Including Original "Paul H. Letters" Copyright © 1996-2024 Paul V. Heinrich / website © 1996-2024 Dirk Ross - All rights reserved.



Wednesday, 26 February 2020

Evidence of Late Quaternary Fires from Charcoal and Siliceous Aggregates, Eastern US 26FEB2020

 Evidence of Late Quaternary Fires from Charcoal and Siliceous Aggregates, Eastern US

It was pointed out to me that Ballard has a 2015 PhD Dissertation

Ballard, J.P., 2015. Evidence of Late Quaternary Fires from Charcoal
and Siliceous Aggregates in Lake Sediments in the Eastern USA.
PhD Dissertation, University of Tenneessee, Knoxville

The abstract in part states:

"A new microscopic charcoal record from Anderson Pond, Tennessee
revealed high fire activity from 23,000–15,000 cal yr BP when
conifers dominated, and during the Mid-Holocene Warm Period
(8000–5200 cal yr BP), when hardwoods dominated. Macroscopic
charcoal analysis of sediments from Pigeon Marsh, Georgia
showed high fire activity from 16,500–14,500 cal yr BP, below
a major hiatus. Jackson Pond, Kentucky and Cahaba Pond, Alabama
had low macroscopic charcoal concentrations during the late
glacial; largest charcoal peaks occurred around 5000 cal yr BP
 at Jackson Pond, and from 1370–640 cal yr BP at Cahaba Pond."

A related paper is:

Marlon, J.R., Bartlein, P.J., Walsh, M.K., Harrison, S.P., Brown, K.J.,
Edwards, M.E., Higuera, P.E., Power, M.J., Anderson, R.S., Briles,
C. and Brunelle, A., 2009. Wildfire responses to abrupt climate
change in North America. Proceedings of the National Academy
of Sciences, 106(8), pp.2519-2524.

The abstract reads in part.

"We also test the hypothesis that a comet impact initiated continental
-scale wildfires at 12.9 ka; the data do not support this idea, nor are
continent-wide fires indicated at any time during deglaciation. There
are, however, clear links between large climate changes and fire
activity. Biomass burning gradually increased from the glacial period
to the beginning of the Younger Dryas. Although there are changes
in biomass burning during the Younger Dryas, there is no systematic
trend. There is a further increase in biomass burning after the
Younger Dryas. Intervals of rapid climate change at 13.9, 13.2, and
11.7 ka are marked by large increases in fire activity. The timing of
changes in fire is not coincident with changes in human population
density or the timing of the extinction of the megafauna."

Yours,

Paul H.

NASA missed these 11 dangerous asteroids, but an AI caught them 26FEB2020

 NASA missed these 11 dangerous asteroids, but an AI caught them

NASA missed these 11 dangerous asteroids, but an AI caught them

The open access paper is:

Hefele, J.D., Bortolussi, F. and Zwart, S.P., 2020. Identifying
Earth-impacting asteroids using an artificial neural network.
Astronomy & Astrophysics, 634, p.A45
.https://www.aanda.org/articles/aa/full_html/2020/02/aa35983-19/aa35983-19.html

Yours,

Paul H.


Monday, 24 February 2020

A lateglacial paleofire record for east-central Michigan (Open Access thesis) - Younger Dryas data 24FEB2020

 A lateglacial paleofire record for east-central Michigan (Open Access thesis) - Younger Dryas data

Below is an open access and interesting and comprehensive study of the

Late Quaternary prehistoric wildfire record for east-central Michigan.


Ballard, J.P., 2009. A lateglacial paleofire record for east-central

Michigan MS thesis, University of Cincinnati, Arts and Sciences.

https://etd.ohiolink.edu/pg_10?0::NO:10:P10_ACCESSION_NUM:ucin1250268463#abstract-files


In part the abstract states:


"The results show contemporaneous fire not only at 12,900 BP but multiple

times between 14,500 and 12,900 BP. This synchronicity of the fires

between 14,500 and 12,900 BP suggests some as-yet-indeterminate large-

scale natural cause, or causes. From 12,900 BP on into the Holocene, the

pattern changes. Fires are continuous with high charcoal peaks at Swift

Lake, continuous at Slack Lake but with slightly lower charcoal peaks

compared to Swift, and having much lower peaks at Lake Sixteen and

Big Fish Lake (charcoal is present but at very low levels)."


Yours,


Paul H.

Friday, 21 February 2020