Description of Units Observed at Lozier Pond, Hyde Park, New York

Unit 1
Coarse Detrital Peat

  • Dark brown, 2.5Y 3/2
  • Macro-organic material ubiquitous, with wood fragments (>10cm length) common.
  • Top of this unit is missing from all stratigraphy in the pond due to several separate excavations of the site.

Unit 2
Humic carbonate-rich silty clay

  • 2.5Y 4/2
  • Transition-zone between peat above and marl below
  • Shelly material (gastropods, bivalves, ostracodes) grade from degraded and fragile at top of section to well preserved and relatively more abundant at base of section.
  • Conversely, plant macrofossils are ubiquitous at top of section, decreasing but still common at base of section.
  • Unit often appears mottled
  • Contact with the unit above tends to be laterally variable, and is identified by a lighter color from that of Unit 1

Unit 3a
Uniform, Humic Silty Marl

  • Generally olive gray 2.5Y 5/2
  • Shells abundant
  • Silt and sand components are significant.
  • Some mottling seen.
  • Faint, visible laminations are rare, but do occur.
  • Contact with the unit above tends to be laterally variable.

Unit 3b
Banded and Laminated Marl

  • Dark gray 5Y 4/1, with lighter gray laminations similar to the olive gray (2.5Y 5/2) of Unit 3a.
  • Width of laminations fluctuates from 0.1 mm to >1 cm.
  • Shell frequency decreases at base of section.
  • Inter-bedded poorly-sorted sands and gravels throughout, often appearing in discontinuous and sub-horizontal lenses. Lamination are generally sub-horizontal and wavy.
  • Cobbles up to 15cm in diameter sometimes present, occasionally appearing to be suspended in matrix, but often contained within poorly-sorted sand and gravel layers.

Unit 4
Massive Clay

  • Bluish-gray 5B 4/1
  • Organic material and shells absent.
  • Clay sediments generally well-sorted, with occasional thin (~1mm) laminations of poorly sorted, angular to subangular silt and sand. Otherwise, clay appears massive.
  • Occasional isolated subrounded cobbles up to 20cm in diameter occur, suspended in matrix.

Basal Gravel

  • Subrounded and subangular, poorly sorted lithic fragments, up to 15cm in diameter.
  • Thickness of unit is at least 30cm, and is interpreted to be glacially derived and present beneath the entire basin.
  • Described in HPM-2 (pit trench).
  • Encountered but not described in core LP2A and LP3A.

PLN 08/26/02