Fracturing in upper Cretaceous Selma group Chalky marls, inner coastal plain of Alabama: stratigraphic (facies) control of joint development and regional joint-strike orientations
Conference
·
· AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States)
OSTI ID:6180839
In the inner coastal plain of Alabama, chalky marl is a distinctive sedimentary facies that contains more original biogenic calcareous-nannofossil components than the adjacent marls. The chalky marl is one facies in the cyclically arranged genetic packages that comprise the Mooreville and Demopolis Chalks of the lower part of the Upper Cretaceous Selma Group. Analysis of genetic-package stratigraphy shows that the chalky marls were deposited during relative sea level highstands. The chalky marls are selectively cemented by calcium carbonate, thus making a relatively well-indurated brittle rock. The chalky marls, in three sections over 15 m thick, host most of the systematic joints in the Mooreville and Demopolis. As a result, fracture-density mapping clearly delineates the outcrop belts of the thick fracture-prone chalky marls. Joint systems in the marls and chalky marls have two main strike trends (N30/degrees/E to N70/degrees/E and N20/degrees/W to N50/degrees/W) and two secondary strike trends (north to N10/degrees/E and east-west), which are nearly parallel and perpendicular, respectively, to crystalline bedrock structural trends and fracture zones. Thus, bedrock structural trends and fracture patterns appear to have propagated through the overlying Mesozoic rocks, dictating the orientation of joints in the chalky marls.
- Research Organization:
- Auburn Univ., AL (USA)
- OSTI ID:
- 6180839
- Report Number(s):
- CONF-8810362-
- Conference Information:
- Journal Name: AAPG (Am. Assoc. Pet. Geol.) Bull.; (United States) Journal Volume: 72:9
- Country of Publication:
- United States
- Language:
- English
Similar Records
Porosity and cementation in upper Cretaceous Mooreville and Demopolis Chalks, central Alabama
Genesis of Upper Cretaceous marl-limestone bedding, Alabama
Overview of sedimentation and sea level change in campanian (Upper Cretaceous) of Northern Margin, Gulf of Mexico
Conference
·
Fri Sep 01 00:00:00 EDT 1989
· AAPG Bulletin (American Association of Petroleum Geologists); (USA)
·
OSTI ID:5141424
Genesis of Upper Cretaceous marl-limestone bedding, Alabama
Conference
·
Sat Sep 01 00:00:00 EDT 1990
· AAPG Bulletin (American Association of Petroleum Geologists); (USA)
·
OSTI ID:5835747
Overview of sedimentation and sea level change in campanian (Upper Cretaceous) of Northern Margin, Gulf of Mexico
Conference
·
Thu Dec 31 23:00:00 EST 1987
·
OSTI ID:6776184