ARAUCARIAN SOURCE OF FOSSILIFEROUS BURMESE AMBER: SPECTROSCOPIC AND ANATOMICAL EVIDENCE

2007·5.5 MB·English

by  George Poinar

ARAUCARIAN SOURCE OF BURMESE AMBER
FOSSILIFEROUS
AND
ANATOMICAL
SPECTROSCOPIC EVIDENCE
George Joseph Lambert
Poinar
Jr. B.
Deportment of Chemistry
Oregon 2145 Road
Sheridan
State University
Corvallis^ Oregon 9733 1 USA. Northwestern University
Evanston, 60208-3
Illinois 13, U.S.A.
1
Wu
Yuyang
Department of Chemistry
Road
21 45 Sheridan
Northwestern
University
Evanston, 60208-3 U.S.A
Illinois
13,
1
ABSTRACT
We
Recent fossil discoveries show that Burmese amber is one of the most significant amber sites from the Early Cretaceous. have used
Bum
both nuclear magnetic resonance (NMR) and anatomical analyses determine the plant source of amber taken from the Noije 2001
to
Summit Site in the Hukawng Valley, Myanmar. All spectra were identified as belonging to Group A, which on the basis of a previous
New
analysis of Zealand amber and copal, is related to members of the Araucariaceae, especially Agathis. Bi- to multiseriate, angular,
wood wood
alternate, contiguous 5-6-sided intertracheal pitting on the fossil is typical of araucarioid pitting and only occurs in of
extinct or extant members of the Araucariaceae. The amber from this mine site is considered to be derived from araucarioid (especialy
Agathis) trees in the Araucariaceae.
Key Words: Burma, fossilized resin, tracheid pits. Nuclear magnetic resonance spectroscopy
RESUMEr'
De recentes decouvertes chez les fossiles montrent que I'ambre birman est Tune des plus importantes sources de Cretace ancien. Nous
(NMR)
avons resonnance magnetique nucleaire analyses anatomiques pour determiner source botanique de
utilise a la fois la et les la
Bum comme
I'ambre trouve a Noije 2001 Summit Site dans la vallee de Hukawng, Myanmar. Tous les spectres ont ete identifies appartenant
membres
au groupe A, qui sur la base d'analyses anterieures sur I'ambre et le copal de Nouvelle-Zelande est lie a des des Araucariacees,
specialement Agathis. Des trous tracheaux a 5-6 cotes, bi- a multiseries, angulaires, alternes, contigus, sur le bols fossile sont typiques
membres
des alveoles des Araucarias ou d'araucarioides et se rencontrent dans le bois des des Araucariaceae. L'ambre de ce site minier
comme
est done considere venant dAgathis, un genre actuel dAraucariaceae."
INTRODUCTION
AD
Burmese amber was traded with China as early as 100, but was not until 1896 that fossils were reported
it
new Hukawng Myanmar
amber was
in these deposits. In 1999, a site discovered in the Valley in (Poinar
et 2005), and palynomorphs from this site were assigned to the Upper Albian of the Early Cretaceous
al.
&
(97-110 million years ago) (Cruickshank Ko 2003). The same deposits have yielded the oldest bee (Poinar
& &
Dancroft 2006), the oldest angiosperm flowers in amber (Poinar Chambers 2005; Poinar 2004) and the
&
evidence of vector borne diseases (Poinar Poinar 2004), making one of the most significant
first fossil
it
Cretaceous amber deposits in the world. Due to the scientific importance of this amber, we have used both
spectroscopic and anatomical analyses determine the plant source.
to
Clues to the determination of source trees of amber deposits can be provided by plant macrofossils or
microfossils found in the amber or in sedimentary beds containing the amber and by spectroscopic analysis
A
of the amber. combination of these methods can then be used to describe source trees, as was done with
&
Agathis levantensis^ the araucarian tree responsible for the production of Middle East amber (Poinar Milki
Up
2001). to the present, the only spectroscopic evidence for the tree source of Burmese amber has been the
&
(NMR)
nuclear magnetic resonance analysis of three samples of Burmese amber (Lambert Poinar 2002).
&
The results of these analyses were conflicting with one sample unassignable (Lambert Erye 1982), one
-
J. Bot. Res. Inst. Texas 1(1): 449 455. 2007
450 Journal of the Botanical Research Institute of Texas 1(1)
related the family Dipterocarpaceae (Lambert 1999a) and the third related the Araucariaceae
to et to
al.
&
Wu,
(Lambert unpublished was undertaken with
research, 2002). Therefore, further analysis additional
Burmese amber samples from new was mined 200L Tracheid one
collected this site that first in fibers in
new
of the amber samples from this site are characterized and used to provide anatomical evidence of the
plant source.
AND METHODS
MATERIALS
The amber samples analyzed in this study were collected from lignitic seams in sandstone-limestone deposits
Bum
Hukawng
Myanmar. The mine was on
in the Valley in located the slope of the Noije about
site hill
SSW
a mile (L5 km) of the old Khanjamaw mine site and southwest of Maingkwan (26°20'N, 96^36'E).
Apparently this had never been mined previously (Chhibber 1934) (Doug Cruickshank, pers. comm.,
site
Bum
December and we 2001 Summit 55
20, 2006), refer to as the "Noije Site.
it
Wood
Fiber Analysis
mm mm
A
square piece of amber measuring approximately 23 on sides and 6 thick contained numerous
all
strips of wood fibers. This piece of amber was cut with a diamond saw along the flat side, leaving two nar-
mm
row pieces of amber, each approximately 3 in thickness. The surfaces of these were polished and the
wood
fibers examined with a Nikon Optiphot optical microscope (with magnifications up to 800x). The
wood
amber amber
pieces containing the fibers are deposited in the Poinar collection (accession# B-P-16)
maintained Oregon
State University.
at
Spectroscopic Studies
Solid-state nuclear magnetic resonance spectroscopy with cross polarization and magic angle spinnin
(CP/MAS) was used amber samples (Lambert Both normal decoupling and
characterize the 1996).
to et
al.
NMR
interrupted decoupling modes were used to examine the solid-state ^^C spectra.
NMR NMR
MHz
Solid state ^^C data were recorded on a 400 Varian System. The Direct Drive console
had a clean rf architecture, a powerful digital receiver, and utilized advanced phase, amplitude modula-
mm
tion. The system had a 5 T3 PENCIL probe. The magic angle spinning rate was set to 5000 Hz. The
cross polarization pulse sequence called tancpx was used normal proton decoupling. For interrupted
for
decoupling, the pulse sequence tancpxidref was used, in which a 50 ps delay was applied in the ^H channel
A
directly before the 180"^ pulse in the ^^C channel. typical parameter set was as follows: spectrum frequency
MHz,
100.544 spectral width 50 kHz, pulse width 3.4 for the 90"" pulse for both ^H and ^^C, delay time
las
number
5 ps, contact time 2 ms, acquisition time 20.5 ms, and scan 256. Spectra were referenced to an
external adamantane peak 5 38.3 and were converted tetramethylsilane 5 Data were collected
at to at 0.0.
and processed with software VnmrJ
IB.
2.
Bum
This procedure was performed on 5 separate samples (Nos. 276, 375, 376, 422, 441) from the Noije
2001 Summit Site. Four of the samples were clear (Nos. 276, 375, 422, 441) and one was opaque (376).
RESULTS
Wood
Fiber Analysis
5-6
The tracheid surfaces contained 2-3 rows (2-3 seriate) of alternately arranged contiguous, angular,
sided tracheid pits (Fig. Most of the bordered tracheid pits were hexagonal with diameters ranging from
1).
11 tol4 pm. None of these biseriate and triseriate pits possessed thickenings, such as crassulae or bars of
Sanio between them. The polygonal pit cavities, which did not extend beyond the pit borders, varied from
round 5-6 some
to sided (Fig. IC). Resin globules occurred within of the tracheids (Fig. IC).
Spectroscopic Analysis
In all samples, the spectra with normal decoupling have the largest peak at 5 38 and a second, smaller peak
at 5 18-20, with a broad grouping in the unsaturated region. With interrupted decoupling, the largest peak
again was at 6 38, with nothing in the unsaturated region. All spectra were identified as belonging to Group
Burmese amber
Poinar et Araucarian source of fossiliferous 451
al.,
=
FiG.1. A. Bi- and tri-seriate tracheid pits on a wood fragment in Burmese amber collected from the Noije Bum 2001 Summit Site. Scale bar 14 jim.
= C
B. Contiguous, alternate, 5-6 sided pits commonly referred to as araucarioid pitting on a wood fragment in Burmese amber. Scale bar 8pm. Pit
=
cavities (arrows) on a tracheid fiber. Note excreted resin globule (arrowhead). Scale bar 15pm.
1 1
452 Journal of the Botanical Research Institute of Texas 1(1)
m
m
rp n u u m u u m m n
'^^^^^
IT \j\ iTi rri xr ^"^ I yj [i ii ir ir \\\ !T ' ii
^ i i i i i [ i i j 1 1 1 1 ; 1 1 1 1 { 1 1 1 1 1 1 j i 'l 1 1 1 1 i i 1 1
I 1 1 j [
200 leo 160 140 120 100 80 60 40 20 ppm
NMR Bum
2. ^^C spectra of Burmese amber sample 376 collected from the Noije 2001 Summit Site with normal decoupling (lower) and interrupted
Fig.
decoupling (upper)(x axis indicates the unit 5 in ppm).
A New
(Fig. 2), which on the basis of a Zealand series reported earher (Lambert et al. 1993), is related to
members commonly known now
of the Araucariaceae, especially Agathis, a genus as kauri pines restricted
Southern Hemisphere.
the
to
DISCUSSION
The arrangement of intertracheary pits and their cavities can be used to characterize familes and genera of
5-6
conifers (Core et 1979; Patel 1968). Bi- to multiseriate, angular, alternate, contiguous, sided longi-
al.
commonly
tudinal tracheid pits as seen on the radial walls of the tracheids, as found here, are referred to
and wood members
as araucarioid pitting only occur in of of the Araucariaceae (Patel 1968; Tidwell 1998).
members
Diameters of tracheid pits in of the Araucariaceae vary from 12 to 16 ]jm (Core et 1979; Tidwall
al.
wood
1998) which within range of the pits in the Burmese amber samples 1-14 The presence of resin
is (1 ijm).
globules or plugs, as found in the fossilized wood, characteristic of araucaroid tracheids (Patel 1968).
is
There are currently three extant genera in the family Araucariaceae: Agathis, Aruacaria and Wollemia.
wood
While the structure oiAgathis and Araucaria similar, (Langenheim 1995), recent resin of these two
is
&
NMR
genera often can be distinguished by analyses (Lambert Poinar 2002), primarily because most Ar-
gum
produce (Lambert from
aucaria species resins 2005). In addition, resin deposits Araucaria trees
et
al.
NMR
are small and do not polymerize and fossilize, as does Agathis (Langenheim 1995). While the spectra
Poinar et Araucarian source of fossiliferous Burmese amber 453
al.,
o(Wollemia and Agathis are similar (Lambert 1999b), there no evidence that Wollemia produces large
et al. is
polymerize and form amber
deposits of resin that deposits.
NMR
Under normal decoupling conditions in analyses, signals are obtained from carbons present in
all
the sample. With interrupted decoupling, signals are selected for quaternary carbons and carbons that are
moving modes
rapidly in the solid while other signals are edited out. These two spectral served as fingerprints
Bum
to analyze and identify the Noije 2001 Summit site amber samples as belonging to the worldwide Group
A, which most similar to members of the genus Agathis in the family Araucariaceae. Determination of this
is
NMR
taxonomic grouping was based on comparisons with previously obtained spectra o( Agathis resin, copal
New
and amber from Zealand (Lambert 1993). has been found, however, that the ^^C fingerprint of
et al. It
gum
modern
resins (as opposed to resins) from the family Araucariaceae are indistinguishable from that of
modern resins from the family Cupressaceae (Lambert 2005). The presence of araucarioid wood fibers
et
al.
NMR
Bum
in the amber from the Noije 2001 Summit collaborative evidence that the spectra reported
site is
member
from
here are a of the Araucariaceae.
A
spectroscopic comparison of resins of the Cupressaceae with those of the Araucariaceae has not
fossil
made members
been since is difficult to obtain samples of fossilized resin associated with present day of
it
the Cupressaceae. There apparently are no localities that contain semi-fossilized or fossilized resin deposits
swamps
of species of the Cupressaceae in soil surrounding the trees, containing the stumps of former forests
New
or in coal deposits, as occurs in Zealand with Agathis (Poinar 1991; Lambert 1993).
et al.
now
While some fragments of amber have been attributed members of the Curpessaceae, (which
to
includes genera of the former family Taxodiaceae), there no evidence that extant Cupressaceae produce
is
copious amounts of resin under normal growth conditions. Members of this family only have a limited capacity
to produce trunk resins (Langenheim 1995), the source of the majority of fossiliferous amber and then only
when
they experience severe traumatic stress. This is in contrast to species oi Agathis, that produce not only
copious amounts of trunk resins, but also were the source of fossilized resins (copal and amber) extending
&
over thousands and millions of years and under wide range of stratigraphic conditions (Halkett Sale
a
&
wood
Lambert While
1986; Poinar 1991; Poinar 2002). of the extinct conifer family Cheirolepidiaceae
may
also contain tracheids with araucaroid radial pitting, the absence of resin ducts and canals a feature
is
& &
wood
typical of these types (Axsmith Jacobs 2005; Taylor Taylor 1993), thus they could not have been
Burmese
the source of amber.
Determining araucarioid (very likely Agathis) trees as the source of Burmese amber congruent with
is
amounts
large of pollen of the araucarian, Araucaricites australis, recovered in a palynological analysis of the
Bum
sedimentary formation that contained the amber the Noije 2001 Summit (Davies 2001).
at Site
Commonly known
as kauri or kauri pines, species o( Agathis can become quite large and long-lived
&
(from 500 to 1000 years) and have been compared with the Giant Sequoias of North America (Halkett Sale
1986). By bulk alone, they would have formed a significant part of the Burmese amber forest. The climate
Burma was which
of tropical- subtropical during the Early Cretaceous (Boucot 2007), the preferred
et al. is
&
now
climate for extant Agathis species, of which are confined to the Southern Hemisphere (Poinar
all
Milki
2001).
Previous spectroscopic analyses of Burmese amber have been conducted with material from other
The sample Burmese amber was provided by Curt Beck and came from Musee
of tested (#7) the
sites. first
National d'Histoire Naturelle, Paris, (No. 101.604). The label stated was collected from Mangotaimaw Hill,
it
&
Myanmar. spectrum was broad and could not be assigned any present group (Lambert Frye 1982).
Its to
In 1992, an analysis was performed on a piece of amber presented to the senior author by a commercial
trading company located in Taiwan. This sample, (#154), which was dark brown, nearly opaque and lacked
Hukong
was coming from Burma. produced spectrum
fossils, represented as the Valley in a typical of
It
the worldwide Group B, which is related to the extant angiosperm family Dipterocarpaceae (Lambert et al.
Bum
1999a; Lambert &r Poinar 2002). In 2002, a sample of Burmese amber (#276) collected from the Noije
2001 Summit Site, where samples were also taken by Cruickshank &r Ko (2003) for their dating studies,
454 Journal of the Botanical Research Institute of Texas 1(1)
showed definite placement in the worldwide Group A, similar the samples presented here. This result
a to
&
Wu,
was simply cited in publications as Lambert unpublished research (2002).
Bum
The present study shows that the amber from the Noije 2001 Summit Site produced from an
is
member
araucarioid, quite probably a of the genus Agathis. If sample #154 did originate from Burma,
it
indicates that least two separate plant families (Araucariaceae and Dipterocarpaceae) were sources of
at
amber Myanmar,
two
in quite possibly distinct geological periods.
at
ACKNOWLEDGMENTS
The authors acknowledge financial support provided by the Graduate Research Institute of Gallaudet Uni-
versity and by the National Science Foundation (Grant No. CHE-03-49412) and thank Roberta Poinar for
comments on earlier drafts of this manuscript and Pierre Jolivet for providing the French abstract. Com-
We
ments of Sherwin Carlquist, Eugene Mazzola, and an anonymous reviewer are greatly appreciated. also
acknowledge an instrument grant from the National Science Foundation (Grant DMR-05-21267).
REFERENCES
AxsMiTH, BJ. and BT. Jacobs. 2005. The conifer Frenelopsis ramosissima (Cheirolepidiaceae) in the Lower Cretaceous
and
of Texas: systematic, biogeographical, paleoecological implications. Plant 66:327-337.
Int. Sci.
J. 1
BoucoT, Xu Chen, and CR. Scotese. 2007. Preliminary compilation of Cambrian through Miocene climatically
A.,
sensitive deposits (submitted).
H.L 1934. The mineral resources of Burma. Macmillan and Company, London.
Chhibber,
Wood
and A.C and
Core, H.A., W.A. Cote, Day. 1979. structure identification. 2'^^ ed. Syracuse University Press,
Syracuse.
and 2003. Geology of an amber the Hukawng northern Myanmar.
Cruickshank, R.D. K. Ko. locality in Valley,
J.
Asian Earth 21:441-455.
Sci.
Davies, E.H. 2001 Palynological analysis and age assignments of two Burmese amber sample sets. Unpublished
.
by Leeward
report Branta Biostratigraphy Ltd. for Capital Corp.
Halkett, and E.V. Sale. 1986. The world of the Kauri. Reed Methuen Ltd, Auckland.
J.
Lambert, and 982. Carbon functionalities amber. Science 21 7:55-57.
J.B. J.S. Frye. in
1
New
and Recent and from Zealand and Aus-
Lambert, J.B., S.C. Johnson, G.O. Poinar, Jr., J.S. Frye. 993. fossil resins
1
Geoarchaeology -1
41 55.
tralia. 8:1
Lambert, Johnson, and G.O. 996. Nuclear magnetic resonance characterization of Cretaceous
S.C. Poinar,
J.B., Jr.
1
amber. Archaeometry 38:325-335.
Lambert, CE. Shawl, S.C. Johnson, and G.O. Poinar, 1999a. Fossil resin from Asia. Ancient Biomolecules
J.B., Jr.
3:29-35.
Lambert, CE. Shaw, G.O. Poinar, and Santiago-Blay. 999b. Classification of modern resins by solid state
J.B., Jr., J.A.,
1
Chem.
nuclear magnetic resonance spectroscopy. Bioorg. 27:409-423.
Lambert, and G.O. Poinar, 2002. Amber: the organic gemstone. Ace. Chem. Res. 35:628-636.
J.B. Jr.
Lambert, Wu, and Santiago-Blay. 2005.Taxonomic and chemical relationships revealed by nuclear mag-
J.B., Y. J.A.
netic resonance spectra of plant exudates. Nat. Prod. 68:635-648.
J.
amber-producing on Hymenaea and
Langenheim, J.H. 995. Biology of trees: focus case studies of Agathis. In: K.B.
1
Anderson and Amber, and American Chemical Washington,
Crelling, eds. Resinite, Resins, Society,
J.C. fossil
DC
1-31.
Pp.
Wood New New
Patel, R.N. 1968. anatomy of Cupressaceae and Araucariaceae indigenous to Zealand. Zealand
J.Bot.6:9-18.
New
Poinar, G.O. 1991. Resinites, with examples from Zealand and Australia. Fuel Process. Technol. 28:
Jr.,
135-148.
and Mim. 2001 Lebanese amber. Oregon
Poinar, G.O. State University Press, Corvallis.
R.
Jr.,
.
Poinar, G.O., Buckley, and A. Brown. 2005. The secrets of Burmese amber. Midi. Amer. Paleont. Soc. 29:
R.
Jr.,
20-29.
Poinar et Araucarian source of fossiliferous Burmese amber 455
al.,
Poinar, Jr., G.O. and R. Poinar. 2004. Paleoleishmania proterus n. gen., n. sp., (Trypanosomatidae: Kinetoplastida)
from Cretaceous Burmese amber. 155:305-310.
Protista
Poinar, G.O. 2004. Programinis burmitis gen. et sp. nov., and R laminatus sp. nov., Early Cretaceous grass-like
Jr.,
monocots Burmese
amber. 7:497-504.
in Austral. Syst. Bot.
1
Poinar G.O. and K.L. Chambers. 2005. Poloeoanthella huangii gen. and sp. nov., an early Cretaceous flower (An-
Jr.,
giospermae) Burmese amber. :2087-2092.
Sida 21
in
Poinar, G.O, and B.N. Danforth. 2006. A fossil bee from Early Cretaceous amber. Science 314:614.
Jr.,
and The and Englewood
Taylor, T.N. E.L.Taylor. 1993. biology evolution of fossil plants. Prentice Hall, Cliffs, NJ.
Common
TiDWELL, W.D. 998. and fossil plants of Western North America, 2^"^ Ed. Smithsonian institution Press.
1