Skip to Main Content
Book Chapter

Holocene Palynology of the Middle America Trench near Tehuantepec, Mexico

By
Daniel Habib
Daniel Habib
Search for other works by this author on:
David Thurber
David Thurber
Search for other works by this author on:
David Ross
David Ross
Search for other works by this author on:
Jack Donahue
Jack Donahue
Search for other works by this author on:
Published:
January 01, 1970

Pollen profiles of two cores from deep on the seaward flank of the Middle America Trench are used to interpret the Holocene climatic history of adjacent southwestern Mexico. Four broad pollen zones are distinguished, which carbon-14 analysis dates to 8000-9000 yrs B.P.

The total pollen and spores per gram of sediment, together with the abundance and relative percentages of certain pollen types (pine, oak, alder, fir) and altered specimens, are interpreted to reflect variations in moisture and temperature during the Holocene in cordilleran Mexico.

Source vegetation and the proportionate roles of transportation to the sea by streams and winds are considered to be the principal factors in emplacing the pollen zones. Large numbers of specimens per gram sediment, diversity of types, higher percentages of altered grains, and abundance of oak, alder, and fir pollen are presented as evidence for greater available moisture and increased stream activity on the western slopes of the Sierra Madre del Sur. On the other hand, fewer specimens and the preponderance of relatively few types (mostly pine pollen and fern spores) are considered to represent diminished stream activity.

The oldest zone (Zone IV) represents a climatic phase which varied from cool-dry to cool-moist. Zone III is interpreted to reflect the period of maximum warmth and moisture. The next higher zone reflects the driest climatic phase represented in the cores. The upper-most zone (Zone I) marks the return to more moist conditions.

You do not currently have access to this article.

Figures & Tables

Contents

GSA Memoirs

Geological Investigations of the North Pacific

James D. Hays
James D. Hays
Search for other works by this author on:
Geological Society of America
Volume
126
ISBN print:
9780813711263
Publication date:
January 01, 1970

GeoRef

References

Related

Citing Books via

Close Modal
This Feature Is Available To Subscribers Only

Sign In or Create an Account

Close Modal
Close Modal