Burmese amber

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Wing of the dragonfly Burmalindenia in a cabochon of Burmese amber, showing typical red colouration of the amber. Scale bar = 5mm

Burmese amber, also known as Burmite or Kachin amber, is

internal conflict in Myanmar
and hazardous working conditions in the mines where it is collected.

Geological context, depositional environment and age

Geological context of Burmese amber in northern Myanmar

The amber is found within the Hukawng Basin, a large Cretaceous-

Laurasian affinities.[3] A recent paleomagnetic 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.[4]

At Noije Bum, located on a ridge, amber is found within fine grained

ammonite Mortoniceras has been found in a sandstone bed 2 metres above the amber horizon, alongside indeterminate gastropods and bivalves.[5] Lead-uranium dating of zircon crystals of volcanic clasts within the amber bearing horizons has given a maximum age of 98.79 ± 0.62  million years ago (Ma), making the deposit earliest Cenomanian in age.[6] Unpublished data by Wang Bo on other layers suggests an age range of deposition of at least 5 million years.[7] The amber does not appear to have undergone significant transport since hardening or be redeposited. The strata at the site are younging upwards, striking north north-east and dipping 50-70 degrees E and SE north of the ridge and striking between south south-east and south-east and dipping 35-60 degrees south-west south of the ridge, suggesting the site is on the northwest limb of a syncline plunging to the northeast. A minor fault with a conspicuous gouge zone was noted as present, though it appeared to have no significant displacement.[5] Several other localities are known, including the colonial Khanjamaw and the more recent Inzutzut, Angbamo, and Xipiugong sites, within the vicinity of Tanai. The Hkamti site SW of the Hukawng basin has been determined to be significantly older, dating to the early Albian around ca. 110 Ma and is therefore considered distinct.[8]

Paleoenvironment

A Puzosia (Bhimaites) species juvenile shell in Burmese amber

The Burmese amber paleoforest is considered to have been a

isopods entombed in a piece of amber with shell sand,[9] along with growth of Isocrinid crinoids, corals and oysters on the surface of some amber pieces indicate marine conditions for final deposition.[10] Additionally pholadid (piddock) bivalve borings 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.[11] 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 estuarine to freshwater section of a river, with the forests extending across coastal rivers, river deltas, lakes, lagoons, and coastal bays.[12] 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.[13]

The amber itself is primarily disc-shaped and flattened along the

coniferous origin, with a likely araucarian source tree, based on spectroscopic analysis and wood fragment inclusions,[14] though a pine origin has also been suggested.[15]

Fauna and flora

Main article: Paleobiota of Burmese amber

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.[16]

Arthropods

Further information: Insect paleobiota of Burmese amber
Fossil of the tailed stem-group spider Chimerarachne in Burmese amber

Over 2500 species of arthropods (with over 2000 of these species beings insects) are known from the deposit,

woodlice (representing some of the oldest records of the group) and various aquatic crustaceans.[16]

Other invertebrates

A wide variety of other invertebrates have been reported. These include

onychophoran (also known as velvet worms) Cretoperipatus,[27] as well as nematodes, nematomorphs, annelids and flatworms.[16]

Vertebrates

Fossil of the frog Electrorana in Burmese amber

Only a handful of vertebrates have been described from Burmese amber, these include the

theropod dinosaur is known from a tail with preserved feathers.[32]

Flora

A wide variety of plants have been reported from the deposit. These include

bryophytes.[16]

Other

A number of fungi species have been reported, as well as various microorganisms.[16]

History

The amber is apparently referred to in ancient Chinese sources as originating from

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".[34] 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.[35][36] 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 15 ft (4.6 m) 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 40 ft (12 m) 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 1/ ticals to 4 rupees 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.[35] 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.[34] 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.[34]

History of research

While a 1892 study considered the amber likely to be

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.[34] 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,[37] 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.[16]

Modern exploitation and controversy

See also:
Internal conflict in Myanmar
Miners digging and sorting Burmese amber at Noije Bum in the Hukawng Valley, undated photograph

Leeward Capital Corp, a small Canadian mining firm, controlled the deposit from the mid-1990s to c. 2000, though the history of exploitation during the 2000s is obscure. The Kachin Independence Army (KIA), an armed rebel group seeking to secede Kachin province from Myanmar, controlled the area during the early to mid 2010's. During the early 2010s, production rapidly increased. The working conditions at the mines have been described as extremely unsafe, down 100 m (330 ft) deep pits barely wide enough to crawl through, with no accident compensation.[7] The KIA controlled amber export via numerous licenses, taxes, restrictions on movement of labor, and enforced auctions.[38] The main amber market in Myanmar is Myitkyina. Most amber is smuggled into China, primarily for jewelry, with estimates of around 100 tonnes passing through to the main market of Tengchong, Yunnan in 2015, with a then estimated value between five and seven billion yuan. 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.[39] The presence of calcite veins are a major factor in determining the gem quality of pieces, with pieces with a large number of veins having significantly lower value.[5] In June 2017 the Tatmadaw seized control of the mines from the KIA.[40]

Sales of amber were alleged to help fund the Kachin conflict by various news organisations in 2019.[41][42] Interest in this discussion rose in March 2020 after the highly publicised description of Oculudentavis, which made the cover of Nature.[43] On April 21, 2020, the Society of Vertebrate Paleontology (SVP) published a letter of recommendation to journal editors asking for “a moratorium on publication for any fossil specimens purchased from sources in Myanmar after June 2017 when the Myanmar military began its campaign to seize control of the amber mining”.[44] On April 23, 2020 Acta Palaeontologica Polonica stated that it would not accept papers on Burmese amber material collected from 2017 onwards, after the Burmese military took control of the deposit, requiring "certification or other demonstrable evidence, that they were acquired before the date both legally and ethically".[45] On May 13, 2020, the Journal of Systematic Palaeontology published an editorial stating that it would no longer consider papers based whole or in part on Burmese amber material, regardless of whether in historic collections or not.[46] On 30 June 2020, a statement from the International Palaeoentomological Society was published in response to the SVP, criticising the proposal to ban publishing on Burmese amber material.[47] In August 2020, a comment from over 50 authors was published in PalZ responding to the SVP statement. The authors disagreed with the proposal of a moratorium, describing the focus on the Burmese amber as "arbitrary" and that "The SVP’s recommendation for a moratorium on Burmese amber affects fossil non-vertebrate research much more than fossil vertebrate research and clearly does not represent this part of the palaeontological community."[48]

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.[49] A story in Science in 2019 stated: "Two former mine owners, speaking through an interpreter in phone interviews, say taxes have been even steeper since government troops took control of the area. Both shut their mines when they became unprofitable after the government takeover, and almost all deep mines are now out of business, dealers here corroborate. Only shallow mines and perhaps a few secret operations are still running."[7] There were around 200,000 miners working in the Hukawng valley mines prior to the takeover by the Tatmadaw, which shrunk to 20,000 or less after the military operations.[38] Adolf Peretti, a gemologist who owns a museum with Burmese amber specimens, noted that the 2017 cutoff suggested by the SVP does not take into account that the export of Burmese amber prior to 2017 was also funding internal conflict in Myanmar due to the control by the KIA.[38] Much of the amber cutting since 2017 has been done in internally displaced person camps, under humanitarian and non-conflict conditions.[38]

Other Myanmar 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 and Thayet districts of Magway Region and the Bago District of the Bago Region.[50][36]

Tilin amber

A 2018 study on an amber deposit from

bark lice (Lepidopsocidae) as well as extant ant subfamilies Dolichoderinae and tentatively Ponerinae, as well as fragments of moss.[51]

Hkamti amber

The Hkamti site is located ca. 90 km southwest of the Angbamo site and predominantly consists of limestone, interbedded with mudstone and

Thysanoptera.[8] A lizard, Retinosaurus, has also been described from the locality.[52]

See also

References

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External links
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