Burmese amber, also known as Burmite or Kachin amber, is amber from the Hukawng Valley in northern Myanmar. The amber is dated to around 100 million years ago, during the latest Albian to earliest Cenomanian ages of the mid-Cretaceous period. The amber is of significant palaeontological interest due to the diversity of flora and fauna contained as inclusions, particularly including insects and arachnids but also birds, lizards, snakes, frogs and fragmentary dinosaur remains. The amber has been known and commercially exploited since the first century AD, and has been known to science since the mid-nineteenth century. Research on the deposit has attracted controversy due to the potential role of the amber trade in funding internal conflict in Myanmar and hazardous working conditions in the mines where it is collected.
Geological context, depositional environment and age
The amber is found in the Hukawng Basin, a large Cretaceous-
Cenozoic sedimentary basin within northern Myanmar. The strata have undergone folding and faulting. The Hukawng basin is part of the larger Myanmar Central Basin, a N-S orientated
Syncline basin extending to the Gulf of Martaban to the south. The basin is considered to be a part of the West Burma block (a.k.a. Burma
terrane), which has a debated tectonic history, it is considered to be associated with the concepts of the Cimmeria and Sibumasu terranes. The block was part of
Gondwana during at least the Early
Paleozoic, but the timing of rifting is very uncertain, with estimates ranging from the
Devonian to Early Cretaceous. It is also disputed whether the block had accreted onto the Asian continental margin by the time of the amber deposition.
Some members of the flora and fauna have Gondwanan affinities,
while others have
Laurasian affinities.
A recent
Paleomagnetism reconstruction finds that the Burma terrane formed an island land mass in the
Tethys Ocean during the Mid Cretaceous at a
latitude around 5-10 degrees south of the equator.
At Noije Bum, located on a ridge, amber is found within fine grained , typically medium to greyish green in colour, resulting from the constituent grains being black, yellow, grey and light green. The fine grained rocks are primarily Grain size sandstone, with beds of silt and shale and laterally persistent thin (1–2 mm thick) coal horizons. Massive Micrite limestone Interbedding of 6-8 centimetre thickness, often containing coalified plant material also occur. This facies association is typically around 1 metre thick and typically thinly bedded and laminated. Associated with the fine grained facies is a set of medium facies primarily consisting of medium to fine grained sandstones also containing thin beds of siltstone, shale and conglomerate, alongside a persistent conglomerate horizon. A specimen of the ammonite Mortoniceras has been found in a sandstone bed 2 metres above the amber horizon, alongside indeterminate gastropods and bivalves.
Paleoenvironment
The Burmese amber paleoforest is considered to have been a tropical rainforest, situated near the coast, where resin was subsequently transported into a shallow marine environment. The shell of a dead juvenile
Puzosia (
Bhimaites) ammonite, four marine
(including
Mathilda) and
Littoral zone isopods entombed in a piece of amber with shell sand,
along with growth of
Isocrinidae ,
and
on the surface of some amber pieces indicate marine conditions for final deposition.
Additionally
Pholadidae (piddock) bivalve
Bioerosion into amber specimens along with at least one pholadid which became trapped was interpreted to show that the resin was still fresh and unhardened when it was being moved into the tidal areas.
However, the phloladids in question, belonging to the extinct genus
Palaeolignopholas, were later interpreted as a freshwater species, and the presence of numerous freshwater insects suggests that the initial environment of deposition was a downstream
Estuary to freshwater section of a river, with the forests extending across coastal rivers, river deltas, lakes, lagoons, and coastal bays.
The forest environment may have been prone to fire, similar to modern tropical peat swamps, based on the presence of fire adapted plants and burned plant remains found in the amber.
The amber itself is primarily disc-shaped and flattened along the Bedding-plane, and is typically reddish brown, with the colour ranging from shades of yellow to red. The opacity of the amber ranges from clear to opaque. Many amber pieces have thin calcite veins that are typically less than , but up to thick. The number and proportion of veins in a piece of amber varies significantly, in some pieces veins are virtually absent, while others are described as being "packed with veinlets".
Fauna and flora
The list of taxa is extraordinarily diverse, with 50 classes (or equivalent), 133 orders (or equivalent), 726 families, 1,757 genera and 2,770 species described as of 2023. The vast majority of the species are arthropods, mostly insects.
Arthropods
Over 2500 species of arthropods (with over 2000 of these species beings insects) are known from the deposit,
notably including the oldest members of the arachnid orders
Palpigradi (
Electrokoenenia)
and
Schizomida and the only known fossil members of
Ricinulei since the Paleozoic.
is a unique
stem-group spider still possessing a tail, with similar forms only known from the Paleozoic,
with over 360 other species of spiders (including the only non Paleozoic fossils of
Mesothelae) being known from Burmese amber, along with over 40 species of scorpions.
Other significant arachnid fossils include some of the oldest
,
as well as the oldest
and
Opilioacaridae mites.
(Coleoptera), reflecting their modern diversity, are represented by over 100 families and over 500 species, with
Hymenoptera (bees, wasps, ants and sawflies) represented by 70 families and 350 species including some of the oldest known
ants.
Fly (Diptera) are represented by over 50 families and over 250 species and true bugs (
Hemiptera) are represented by over 80 families and over 220 species.
Dictyoptera (
cockroaches,
and
, among others), are represented by over 100 species in 28 families.
Odonata (which contains
dragonflies and
damselflies, among other extinct groups), is represented by over 19 families and over 40 species,
far higher than in other Cretaceous amber deposits.
Among the oldest members of the insect order
Zoraptera are known from Burmese amber,
as well as the oldest parasitic
lice and the oldest members of the parasitic insect order
Strepsiptera.
The winged insect
Aristovia is transitional between the extinct "
Notoptera" and modern wingless
Grylloblattidae (ice crawlers).
Over a dozen species each of
Myriapoda (millipedes and centipedes, among others) and
Entognatha (
, among others) have also been reported, along with a number of
woodlice (representing some of the oldest records of the group) and various aquatic crustaceans.
Other invertebrates
A wide variety of other invertebrates have been reported. These include
Gastropoda, including
Freshwater snail and
land snails,
the oldest modern
onychophoran (also known as velvet worms)
Cretoperipatus, as well as
,
Nematomorpha,
and
.
Vertebrates
Only a handful of vertebrates have been described from Burmese amber, these include the
albanerpetontid (a group of extinct salamander-like amphibians)
Yaksha perettii, the frog
Electrorana, a number of primitive toothed birds belonging to the extinct clade
Enantiornithes, including the named species
Elektorornis and
Fortipesavis, the lizards
Protodraco (suggested to be the oldest
agamid)
, Cretaceogekko (suggested to be the oldest modern
gecko)
, Electroscincus (the oldest known
skink)
Barlochersaurus,
(formerly erroneously considered to be a bird),
and the snake
Xiaophis. An indeterminate
theropod dinosaur is known from a tail with preserved feathers.
Flora
A wide variety of plants have been reported from the deposit. These include
flowering plants,
conifers,
ferns,
and
bryophytes.
Other
A number of fungi species have been reported, as well as various microorganisms.
History
The amber is recorded as originating from
Yunnan as early as the first century AD according to the
Book of the Later Han. The trade of Burmese amber into China during the
Han Dynasty has been confirmed by Fourier-transform infrared spectroscopy (FTIR) analysis of amber artifacts from the Eastern Han Dynasty (25 - 220
Common Era).
It was first mentioned in European sources by the Jesuit Priest Álvaro Semedo who visited China in 1613, it was described as being "digged out of mines, and sometimes in great pieces, it is redder than our amber though not so cleane".
[Zherikhin, V.V., Ross, A.J., 2000. A review of the history, geology and age of Burmese amber (Burmite). Bulletin of the Natural History Museum, London (Geology) 56 (1), 3–10.] The locality itself has been known to European explorers since the 1800s with visitation to the Hukawng Valley by Simon Fraser Hannay in 1836–1837.
At that time the principle products of the valley mines were salt, gold, and amber, with the majority of gold and amber being bought by Chinese traders. Hannay visited the amber mines themselves on March 21, 1836, and he noted that the last three miles to the mines were marked with numerous abandoned pits, up to in depth, where amber had been dug in the past. The mining had moved over the hill to a series of 10 pits but no visible amber was seen, suggesting that miners possibly hid the amber found that day before the party arrived. Mining was being performed manually at the time through the use of sharpened
bamboo rods and small wooden shovels. Finer pieces of amber were recovered from the deeper pits, with clear yellow being recovered from depths of The recovered amber was bought with silver or often exchanged for jackets, hats, copper pots, or
opium among other goods. mixed and lower quality amber was sold from around
Thai baht to 4
per seer. Pieces that were considered high quality or fit for use as ornamentation were described as expensive, and price varied depending on the clarity and color of the amber. Women of the valley were noted to wear amber earrings as part of their jewelry.
In 1885 the
Konbaung dynasty was annexed to the
British Raj and a survey of the area was conducted by Dr. Fritz Noetling on behalf of the Geological Survey of India.
The final research before Burmese independence in 1947 was conducted by Dr. H.L. Chhibber in 1934, who provided the most detailed description of Burmite occurrences.
History of research
While a 1892 study considered the amber likely to be
Miocene in age, a study by Theodore Dru Alison Cockerell in 1916 noted archaic nature of the insects, and concluded that the amber must be older, and possibly as old as the Late Cretaceous. Various later authors during the mid-late 20th century suggested either a
Paleocene-
Eocene or an Late Cretaceous age. A Cretaceous age was confirmed during the early 2000s.
While during the 20th century and the first decade of the 21st century research on the deposit was low intensity, during the mid-2010s there was a great increase number of papers published on the deposit, numbering hundreds every year, with a plurality coming from Chinese researchers,
rising from a few dozen species described per year prior to 2014 to over 350 in 2020, though this number had fallen to just over 250 by 2023.
Both the great increase in the amber volume coming out of the mines, as well as a 2013 conference and a 2015 Burmese amber special issue in the journal
Cretaceous Research have been cited as factors in the boom of publications.
Modern exploitation and controversy
Leeward Capital Corp, a small Canadian mining firm, began exporting amber from Myanmar during the 1990s, resulting in the description of a number of fossil species from the deposit.
During the late 2000s, Burmese amber production began to increase as a result of the exhaustion of Chinese amber mines and greater trade between Myanmar and China in general, with the amber trade being initially unaffected by the outbreak of renewed conflict between the Kachin Independence Army, an armed rebel group seeking to scede from Myanmar, and the Burmese armed forces (
Tatmadaw) in 2011. Despite the conflict between them, there was apparently a tacit agreement between the two groups to keep the amber trade flowing, with the KIA controlling the mines, while the Tatmadaw controlled their export to China, with both collecting taxes on the trade.
In 2016, the KIA took full control of the amber mines, and controlled amber export via "various licenses, taxes, restrictions on the movement of labor and enforced auctions".
In June 2017 the
Tatmadaw seized control of the mines from the KIA.
The main amber market in Myanmar is Myitkyina. Most Burmese amber is exported (primarily smuggled) into China, with the primary Chinese market being in Tengchong, Yunnan, with an estimated 100 tonnes of Burmese amber passing into the city in 2015, with a then estimated value between five and seven billion yuan, where it is primarily used for jewelry. Burmese amber was estimated to make up 30% of Tenchong's gemstone market (the rest being Myanmar Jade), and was declared one of the city's eight main industries by the local government.
The working conditions at the mines have been described as extremely unsafe, down deep pits barely wide enough to crawl through, with no accident compensation.
The conclusion that Burmese amber funded the Tatmadaw was disputed by George Poinar and Sieghard Ellenberger, who found that the supply of amber collapsed after the 2017 takeover of the mines by the Tatmadaw, and that most of the current circulation of amber in Chinese markets was extracted prior to 2017.
Other Burmese ambers
Other deposits of amber are known from several regions in Myanmar, with noted deposits in the
Shwebo District of the
Sagaing Region, from the
Pakokku District and
Thayet District districts of
Magway Region and the
Bago District of the
Bago Region.
Tilin amber
A 2018 study on an amber deposit from
Htilin in central Myanmar indicated that deposit to be 27 million years younger than the Hukawng deposit, dating to approximately 72 million years old, placing it in the latest
Campanian age. The deposit was associated with an overlying tuffaceous layer, and underlying nodules of brown sandstone yielded remains of the ammonite
Sphenodiscus. Within a number of arthropod specimens were described though much more poorly preserved than specimens in the Hukawng amber. These include members of
Hymenoptera (
Braconidae,
Diapriidae,
Scelioninae)
Diptera (
Ceratopogonidae,
Chironomidae)
Dictyoptera (
Cockroach,
Mantodea)
,
Berothidae and
bark lice (
Lepidopsocidae) as well as extant ant subfamilies
Dolichoderinae and tentatively
Ponerinae, as well as fragments of
moss.
Hkamti amber
The Hkamti site is located ca. 90 km southwest of the Angbamo site and predominantly consists of limestone, interbedded with mudstone and
tuff, the amber is found in the unconsolidated mudstone/tuff layers. A crinoid was found attached to one amber specimen, alongside marine plant remains in the surrounding sediment, indicating deposition in a shallow marine setting. The amber is generally red-brown, and yellow colouration is rare, the amber is generally found as angular clasts, indicating short transport distance and is more brittle than other northern Myanmar ambers. Zircon dating has constrained the age of the deposit to the early Albian, c. 110 Ma, significantly older than the dates obtained from other deposits. Fauna found in the amber include:
Archaeognatha,
Millipede,
Beetle,
Spider,
Trichoptera,
Neuroptera,
Psocodea,
Isoptera Diptera,
Orthoptera, Pseudoscorpionida,
Hymenoptera and
Thysanoptera.
A lizard,
Retinosaurus, has also been described from the locality.
See also
External links
