geoscience Solutions – Meeting Hydrocarbon Demand in Changing Times
March 7-10, 2010 – Manama, Bahrain
Sea-Level and Paleoproductivity Changes Recorded in Early Paleogene Deposits in Jordan: Events for Regional Correlation
(1) TNO - Geobiology, TNO, Utrecht, Netherlands.
(2) TNO-Oil& Gas, TNO, Utrecht, Netherlands.
The importance of hydrocarbon in the Middle East is well known. However there are still areas where the exploration potential is not fully developed yet, such as in Jordan.
The Paleocene-Eocene depositional record in the Middle East and North Africa is dominated by hemipelagic marls that form important seals for petroleum accumulations in certain areas, and by shallow water limestones which represent good reservoirs, such as the Wafra field between Kuwait and Saudi Arabia.
During the Cretaceous-Paleogene Jordan was located on the stable shelf, in a basin that experienced tectonic instability because of its vicinity to the Syrian Arc, which created expanded hiatus. The early Paleogene depositional record in Jordan is dominated by microfossil-rich hemipelagic marls, which belongs to the Muwaqqar Chalk Formation overlain by the shallow water limestones of the Eocene Umm Rijan Formation. The Muwaqqar Formation is well expanded in the area of Shaubak and Gebel Qurtassyat. The microfossil assemblages indicate outer neritic depositional depth (150-200m) at Gebel Qurtassyat and deeper in Shaubak (upper bathyal: 250-300m). Within the middle Paleocene and at the Paleocene-Eocene interval major paleoenvironmental changes occurred with emphasis on sea level and paleoproductivity fluctuations. Within the middle Paleocene, a peculiar dark-brown shaley-marl bed interrupted the monotonous lithology. This bed rich in organic carbon shows anomalous foraminiferal assemblages, which occur exclusively within this interval and temporarily replacing the normal bathymetrically arranged assemblages. The present data indicate that oxygen deficiency was associated with enhanced productivity. Similarly, a dark-brown shaley interval associated with changing in the microfossil assemblages is also recorded across the Paleocene-Eocene interval, indicating that the Paleocene-Eocene hyperthermal event is also recorded in Jordanian localities. Similar pattern and variation are also described in several localities in Egypt, suggesting that these events occurred on a more regional scale.
This project suggests that variation in the microfossils assemblages, related proxies and sedimentological patterns are successfully used in identify paleobathymetric and paleoproductivity changes and correlating different basins in the whole region, especially in early Paleogene deposits, where their importance is well known in exploration.