Understanding the Monterey Formation and Similar Biosiliceous Units across Space and Time
CONTAINS OPEN ACCESS

The Monterey Formation is a Miocene marine unit that occurs extensively in the Coast Ranges and in the continental margins of California, and analogous biosiliceous deposits are found around the Pacific Rim and elsewhere in the world. Classic studies on the diatomaceous deposits that characterize the hemipelagic/pelagic facies of the Monterey Formation have been key to understanding the oceanographic and tectonic conditions that lead to the preservation of large volumes of organic-rich hemipelagic biosiliceous sediments, and the properties of these sedimentary deposits once they convert into rocks. This volume presents a collection of recent studies on the Monterey and other similar biosiliceous deposits that offer modern and updated interpretations of this classic unit and its analogues. The volume is dedicated to the memory of Professor Bob Garrison.
Miocene terrestrial paleoclimates inferred from pollen in the Monterey Formation, Naples Coastal Bluffs section, California
*Email: jbarron@usgs.gov
-
Published:September 26, 2022
-
CiteCitation
Linda E. Heusser, John A. Barron*, Gregg H. Blake, Jon Nichols, 2022. "Miocene terrestrial paleoclimates inferred from pollen in the Monterey Formation, Naples Coastal Bluffs section, California", Understanding the Monterey Formation and Similar Biosiliceous Units across Space and Time, Ivano W. Aiello, John A. Barron, A. Christina Ravelo
Download citation file:
- Share
ABSTRACT
We present here a comprehensive record of Miocene terrestrial ecosystems from exposures of the Monterey Formation along the Naples coastal bluffs, west of Santa Barbara, California. Constrained by an updated chronology, pollen analyses of 28 samples deposited between 18 and 6 Ma reflect the demise of mesophytic taxa that grew in a warm, wet environment during the late early and early middle Miocene and the development of a summer-dry/winter-wet Mediterranean climate during the late Miocene. Broadleaf tree pollen from mesophytic woodlands and forests now found in the southeastern United States and China (Liquidambar, Tilia, Ulmus, Carya) characterized the Miocene climatic optimum (16.9–14.7 Ma), the middle Miocene climate transition (14.7–13.8 Ma), and the interval up to ca. 13.0 Ma. Subsequently, during the late middle to early late Miocene, between 13.3 and 9.0 Ma, oak woodlands and herbs (Asteraceae, Amaranthaceae, Poaceae) from beach scrub and chaparral increased as ocean temperatures cooled and the climate became drier. Between ca. 8.9 and 7.6 Ma, pine increased mostly at the expense of oak (Quercus) and herbs, suggesting a period of increasing precipitation. During the latest Miocene (7.5–6.0 Ma), an increase of herb-dominated ecosystems (chaparral, coastal scrub) at the expense of pine reflects the full development of a summer-dry/winter-wet climate in coastal southern California.
- algae
- assemblages
- California
- Cenozoic
- diatoms
- forests
- isotope ratios
- isotopes
- microfossils
- Miocene
- miospores
- Monterey Formation
- Neogene
- O-18/O-16
- oxygen
- paleoclimatology
- paleoenvironment
- palynomorphs
- pollen
- pollen analysis
- Santa Barbara California
- Santa Barbara County California
- stable isotopes
- statistical analysis
- terrestrial environment
- Tertiary
- United States
- Naples California