Early diagenetic alteration of shallow-marine mixed sandstones; an example from the lower Eocene Roda Sandstone Member, Tremp-Graus Basin, Spain

Saved in:
Online Access: Get full text
doi: 10.1016/0037-0738(88)90136-4
Authors:Molenaar, N.; Van de Bilt, G. P.; Van den Hoek Ostende, E. R.; Nio, S. D.
Author Affiliations:Primary:
State Univ. Utrecht, Inst. Earth Sci., Comp. Sedimentol. Div., Utrecht, Netherlands
Volume Title:Sedimentary Geology
Source:Sedimentary Geology, 55(3-4), p.295-318. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0037-0738
Publication Date:1988
Note:In English. 13 refs.; illus. incl. geol. sketch map
Summary:A Lower Eocene shallow-marine sandstone complex, composed of calcareous quartzose arkoses, was modified partly by diagenesis relatively shortly after deposition. The sandstone complex forms the lower member of the Roda formation, which represents part of the Palaeogene fill of the Tremp-Graus basin in the S Pyrenees, Spain. Early diagenesis comprised the introduction of matrix into the sandstone framework through mechanical infiltration and bioturbation, and the precipitation of a mainly aragonitic, rim-cement. This early diagenetic modification occurred in the uppermost parts of sandstone bodies, beneath abandonment surfaces. The early cement stabilized the sandstone framework, and counteracted mechanical compaction. In sandstones lacking this early cement, on the other hand, mechanical compaction severely reduced the primary porosity during a first burial phase, causing the development of a tightly compacted fabric. Mechanical compaction was highly effective because of a high content of ductile grains. Afterwards, two major erosional phases truncated the sandstone complex in the N part of the area studied. Probably through the introduction of meteoric water, unstable carbonate phases, such as aragonite and high-Mg calcite, were replaced by low-Mg calcite, whereas a contemporaneous second calcite cement generation was precipitated. (Authors' abstract) [A.W.H.]
Subjects:Cementation; Cenozoic; Clastic rocks; Compaction; Diagenesis; Early diagenesis; Eocene; Lower Eocene; Materials; Paleogene; Permeability; Porosity; Sandstone; Sedimentary petrology; Sedimentary rocks; Shallow-water environment; Tertiary; Europe; Iberian Peninsula; Pyrenees; Southern Europe; Spain; Roda Sandstone Member; Tremp-Graus Basin
Abstract Numbers:88M/6326
Record ID:1988034973
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from Mineralogical Abstracts, United Kingdom, Twickenham, United Kingdom
Tags: Add Tag
No Tags, Be the first to tag this record!
Be the first to leave a comment!
You must be logged in first