About This Item
Share This Item
Abstract
Chapter from: M
64: Sequence Stratigraphy of Foreland Basin Deposits
Edited By
J.C. Van Wagoner and G.T. BertramAuthors:
Dag Nummedal and C. M. Molenaar Seismic/Sequence Stratigraphy
Published 1995 as
part of Memoir 64
Copyright © 1995 The American Association of Petroleum
Geologists. All Rights Reserved. |
![](images/indent.JPG) |
---|
![](images/indent.JPG) |
---|
![](images/indent.JPG) |
Chapter 9
*
Sequence Stratigraphy
of Ramp-Setting
Strand Plain Successions: The Gallup Sandstone, New Mexico Dag Nummedal
Department of Geology
and Geophysics
Louisiana State University
Baton Rouge, Louisiana,
U.S.A.
C. M. Molenaar*
U.S. Geological Survey
Denver, Colorado, U.S.A.
*
ABSTRACT
The Gallup Sandstone of northwestern New
Mexico is a northeastward-prograding clastic wedge of late Turonian to
earliest Coniacian (Late Cretaceous) age that pinches out about in the
middle of the San Juan basin. Paleoenvironmental and sequence stratigraphic
studies indicate that the Gallup is dominated by strand plain successions
(tongues) that prograded across a gently dipping ramp during repeated episodes
of relative sea level fall. These episodes were superimposed on a long-term
(about 1.2 m.y.) phase of relative sea level rise that controlled the overall
forestepping and aggradational stacking pattern of the tongues. The total
stratigraphic rise of all six Gallup tongues is about 120 m.
The Gallup is divided into chronostratigraphically
significant packages that are bounded by mappable surfaces of erosion and
their downdip conformities. Outcrop studies present incontrovertible evidence,
for at least three of the Gallup tongues, that two concurrent erosional
surfaces formed during sea level falls in this ramp setting. The lower
erosion surface forms a sharp base of the shoreface and is referred to
as a regressive surface of marine erosion. This erosion surface
generally correlates with conformities both updip and downdip. The upper
surface commonly juxtaposes estuarine and fluvial sandstone on truncated
shoreface successions and is referred to as a regressive surface of
subaerial erosion. We consider this upper surface to be the sequence
boundary. The strata between these two erosion surfaces belong to the falling
stage systems tract. The sequence boundary climbs stratigraphic section
(relative to the base of overlying shale) from landward to seaward and
becomes a conformity near the position of the lowstand shoreline.
|
---|
Pay-Per-View Purchase Options
The article is available through a document delivery service. Explain these Purchase Options.
Watermarked PDF Document: $14 |
Watermarked Document A Watermarked Document is branded with the name of the original licensed customer to discourage unauthorized users from sharing the document outside the user's organization. The PDF is no longer restricted to one machine, but can be circulated to others in the same company or department. A Watermarked Document also can be printed for hard copy distribution internally but is not authorized for outside distribution nor posting on the internet. Users will not be able to cut-and-paste text or images from one document to another.
|
Open PDF Document: $24 |
Open Document An Open Document is a fully functional PDF that can be circulated (a digital copy or hard-copy printed documents) outside the purchasing organization. Purchase of an Open Document does NOT constitute license for republication in any form, nor does it allow web posting without prior written permission from AAPG/Datapages ([email protected]).
|
GIS Map Publishing Program